The DMG has a table for calculating encounters (replicated below), but I find this presentation to be less confusing. You pick a CR (rows) and a number of creatures (columns) and the number in the cell indicates the EL.
Number of creatures | ||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | |||
Challenge Rating | ||||||||||||||||||||||
1 | 1 | 2 | 3 | 4 | 5 | 5 | 6 | 6 | 6 | 7 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 8 | 8 | 9 | ||
2 | 2 | 4 | 5 | 6 | 7 | 7 | 8 | 8 | 8 | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 10 | 10 | 10 | 11 | ||
3 | 2 | 4 | 5 | 6 | 7 | 7 | 8 | 8 | 8 | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 10 | 10 | 10 | 11 | ||
4 | 4 | 6 | 7 | 8 | 9 | 9 | 10 | 10 | 10 | 11 | 11 | 11 | 11 | 12 | 12 | 12 | 12 | 12 | 12 | 13 | ||
5 | 5 | 7 | 8 | 9 | 9 | 10 | 10 | 11 | 11 | 11 | 12 | 12 | 12 | 12 | 12 | 13 | 13 | 13 | 13 | 13 | ||
6 | 6 | 8 | 9 | 10 | 11 | 11 | 12 | 12 | 12 | 13 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 14 | 14 | 15 | ||
7 | 7 | 9 | 10 | 11 | 12 | 12 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 15 | 15 | 15 | 15 | 15 | 15 | 16 | ||
8 | 8 | 10 | 11 | 12 | 13 | 13 | 14 | 14 | 14 | 15 | 15 | 15 | 15 | 16 | 16 | 16 | 16 | 16 | 16 | 17 | ||
9 | 9 | 11 | 12 | 13 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 17 | 17 | 18 | ||
10 | 10 | 12 | 13 | 14 | 15 | 15 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 18 | 18 | 18 | 18 | 18 | 18 | 19 | ||
11 | 11 | 13 | 14 | 15 | 16 | 16 | 17 | 17 | 17 | 18 | 18 | 18 | 18 | 19 | 19 | 19 | 19 | 19 | 19 | 20 | ||
12 | 12 | 14 | 15 | 16 | 17 | 17 | 18 | 18 | 18 | 19 | 19 | 19 | 19 | 20 | 20 | 20 | 20 | 20 | 20 | 21 | ||
13 | 13 | 15 | 16 | 17 | 18 | 18 | 19 | 19 | 19 | 20 | 20 | 20 | 20 | 21 | 21 | 21 | 21 | 21 | 21 | 22 | ||
14 | 14 | 16 | 17 | 18 | 19 | 19 | 20 | 20 | 20 | 21 | 21 | 21 | 21 | 22 | 22 | 22 | 22 | 22 | 22 | 23 | ||
15 | 15 | 17 | 18 | 19 | 20 | 20 | 21 | 21 | 21 | 22 | 22 | 22 | 22 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | ||
16 | 16 | 18 | 19 | 20 | 21 | 21 | 22 | 22 | 22 | 23 | 23 | 23 | 23 | 24 | 24 | 24 | 24 | 24 | 24 | 25 | ||
17 | 17 | 19 | 20 | 21 | 22 | 22 | 23 | 23 | 23 | 24 | 24 | 24 | 24 | 25 | 25 | 25 | 25 | 25 | 25 | 26 | ||
18 | 18 | 20 | 21 | 22 | 23 | 23 | 24 | 24 | 24 | 25 | 25 | 25 | 25 | 26 | 26 | 26 | 26 | 26 | 26 | 27 | ||
19 | 19 | 21 | 22 | 23 | 24 | 24 | 25 | 25 | 25 | 26 | 26 | 26 | 26 | 27 | 27 | 27 | 27 | 27 | 27 | 28 | ||
20 | 20 | 22 | 23 | 24 | 25 | 25 | 26 | 26 | 26 | 27 | 27 | 27 | 27 | 28 | 28 | 28 | 28 | 28 | 28 | 29 |
This is similar to the same table listed in the DMG. You pick a desired EL (rows) and the number of creatures (columns), and the number in the cell indicates the CR of those creatures.
Number of creatures | ||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | |||
Encounter Level | ||||||||||||||||||||||
1 | 1 | 0.5 | 0.33 | 0.25 | 0.2 | 0.17 | 0.14 | 0.13 | 0.11 | 0.1 | 0.09 | 0.08 | 0.08 | 0.07 | 0.07 | 0.06 | 0.06 | 0.06 | 0.05 | 0.05 | ||
2 | 2 | 1 | 0.67 | 0.5 | 0.4 | 0.33 | 0.29 | 0.25 | 0.22 | 0.2 | 0.18 | 0.17 | 0.15 | 0.14 | 0.13 | 0.13 | 0.12 | 0.11 | 0.11 | 0.1 | ||
3 | 2 | 1 | 0.67 | 0.5 | 0.4 | 0.33 | 0.29 | 0.25 | 0.22 | 0.2 | 0.18 | 0.17 | 0.15 | 0.14 | 0.13 | 0.13 | 0.12 | 0.11 | 0.11 | 0.1 | ||
4 | 4 | 2 | 1 | 1 | 0.8 | 0.67 | 0.57 | 0.5 | 0.44 | 0.4 | 0.36 | 0.33 | 0.31 | 0.29 | 0.27 | 0.25 | 0.24 | 0.22 | 0.21 | 0.2 | ||
5 | 5 | 3 | 2 | 1 | 1 | 0.83 | 0.71 | 0.63 | 0.56 | 0.5 | 0.45 | 0.42 | 0.38 | 0.36 | 0.33 | 0.31 | 0.29 | 0.28 | 0.26 | 0.25 | ||
6 | 6 | 4 | 3 | 2 | 2 | 1 | 1 | 1 | 0.89 | 0.8 | 0.73 | 0.67 | 0.62 | 0.57 | 0.53 | 0.5 | 0.47 | 0.44 | 0.42 | 0.4 | ||
7 | 7 | 5 | 4 | 3 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 0.92 | 0.85 | 0.79 | 0.73 | 0.69 | 0.65 | 0.61 | 0.58 | 0.55 | ||
8 | 8 | 6 | 5 | 4 | 3 | 3 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 0.94 | 0.89 | 0.84 | 0.8 | ||
9 | 9 | 7 | 6 | 5 | 4 | 4 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | ||
10 | 10 | 8 | 7 | 6 | 5 | 5 | 4 | 4 | 4 | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | ||
11 | 11 | 9 | 8 | 7 | 6 | 6 | 5 | 5 | 5 | 4 | 4 | 4 | 4 | 3 | 3 | 3 | 3 | 3 | 2 | 2 | ||
12 | 12 | 10 | 9 | 8 | 7 | 7 | 6 | 6 | 6 | 5 | 5 | 5 | 5 | 4 | 4 | 4 | 4 | 4 | 4 | 3 | ||
13 | 13 | 11 | 10 | 9 | 8 | 8 | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 5 | 5 | 5 | 5 | 5 | 4 | 4 | ||
14 | 14 | 12 | 11 | 10 | 9 | 9 | 8 | 8 | 8 | 7 | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 5 | ||
15 | 15 | 13 | 12 | 11 | 10 | 10 | 9 | 9 | 9 | 8 | 8 | 8 | 8 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | ||
16 | 16 | 14 | 13 | 12 | 11 | 11 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 8 | 8 | 8 | 7 | ||
17 | 17 | 15 | 14 | 13 | 12 | 12 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 9 | 9 | 8 | ||
18 | 18 | 16 | 15 | 14 | 13 | 13 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | ||
19 | 19 | 17 | 16 | 15 | 14 | 14 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 11 | 10 | ||
20 | 20 | 18 | 17 | 16 | 15 | 15 | 14 | 14 | 14 | 13 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 12 | 11 |