D&D 5e CR Calculator

Enter what your monster does and this works out its challenge rating the way the Dungeon Master's Guide does — a defensive rating from hit points and armour class, an offensive rating from damage and accuracy, then the average of the two. It shows both halves and the comparisons it made, so when you disagree with the answer you can see exactly where it came from.

The average on the stat block. Resistances are counted from the next field.
Or to nonmagical weapon damage. Counted as extra hit points, as the DMG does.
The number on the stat block.
Average over three rounds, multiattack included.
Best to-hit bonus. Leave blank for a pure caster.
Used only when there is no attack bonus.

Enter hit points to begin.

How challenge rating actually works

Challenge rating is meant to answer one question: how hard is this creature for four characters of that level? The Dungeon Master's Guide answers it by measuring two things separately and then splitting the difference.

The defensive half

Start with effective hit points and read off the rating whose band it falls in. Then compare armour class against what the guide expects at that rating: for every 2 points of difference, move one step up or down the ladder. A creature with a lot of hit points and no armour is not as tough as its hit points suggest, and the adjustment says so.

"Effective" is doing work in that sentence. Resistance to common damage types is worth counting as extra hit points; so is a large pool of temporary hit points, or regeneration the party has no obvious way to stop. The guide suggests treating resistance to most damage as roughly double the hit points at low rating, less at high rating, on the grounds that high-level parties carry answers.

The offensive half

Take average damage over the first three rounds — the creature doing the most damaging thing it can, every attack landing — and read off the rating. Then compare attack bonus against the expected value the same way: 2 points to a step. A creature that hits like a truck and never connects is not as dangerous as its damage suggests.

For a creature that mostly casts, use the save DC of its best spell instead of an attack bonus. The calculator above does this automatically when you leave the attack bonus blank.

The average, and why it lies

Average the two ratings and round. That is the method, in full — and it is worth knowing how loosely it holds. Run the SRD Ogre through the book's own tables: 59 hit points and AC 11 give a defensive rating of 1/4, 13 damage a round at +6 to hit gives an offensive rating of 2, and the average is 1. The printed stat block says CR 2.

That is not a bug in this calculator, and it is not a bug in the Ogre. The method cannot see action economy, legendary actions, pack tactics, a breath weapon that ends an encounter on round one, or the difference between a monster fought in a corridor and the same monster fought in an open field. It measures a stat block. Encounters are not stat blocks.

What to do with the number

  • Treat it as a sanity check, not a verdict. If you wrote a CR 5 monster and the method says 9, something is out of proportion and it is worth looking at which half moved.
  • Look at the two halves separately. A big gap between them usually means the creature is a glass cannon or a damage sponge, which is a design decision — just make it on purpose.
  • Round toward your table. A party with a paladin and a moon druid handles a bruiser differently from a party of four casters. No table knows that.
  • Playtest the ones that matter. For a boss, run the first three rounds on paper against your actual party's armour class and hit points before the session.

Frequently asked questions

How is challenge rating calculated in D&D 5e?

Two ratings, averaged. Defensive from hit points, adjusted by armour class; offensive from damage per round, adjusted by attack bonus or save DC. Every adjustment is one step per 2 points of difference from the expected value at that rating.

Why does this disagree with a monster's official CR?

Because the method and Wizards of the Coast's own assignments often disagree — the Ogre above is one of many. Use the method to find things that are wildly out of place, not to settle arguments about whether a creature is CR 6 or CR 7.

What counts as damage per round?

Average damage across the first three rounds, assuming everything hits and the creature uses its best option. Include multiattack. If a limited-use ability such as a breath weapon fires once, spread it over the three rounds rather than counting it every round.

Is it free?

Yes, with no account. It runs in your browser, so nothing you type is sent anywhere. If you want the whole stat block rather than the number, the Monster Creator does this calculation continuously as you build.

Monster statistics by challenge rating

This is the table the calculator above works from — the Dungeon Master's Guide's expected values at every challenge rating from 0 to 30. It is worth reading on its own: most of the time you do not need a calculator, you need to know whether the number you already picked is roughly in the right place.

CR XP Prof. AC Hit points Attack Damage / round Save DC
0 10 +2 13 1–6 +3 0–1 13
1/8 25 +2 13 7–35 +3 2–3 13
1/4 50 +2 13 36–49 +3 4–5 13
1/2 100 +2 13 50–70 +3 6–8 13
1 200 +2 13 71–85 +3 9–14 13
2 450 +2 13 86–100 +3 15–20 13
3 700 +2 13 101–115 +4 21–26 13
4 1,100 +2 14 116–130 +5 27–32 14
5 1,800 +3 15 131–145 +6 33–38 15
6 2,300 +3 15 146–160 +6 39–44 15
7 2,900 +3 15 161–175 +6 45–50 15
8 3,900 +3 16 176–190 +7 51–56 16
9 5,000 +4 16 191–205 +7 57–62 16
10 5,900 +4 17 206–220 +7 63–68 16
11 7,200 +4 17 221–235 +8 69–74 17
12 8,400 +4 17 236–250 +8 75–80 17
13 10,000 +5 18 251–265 +8 81–86 18
14 11,500 +5 18 266–280 +8 87–92 18
15 13,000 +5 18 281–295 +8 93–98 18
16 15,000 +5 18 296–310 +9 99–104 18
17 18,000 +6 19 311–325 +10 105–110 19
18 20,000 +6 19 326–340 +10 111–116 19
19 22,000 +6 19 341–355 +10 117–122 19
20 25,000 +6 19 356–400 +10 123–140 19
21 33,000 +7 19 401–445 +11 141–158 20
22 41,000 +7 19 446–490 +11 159–176 20
23 50,000 +7 19 491–535 +11 177–194 20
24 62,000 +7 19 536–580 +12 195–212 21
25 75,000 +8 19 581–625 +12 213–230 21
26 90,000 +8 19 626–670 +12 231–248 21
27 105,000 +8 19 671–715 +13 249–266 22
28 120,000 +8 19 716–760 +13 267–284 22
29 135,000 +9 19 761–805 +13 285–302 22
30 155,000 +9 19 806–850 +14 303–320 23