2d Damage
GURPS uses d6 for everything. For purposes of determining damage, GURPS makes use one or several 6-sided dice. 1d6 gives you a flat random distribution. 2d6 gives you linear up --> peak --> linear down. 3d6 (or nd6 where n >= 3) gives you a bell curve. I.e. when you graph these results, 1d6 is flat, 2d6 looks like a pyramid, and 3d6 looks like a bell curve.
I've decide that the 2d6 gives the kind of distribution I want for damage. In general, I think using 2 dice to determine damage should be preferred whenever possible. Furthermore, I want the minimum possible damage to be about 15% of the expected average and the maximum possible damage to be about 185% of the expect average. To that end, the following charts will be used to determine damage:'
Damage Table
| ST | 3d6 thr | 3d6 sw | 2d thr | 2d sw |
|---|---|---|---|---|
| 1 | 1d-6 | 1d-5 | 2d2-4 | 2d2-3 |
| 2 | 1d-6 | 1d-5 | 2d2-4 | 2d2-3 |
| 3 | 1d-5 | 1d-4 | 2d2-3 | 2d3-4 |
| 4 | 1d-5 | 1d-4 | 2d2-3 | 2d3-4 |
| 5 | 1d-4 | 1d-3 | 2d3-4 | 2d2-2 |
| 6 | 1d-4 | 1d-3 | 2d3-4 | 2d2-2 |
| 7 | 1d-3 | 1d-2 | 2d2-2 | 2d3-2 |
| 8 | 1d-3 | 1d-2 | 2d2-2 | 2d3-2 |
| 9 | 1d-2 | 1d-1 | 2d3-2 | 2d4-2 |
| 10 | 1d-2 | 1d | 2d3-2 | 2d4-1 |
| 11 | 1d-1 | 1d+1 | 2d4-2 | d4+d6-1 |
| 12 | 1d-1 | 1d+2 | 2d4-2 | d5+d6-1 |
| 13 | 1d | 2d-1 | 2d4-1 | 2d6-1 |
| 14 | 1d | 2d | 2d4-1 | d6+d8-1 |
| 15 | 1d+1 | 2d+1 | d4+d6-1 | 2d8-1 |
| 16 | 1d+1 | 2d+2 | d4+d6-1 | d8+d10-1 |
| 17 | 1d+2 | 3d-1 | d5+d6-1 | d8+d10-1 |
| 18 | 1d+2 | 3d | d5+d6-1 | d8+d10 |
| 19 | 2d-1 | 3d+1 | 2d6-1 | 2d10 |
| 20 | 2d-1 | 3d+2 | 2d6-1 | d10+d12 |
| 21 | 2d | 4d-1 | d6+d8-1 | 2d12 |
| 22 | 2d | 4d | d6+d8-1 | (d6+d8-1)x2 |
| 23 | 2d+1 | 4d+1 | 2d8-1 | (d5+d10-1)x2 |
| 24 | 2d+1 | 4d+2 | 2d8-1 | (2d8-1)x2 |
| 25 | 2d+2 | 5d-1 | d8+d10-1 | (2d8-1)x2 |
| 26 | 2d+2 | 5d | d8+d10-1 | (2d8-1)x2+1 |
| 27 | 3d-1 | 5d+1 | d8+d10-1 | (2d6-1)x3 |
3d6 to 2d Conversion
| GURPS Avg. | GURPS | 2d | Min | Max | 2d Avg. | Min/Avg. | Max/Avg. |
|---|---|---|---|---|---|---|---|
| 0 | 1d6-6 | 2d2-4 | 0 | 0 | 0 | n/a | n/a |
| 0.2 | 1d6-5 | 2d2-3 | 0 | 1 | 0.25 | 0.00 | 4.00 |
| 0.5 | 1d6-4 | 2d3-4 | 0 | 2 | 0.44 | 0.00 | 4.50 |
| 1 | 1d6-3 | 2d2-2 | 0 | 2 | 1 | 0.00 | 2.00 |
| 1.7 | 1d6-2 | 2d3-2 | 0 | 4 | 2 | 0.00 | 2.00 |
| 2.5 | 1d6-1 | 2d4-2 | 0 | 6 | 3 | 0.00 | 2.00 |
| 3.5 | 1d6 | 2d4-1 | 1 | 7 | 4 | 0.25 | 1.75 |
| 4.5 | 1d6+1 | d4+d6-1 | 1 | 9 | 5 | 0.20 | 1.80 |
| 5.5 | 1d6+2 | d5+d6-1 | 1 | 10 | 5.5 | 0.18 | 1.82 |
| 6 | 2d6-1 | 2d6-1 | 1 | 11 | 6 | 0.17 | 1.83 |
| 7 | 2d6 | d6+d8-1 | 1 | 13 | 7 | 0.14 | 1.86 |
| 8 | 2d6+1 | 2d8-1 | 1 | 15 | 8 | 0.13 | 1.88 |
| 9 | 2d6+2 | d8+d10-1 | 1 | 17 | 9 | 0.11 | 1.89 |
| 9.5 | 3d6-1 | d8+d10-1 | 1 | 17 | 9 | 0.11 | 1.89 |
| 10.5 | 3d6 | d8+d10 | 2 | 18 | 10 | 0.20 | 1.80 |
| 11.5 | 3d6+1 | 2d10 | 2 | 20 | 11 | 0.18 | 1.82 |
| 12.5 | 3d6+2 | d10+d12 | 2 | 22 | 12 | 0.17 | 1.83 |
| 13 | 4d6-1 | 2d12 | 2 | 24 | 13 | 0.15 | 1.85 |
| 14 | 4d6 | (d6+d8-1)x2 | 2 | 26 | 14 | 0.14 | 1.86 |
| 15 | 4d6+1 | (d5+d10-1)x2 | 2 | 28 | 15 | 0.13 | 1.87 |
| 16 | 4d6+2 | (2d8-1)x2 | 2 | 30 | 16 | 0.13 | 1.88 |
| 16.5 | 5d6-1 | (2d8-1)x2 | 2 | 30 | 16 | 0.13 | 1.88 |
| 17.5 | 5d6 | (2d8-1)x2+1 | 3 | 31 | 17 | 0.18 | 1.82 |
| 18.5 | 5d6+1 | (2d6-1)x3 | 3 | 33 | 18 | 0.17 | 1.83 |
Examples
Your character has ST 10, so his basic thrust damage is 2d3-2 and his basic swing damage is 2d4-2.