How to Calculate an Arcana Check (D&D 5e)
calendar_monthPublished 2026-08-16verified_userReviewed by Calculopedia editorial
Arcana is the D&D 5e Intelligence skill that covers remembering and identifying things arcane: spells, magic items, arcane symbols, ley lines and the secret histories of magical traditions. When your character squints at a glowing rune and tries to recall what it does, the Dungeon Master calls for an Arcana check. Unlike the "appraisal" skills, Arcana is about knowledge — what you can recall, recognise and reason through about the magical world.
Every check in D&D follows the same elegant shape: roll a d20, add a relevant modifier, and compare the total to a Difficulty Class (DC) the DM sets. Arcana just tells you which modifier to reach for. Once you know the pattern, Arcana is one of the easiest skills to calculate on the fly — it's the same arithmetic as any other ability check.
The formula
Arcana check = d20 roll + Intelligence modifier + proficiency bonus
- d20 roll — the twenty-sided die, producing a random value from 1 to 20.
- Intelligence modifier — Arcana is keyed to Intelligence (which runs roughly from −1 to +5 for most adventurers).
- Proficiency bonus — added only if your character is proficient in Arcana. It starts at +2 at level 1 and climbs to +6 at high levels. Expertise doubles it.
The trick is remembering the two conditional terms. Everyone adds their Intelligence modifier; only those trained in Arcana add proficiency, and only specialists with Expertise double it.
Proficiency bonus by level
| Character level | Proficiency bonus |
|---|---|
| 1–4 | +2 |
| 5–8 | +3 |
| 9–12 | +4 |
| 13–16 | +5 |
| 17–20 | +6 |
This progression is identical across all skills — it's baked into the game's math and grows across a campaign. A level 17 wizard, for instance, carries a +6 proficiency before any class features or ability bonuses kick in.
Worked example
Consider a level 9 wizard. At level 9 the proficiency bonus is +4. With an Intelligence of 18 (modifier +4) and proficiency in Arcana, the character rolls a 12:
Arcana = 12 + 4 + 4 = 20
A total of 20 on an Arcana check is a solid success against most DCs. The DM might reveal the school of magic at work, the function of the item, or a hidden vulnerability — the higher the roll, the richer the detail.
Reading the total
The DM sets the DC based on how obscure the knowledge is. As a rough mental model, most DMs use something like this:
| Total | What the DM might reveal |
|---|---|
| 30+ | Obscure arcane secrets, hidden history |
| 20+ | Deep understanding of the effect and its source |
| 15+ | Useful insight into the magic at work |
| 10+ | Basic facts about the spell or item |
| <10 | Little or nothing recalled |
These bands are guidelines, not rules — a DM might set a DC of 12 for identifying a common magic item and DC 25 for a lost ritual. The higher your check, the more of that knowledge the DM doles out.
With Expertise
Some wizards, bards and certain other builds can take Expertise, which doubles the proficiency bonus. For our level 9 wizard:
Arcana = 12 + 4 + (4 × 2) = 24
That +8 bump turns a solid check into a near-encyclopaedic one. Expertise is where Arcana really shines — it makes a specialist genuinely exceptional at recalling arcane lore.
The role of the DC
The DC is the number you must meet or beat. A check of exactly the DC succeeds; anything below fails. The DM decides the DC on the spot or from an adventure's stat block, so knowing your modifiers lets you compute your roll instantly and celebrate (or dread) the result.
Two practical notes:
- Passive vs active. If a player isn't actively searching for it, some DMs avoid asking for checks and rely on passive scores instead — but Arcana is almost always an active, intentional attempt to recall something, so you'll typically be rolling.
- Advantage and disadvantage. Circumstances can grant advantage (roll twice, take the higher) or impose disadvantage (roll twice, take the lower). These change the effective odds without changing the formula above.
Key takeaways
- Arcana = d20 + Intelligence modifier + (proficiency bonus, if proficient).
- Proficiency grows from +2 to +6 by level; Expertise doubles it.
- Compare the total to the DM's DC to see how much arcane knowledge you recover.
- Keep your modifier sheet handy so you can total a check in seconds during play.
FAQ
Is Arcana the same as identifying every magic item? No. Arcana covers knowledge about magic generally, but DMs often require rules like identifying a magic item (which may need a short rest or a dedicated action) or use other skills for creatures. Check with your DM how they handle item identification at their table.
Do I add proficiency if I'm not proficient in Arcana? Only if you have another feature that grants it. Without proficiency, the check is just d20 + Intelligence modifier.
Can I use Arcana passively? Not typically. It's an active recall skill, so you'll almost always roll rather than use a passive score. The DM might, however, let passive Arcana reveal whether something seems familiar without an explicit attempt.
What's a good Arcana score? An Intelligence-focused, proficient caster can easily reach 20+ on a strong roll. That's enough to recall most arcane lore the DM throws at you.
Total up your check with the Arcana Calculator, and keep an eye on hidden threats with the Passive Perception Calculator so your wizard isn't caught reading the wrong scroll at the wrong moment.