Use this calculator to find the Incapacitation Score of any handgun cartridge. The Incap Scale is a metric built entirely on the real-world data described on the “Handgun Performance” page. The Stopping Power returned by the calculator is the projected Incapacitation score of the round using the formula that mirrored the empirical data. So far, known values for this measure of stopping power range from 41% for 25 ACP to 96% for 500 S&W. The theoretical maximum score is 100%.
Incapacitation Score Calculator
Bullet Configuration: This result is configuration neutral. That is, it assumes a bullet that is exactly halfway between the worst configuration and the best config for a particular caliber. (This is a minor enhancement, added after the videos on the Handgun Performance page were made.) Here’s how configuration affects the Incap Score, on average:
- All lead/brass hollow point (LHP, BHP): +7
- Other hollow point: +5
- Soft point: -3
- Non-expanding bullet (e.g., full metal jacket, wadcutter): -4
So what’s a “good” Incap Score value? I personally like values in the upper 60s (or higher); they roughly translate to a very solid chance of incapacitating with 2 well-placed shots. See the chart below, which allows us to assess the number of shots needed to reach a 90% probability of incapacitation … given the Incap Score generated by the calculator above. (Use this information with caution; the Incap Scale is solidly backed by real-world data, while the chart below required a higher level of abstraction.) The chart provides a result that is sometimes more intuitively understood. To use the chart, find your Incap Score on the vertical axis, then see where that score intersects the red line. Now find the number of shots on the horizontal axis that also intersects that point on the red line.
Obviously you can’t actually shoot just part of a bullet, but a lower value is always better. For example, the 9mm is far more likely than the 32 to achieve a stop with just 2 critical hits (even though both fall between 2 and 3 shots). Remember also that a well-configured round will increase the Incap Score, pushing the round up and to the left on this chart.
Of course, there are a number of trade-offs in your “best-handgun-for-me” decision: your accuracy with a particular caliber or gun, ease of carry, handling qualities, etc. Incap Score and Critical Hits for 90% are just two data points to help you in that calculus.
