How to use this calculator
- Enter or choose current headcount.
- Enter or choose target headcount at end of period.
- Enter or choose expected annual attrition.
- Enter or choose planning period.
- The total hires needed updates as you type. Use Copy result or Share to keep it.
Method
Expected leavers = ⌈(Current + Target) ÷ 2 × Attrition% × Months ÷ 12⌉; Total hires = max(0, Target − Current + Expected leavers)
- ⌈ ⌉
- rounded up to whole people
- Attrition%
- annual rate, scaled to the planning period
Worked example
- Average headcount = (100 + 120) ÷ 2 = 110.
- Expected leavers = 110 × 15% = 16.5, rounded up to 17.
- Total hires = 20 growth + 17 replacements = 37, about 3.08 a month.
Growing from 100 to 120 people with 15% attrition takes about 37 hires over the year.
What the result means
Use the monthly figure to size your recruiting capacity. Hires take time to start, so begin recruiting earlier than the month you need the person.
Assumptions and limits
- Attrition applies to the average headcount over the period and runs at a steady annual rate.
- Every leaver is replaced.
- Notice periods, time to fill and offer declines are not modelled; add a buffer if your pipeline is slow.
Questions
Why use average headcount for leavers?
As the team grows, there are more people who could leave. Averaging start and target reflects that for steady growth.
What if I am reducing headcount?
Enter a lower target. If expected attrition covers the reduction, the hires needed fall to zero.