Work out severity rate instantly with clear inputs, formula shown and shareable results.
Severity rate normalises days lost rather than injury count, so it captures how serious the injuries were rather than how many occurred. Read alongside frequency rate it distinguishes a site with many minor injuries from one with few but disabling ones, and average days per injury is the ratio between the two.
Severity rate
Rate = days lost x base hours / hours worked
Average severity
Days per injury = days lost / lost time injuries
Rate = days lost x base hours / hours worked. Severity rate normalises days lost rather than injury count, so it captures how serious the injuries were rather than how many occurred.
Conventionally a fatality or permanent total disability is charged at 6000 days so that severe outcomes dominate the statistic as they should. Practice varies, so the basis must be stated.
This calculator takes 4 inputs: Days lost, Lost time injuries, Hours worked, Base hours for the rate. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.