Call of Cthulhu 7e Skills Guide: Rolls, Difficulty, and the Best Skills

Introduction

Call of Cthulhu 7e skills are percentages, and nearly every uncertain action in the game comes down to rolling under one of them. This guide covers how those rolls work at the table (difficulty, bonus and penalty dice, pushing, criticals, fumbles, and improvement) and then ranks the skills that earn their points in most campaigns.

The rules half is for Keepers and players who want cleaner scenes. The rankings half is for anyone with a blank investigator sheet and a pile of skill points.

Hot Take

The best Call of Cthulhu skill scene starts with a player describing a risky method, not announcing a number on a character sheet. "I compare the shipping manifests to find the missing berth" is a playable plan. "I roll Library Use" is only the mechanical part that follows if the plan creates real uncertainty.

The same goes for character building: the best skill is often the one nobody else at the table has. Library Use, Spot Hidden, and Psychology earn their reputation, but four investigators with the same clue package are still stuck when a car fails on a mountain road or a witness needs medical help. Build a person with a job, then make sure the group can cover the case.

Skills Are Approaches, Not Buttons

Every investigator has skill percentages. Some come from their occupation, some from personal-interest points, and some are base values everyone starts with. The percentage is the investigator's chance when a roll is actually called for, and it also says who that person is in the fiction.

A professor with Library Use, History, and Psychology approaches a mysterious will differently from a dockworker with Mechanical Repair, Listen, and Fighting (Brawl). Neither sheet is a universal solution. Each gives the player plausible ways to contribute.

Think in broad jobs rather than a memorized rules list:

Tell the Keeper what your investigator does, why it might work, and what they want from it. The Keeper then decides which skill or characteristic applies. The Keeper Rulebook gives the Keeper the final say on that choice, because circumstances and opposition matter more than a player shopping for their highest number.

One Clue, Several Approaches

The investigators find a water-stained photograph of a warehouse. A researcher might identify its architecture. A sailor might recognize the mooring layout. A photographer might work out the camera angle and time of day. Someone who talks to the dockmaster may get the answer through a social skill instead. Those are different scenes with different risks, even when they lead to the same next location.

For players, this is permission to use your backstory. For Keepers, it is a reminder to reward a credible approach instead of forcing every group through the same narrow skill gate.

When a Skill Roll Matters

Most of the game should be conversation and description. Investigators do not roll every time they drive across town, read a sign, or ask a reasonable question. The rulebook's own example is Drive Auto: nobody rolls just to drive to the historical society, but a car full of cultists trying to run you off the road is a moment of tension that calls for dice.

Before dice hit the table, establish four things:

1. Goal: What does the investigator want now? "Get through the side door quietly" is clearer than "open the door."
2. Method: What are they doing to get it? A crowbar, a copied key, a lie to the caretaker, and a rooftop route are not the same attempt.
3. Risk: What changes if the attempt fails? Time, attention, evidence, position, trust, or safety should be at stake.
4. Result: What does success buy? A roll should answer a live question, not decorate a conclusion the table already knows.

This keeps failure from feeling arbitrary. It also tells the player enough to decide whether to try another approach, accept the setback, spend Luck if the table uses that optional rule, or push the roll.

Do Not Roll for Routine Competence

The Keeper Rulebook says it plainly: everyday tasks need no dice, and if the Keeper feels a task is easy, no roll is needed. If a clue is essential for the scenario to continue, put it behind several approaches or let an initial failure create a complication rather than erase the clue.

That does not make every clue free. A failed search can cost time, leave traces, alert the wrong person, or produce an incomplete lead. The rules also say an initial failure should not usually cause damage or Sanity loss; the investigator may simply fail to act, like a climber who hesitates at a loose drainpipe instead of falling. The investigation keeps moving, and the cost makes the next decision sharper.

Reading Skill Values

A skill roll is a percentile roll. The Keeper names the relevant skill or characteristic and sets the difficulty. Roll equal to or under the required number to achieve the stated goal.

The investigator sheet records three thresholds for each value: full, half, and one-fifth, rounded down. Fill them in when you record the skill so the table is not doing arithmetic during a chase.

The thresholds do not mean an Extreme result is automatically more impressive than a Regular one. The rulebook is explicit that the fifth, half, and full divisions are not grades of success. Difficulty tells you what result this task needs. The Keeper may narrate an extra benefit, but the player succeeds by meeting the target that was set.

Two results always deserve attention. A roll of 01 is a critical success: something good happens beyond the goal. A fumble is worse than a normal failure. It is a roll of 100 when the required number is 50 or more, or 96 to 100 when the required number is below 50. A fumble takes effect immediately and cannot be pushed away. What it means in the scene is the Keeper's call.

Regular, Hard, and Extreme Difficulty

Regular difficulty is an average challenge for a competent person, and the rules say it should be used in the vast majority of cases. Hard difficulty would challenge a professional and requires half the skill or characteristic; it should appear only occasionally. Extreme difficulty would challenge an expert, sits at the border of what is humanly possible, requires a fifth, and is reserved for extreme situations.

Use difficulty to describe the obstacle, not to punish a player for choosing a strong skill. A thick oak door with an iron lock can make a Strength roll Hard, as in the rulebook's example. Picking a high-security lock with only a piece of wire is one of its Extreme examples. Walking up a familiar staircase needs no roll at all.

When a living opponent resists an action, the Keeper uses the opponent's relevant skill or characteristic to set the difficulty: below 50 is Regular, 50 or more is Hard, and 90 or more is Extreme. The opposing value need not be the same skill. An investigator tailing someone rolls Stealth against a difficulty set by the target's Spot Hidden. This is usually cleaner than an opposed roll, and it keeps the players rolling more often than the Keeper, which the rules recommend.

There is also a hard ceiling. The most an investigator can face with an Extreme success is an opposing value of 100 plus their own skill or characteristic. Beyond that, no roll is allowed unless several investigators combine their physical efforts.

State the Stakes Before the Roll

The same skill changes meaning with the goal. The rulebook contrasts "break the door down" with "lever the door open quietly": the second is a harder goal, and the Keeper sets the difficulty with that in mind. Make the goal concrete before the difficulty is announced, and the result will be easier to narrate honestly.

Bonus and Penalty Dice

Bonus and penalty dice alter the tens digit of a percentile roll. For each bonus die, roll an extra tens die and keep the lower tens result with the same units die. For each penalty die, roll an extra tens die and keep the higher one. One bonus die and one penalty die cancel. Most rolls get a single die at most, but highly favorable or dire conditions can justify a second.

The rules warn that these dice are not small adjustments. Driving in light rain should not earn a penalty die; racing another driver through torrential rain should. A careful setup, excellent tools, or a clear advantage might justify a bonus die. Poor light, a rushed attempt, or a recent serious injury might justify a penalty die.

Do not use a bonus die as vague praise for a clever idea. Let the idea change the fiction first. If it removes the uncertainty, no roll is needed. If it gives a real edge while the risk remains, a bonus die fits. A success rolled with a bonus die also earns no improvement tick, so the advantage has a small cost.

Specializations, Substitutes, and Combined Rolls

Some skills are broad categories split into specializations: Art and Craft, Fighting, Firearms, Language (Other), Pilot, Science, and Survival. You buy the specialization, never the umbrella skill, so a sheet shows Science (Chemistry) or Fighting (Brawl), not "Science" or "Fighting." The specialty should appear in the investigator's occupation, history, or play.

When a player suggests a related but imperfect skill, the Keeper can allow it at a higher difficulty instead of refusing. The rulebook's example is a player cracking a numerical code with Mathematics instead of Cryptography: where Cryptography needed a Regular success, Mathematics needs a Hard one. That acknowledges partial relevance while keeping the difference. The complete skills list covers every specialization and its base value.

Combined Rolls

Some tasks need more than one competence at once. In a combined roll, make one percentile roll and compare it to every named skill. The Keeper says whether both must succeed or whether either is enough. The rulebook's turbine repair needs both Mechanical Repair and Electrical Repair, and a single roll matters: at 10% in each, one roll succeeds 10% of the time, while two separate rolls would both succeed only 1% of the time.

Use a combined roll when both elements happen together. If the group can solve the parts in sequence, run separate scenes so each choice and failure can matter.

Opposed Rolls, Pushed Rolls, and Fumbles

Opposed rolls are for a real contest where both sides have mutually exclusive goals. Each side uses a Keeper-approved skill or characteristic, then compares levels of success: Critical beats Extreme, Extreme beats Hard, Hard beats Regular, and Regular beats a failure or fumble. On a tie, the higher skill or characteristic wins; if that is also tied, the result is an impasse or both sides reroll.

Opposed rolls are the standard for melee combat. Outside combat, the rulebook tells Keepers to avoid them between nonplayer characters and investigators, because an NPC's competence can set the difficulty instead. Opposed rolls cannot be pushed.

Pushing Means Changing the Situation

A pushed roll is a second and final attempt after a failed skill or characteristic roll. It is not a free reroll, and time always passes before it. When a player asks to push, the Keeper should ask what the investigator is doing to push the situation: more effort, more time, more exposure, or more risk. Searching longer might mean being caught in the room. Persuading harder might mean risking arrest.

The Keeper can foreshadow the consequence before the roll, and a failed push gives the Keeper free rein: damage, a Sanity check, lost equipment, isolation, capture, or the goal achieved at a cost. Luck, Sanity, combat, and damage rolls cannot be pushed, and under the optional Luck rule a player chooses between pushing and spending Luck, never both. The full procedure is in the push the roll guide.

Criticals and Fumbles Need Fictional Weight

Do not reduce a critical to "you succeed harder" or a fumble to slapstick. The rulebook's critical example is an appraiser who values a gold crown and also traces it to the South Seas. A critical can add an inference, improve position, save time, or reveal a connection. A fumble should produce an immediate, worse-than-failure result that fits the danger already present.

Improving Skills Between Cases

When an investigator uses a skill successfully in play, tick its box on the sheet. No tick is earned if the roll used a bonus die or if Luck points were spent to change it, and in an opposed roll only the winner ticks. A skill can earn only one tick before the next development phase, however often it succeeded.

The investigator development phase usually comes at the end of a scenario or a campaign chapter. For each ticked skill, roll 1D100. If the result is higher than the current skill, or over 95, add 1D10 to it; otherwise it stays put. Then erase the ticks. Cthulhu Mythos and Credit Rating never receive ticks. When a skill reaches 90% or more during development, the investigator gains 2D6 Sanity.

The system makes low and middling skills easier to improve than expert ones. Keep the tick boxes visible, mark them right after an eligible success, and clear them at the end of development. The skill improvement guide covers the phase in full.

Best Call of Cthulhu Skills by Role

There is no single best Call of Cthulhu investigator. A locked-room mystery, a globe-spanning expedition, a campaign among wealthy socialites, and a desperate rural survival scenario reward different strengths. What carries across most games is a group that can find information, understand people, get into places, and survive being there.

The rankings below measure how often a skill solves problems across campaigns. A skill can rank lower because it is specialized, not because it is weak. Aircraft piloting, Archaeology, Demolitions, Diving, and Natural World can define a campaign when the premise supports them.

How to Use These Rankings

Ask four questions before moving points:

1. What kind of campaign is the Keeper running: city mystery, expedition, historical horror, modern investigation, or something else?
2. What can this investigator credibly do because of their work, history, and connections?
3. Which roles are the other players already covering?
4. What will this investigator do when the investigation turns dangerous?

Occupation points establish professional competence. Personal-interest points make the investigator useful outside their job: a doctor who can spot a tail, an academic who can drive, or a reporter who can handle a revolver. See the occupation skill points guide and the skill points guide before you finalize a sheet.

Tier One: Broad Investigation Skills

These skills are the most likely to create leads, explain clues, or stop the group from missing what is in front of them. The group needs reliable coverage, but that coverage can be spread across players.

Spot Hidden

Physical clues turn up everywhere: a disturbed rug, a hidden compartment, a changed expression across a room. Spot Hidden does not replace player attention. If a player clearly describes searching the desk drawer, the Keeper may simply say what is inside. The skill matters when the clue is concealed, conditions are bad, or the scene is under pressure. The rules also let everyone in position roll Spot Hidden for the same clue, with one success enough, so one strong searcher plus a competent backup usually covers a group.

Library Use

Horror mysteries regularly tie present danger to old records, which makes Library Use a classic campaign skill. It covers archives, newspapers, catalogues, and organized collections, and it works best when the group has a question: who owned the house, which ship brought the artifact, where the name appeared before. In a public library, every investigator can roll and one success is enough. It does little in a street-level emergency, which is why a researcher needs someone who can keep the group alive long enough to use what they find.

Psychology and Listen

People rarely state the truth plainly. Psychology reads demeanor and motive. Listen catches the words, sounds, and changes in the environment the group might miss. Together they make interviews, stakeouts, and tense indoor scenes much sturdier. The Keeper may roll Psychology in secret on the player's behalf, and it should give a read on fear, evasiveness, or divided loyalty, not strip an NPC of mystery.

First Aid

First Aid pays for itself the first time an injured investigator has to keep moving. Damage has consequences, travel is hard, and help may be far away. It is also one of the few skills where two people can work together, with one success enough. Medicine (base 01%) is deeper and suits doctors and forensic or institutional scenes; First Aid is the portable survival purchase for everyone else.

Tier Two: Social Access and Interpretation

Information lives in people as often as in books. A group without social skills can still investigate, but it leaves behind allies, access, and chances to defuse danger before violence starts.

The four interpersonal skills are not interchangeable. Describe what the investigator says and does, and let the Keeper pick the skill. Charm makes someone want to help. Fast Talk creates a quick opening. Persuade gives them a reason. Intimidate makes refusal feel dangerous. A group with two different social approaches is more flexible than one where everyone bullies witnesses.

Credit Rating deserves a note. It can secure rooms, introductions, transport, and a credible place in a social space, and it can stand in for APP when judging first impressions. It never gets improvement ticks, so buy a rating that fits the investigator's life and occupation range rather than expecting it to grow through use. The credit rating guide covers the ranges.

Tier Three: Survival, Access, and Escape

These skills may not find the first clue, but they are often what lets the investigators act on it.

Drive Auto matters more than it looks, because movement is often the investigation. Reaching a remote town, following a suspect, leaving a dangerous place, and moving an injured friend all need a driver. In a group with nobody behind the wheel, every road complication gets worse.

Stealth and Locksmith create options rather than mandatory break-ins. A team that can quietly watch or enter a place chooses when to confront a problem, and in horror the most direct route is often the loudest and worst one. Note that sneaking past a guard is a roll everyone makes, and one failure alerts the guard.

Combat skills sit in this tier because they are insurance, not an answer to the Mythos. Give a combat-capable investigator a credible reason for the skill and a plan for when a weapon is not enough. Combat rolls cannot be pushed, so the plan matters. One person who can cover the retreat is useful; a group built only to fight is poorly prepared to understand what it is fighting.

Setting-Dependent Standouts

The campaign premise can move a skill from niche to essential. Ask the Keeper about the setting before treating any list as universal.

Computer Use and Electronics are Modern-era skills; in a 1920s game, the rulebook points to Physics and Electrical Repair instead. Language skills are both a common trap and a common opportunity. A Language (Other) is excellent when the campaign's places, documents, or communities make it relevant, and a poor generic purchase when nobody can say why the investigator knows it. The same goes for obscure sciences: pick a specialization that gives the Keeper material to put on the table.

Skills That Shine in the Right Concept

Some skills do not rank universally because their value depends on character, setting, and Keeper emphasis. That does not make them bad choices.

Accounting can reveal fraud, hidden ownership, and the money behind a respectable institution. Art and Craft can identify technique, date an object, produce a convincing fake, or support a profession. Disguise can make a social investigator viable where their status is a liability. Photography records a scene and can bring out half-hidden detail the eye missed. Natural World turns landscapes and animal behavior into information. A Science specialization can make a character indispensable when the mystery touches their field.

The test is not "Will this be rolled every session?" Ask instead, "Can I describe a scene where this investigator sees a route nobody else sees?" "My accountant notices the charity's public expenses cannot support its claimed work" is a far better answer than a vague hope that Accounting will matter eventually.

How Much to Invest

There is no universal target number, because difficulty, bonus and penalty dice, table style, and campaign focus all matter. The rulebook's scale helps: 50% to 74% is professional level, enough to earn a living, and 75% to 89% is expert level. A practical shape:

• Put enough points into a defining skill that the investigator can attempt their core job under pressure, ideally 50% or more.
• Give the group's broad skills at least one reliable user instead of leaving every important roll at its base value.
• Keep some personal-interest points for competence outside the occupation.
• Avoid spreading points so thinly that every "trained" skill feels like a gamble.
• Do not chase maximum starting values at the expense of identity and coverage.

High skills stay useful because Hard and Extreme rolls use half and a fifth of the listed value. A 70% skill still gives a 35% Hard target. Even so, an investigator with a few solid capabilities usually contributes more often than a specialist who cannot function outside one controlled setting.

Common Priority Mistakes

Treating combat as the central role. Weapons help you survive a bad round. They do not explain the clue, persuade the witness, or restore anyone's Sanity after learning the truth.

Buying every famous skill. Spot Hidden and Library Use are strong, but the group falls apart as a concept when every investigator is the same amateur detective. Let professional and personal history create differences.

Ignoring movement and recovery. Someone must drive, navigate, repair, climb, swim, or give First Aid when the scenario leaves a comfortable city room.

Assuming the Keeper will cover a missing role. A good scenario offers several paths, but not every path is equally safe or convenient. Group coverage creates choices.

Choosing niche skills with no campaign hook. A niche skill works best when you give the Keeper a reason to feature it. Put its relevance in the investigator's background or raise it before play.

Build a Useful Investigator

Start with the investigator's practical identity. An occupation gives a professional profile. Personal-interest points should make that person interesting when the case leaves the office, lecture hall, ship, or precinct.

Do not try to cover the whole game alone. A strong investigator normally has:

• one or two skills that explain their work;
• one way to notice, research, or interpret evidence;
• one way to handle people, even if it is blunt or awkward;
• one survival, movement, or practical skill that matters in action scenes;
• a reason for their personal-interest choices in the backstory.

At character creation, compare concepts before everyone spends their last points. You do not need a rigid party, but you need answers to recurring questions:

• Who can reliably search a place and research a lead?
• Who can get useful information from an unwilling person?
• Who can treat an injury or keep the group moving?
• Who can operate transport, navigate, or repair equipment?
• Who can get into or out of a controlled location?
• Who has setting knowledge the others lack?

Overlap is fine when it adds redundancy without sameness. Two people with modest Spot Hidden is sensible. Four people who all rely on Fast Talk and nobody with First Aid is brittle. Let occupations set distinct professional identities, then use personal interests to tie them to the campaign's actual demands.

Record the final values, with their half and fifth, on the character sheet. Credit Rating and Luck also shape what problems the character can absorb, even though neither replaces a well-chosen skill.

Running Skills at the Table

Player Guidance

Lead with intent. Name the person you approach, the evidence you examine, the route you take, or the tool you use. Ask what failure looks like when it is not obvious, so you can choose a different approach before committing to the roll.

When you fail, keep playing the scene. A failure tells you the current method did not work; it is not a signal to repeat the roll until the dice cooperate. Change the plan, bring in another investigator, find a pressure point, accept a cost, or make a properly justified push. The rules treat a second attempt at the same goal as a push in most cases.

Keeper Guidance

Call for dice at moments of tension, not as a toll every time someone names a skill. Ask for a stated goal, share the difficulty when that helps, and decide what an ordinary failure changes before the dice roll. Save the sharpest consequences for a failed push or a fumble the fiction has earned.

Give important information more than one route. A skilled investigator should feel capable, but capability is not control. Let success buy speed, privacy, a bargaining chip, a better position, or richer context. Let failure keep the case alive while closing the easy route. When the whole group can reasonably help, as with a library search or a room full of possible clues, let everyone roll and take the best result.

Skills Checklist

Before the next skill roll, ask:

1. What exactly is my investigator trying to accomplish?
2. What method are they using, and why does this skill fit?
3. Is this a moment of real tension, or should it just happen?
4. What difficulty reflects the obstacle?
5. What changes on success and on an ordinary failure?
6. Does the current fiction justify a bonus or penalty die?
7. If the roll fails, can the investigator change the situation enough to justify a push?

Before finalizing an investigator, confirm:

• The investigator has a credible professional core.
• The group covers physical clues, research, people, and basic survival.
• Someone can move, escape, or repair the group's equipment.
• Setting-dependent skills were chosen because the campaign supports them.
• This character brings a distinct approach instead of copying the group.
• Combat skills are a fallback, not the only plan.
• You can name a scene where each unusual skill makes this investigator valuable.

Skills work best when every answer keeps the investigation moving and makes each investigator a distinct, fallible person facing problems nobody should have to solve.

Related Guides

The Call of Cthulhu 7e Guide Hub links out to every topic guide in this collection, from character creation through combat, magic, sanity, and Keeper resources. The skills-specific library and cross-system links below go deeper on rolls, difficulty, and character building.

Skills Guide Library

Cross-System Guides

• Call of Cthulhu 7e Character Creation
• Call of Cthulhu 7e Occupations
• Call of Cthulhu 7e Character Sheet Guide
• How to Play Call of Cthulhu 7e