The formula
How to calculate employee turnover rate
Employee turnover is the share of the workforce that leaves in a year. Attaching a cost to it is what moves the conversation from an HR statistic to a budget line.
Replacement cost estimates vary from 20% of salary for routine roles to well over 100% for senior or specialist ones. It covers advertising, agency fees, interview time, onboarding and the months before a new hire is fully productive.
The inputs, one by one:
- Employees who left
- Average headcount — opening plus closing headcount, divided by two
- Average salary
- Replacement cost (% of salary) — recruitment, onboarding and lost productivity
Everything recalculates as you type, and the numbers in the address bar update with it, so a link to this page carries your figures with it.
The order the fields are filled in makes no difference to the result — the calculator recomputes the whole formula from whatever is currently in every field, not step by step. That means it is safe to adjust one number, watch the result change, and adjust it back, without worrying about resetting anything first.
Why employee turnover rate matters
Most people who look up a employee turnover rate calculation already have a specific number in mind — a quote, an offer, a target — and want to check it rather than learn the theory behind it. This page is built for that: enter your own figures, see the result immediately, and change any field to see how the answer moves without redoing the arithmetic from scratch each time.
It is also useful as a sense check before signing anything. A quote, an offer letter or a spreadsheet from someone else can contain an error, an optimistic assumption, or simply a different convention for rounding — running the same inputs through an independent calculator is a quick way to confirm a number before relying on it.
This kind of calculation rarely stands entirely alone. A employee turnover rate figure usually feeds into a wider decision — how it compares with a competing offer, whether it fits inside a monthly budget, what it does to a longer-term plan — and the value of having it as an exact number rather than a rough guess is that those follow-on comparisons stop being guesswork too. Once one figure in a decision is precise, it is worth making the effort to get the others precise as well, rather than mixing an exact calculation with several estimates and treating the result as equally reliable.
A calculator like this one is often bookmarked and returned to repeatedly over months rather than used once, particularly for anything tied to an ongoing plan such as a mortgage, a savings goal or an investment being tracked. Because the figures live in the web address rather than only in memory, coming back to the same page with updated numbers is quicker than starting from a blank spreadsheet each time.
Worked example
Work through the defaults on this page:
- Employees who left: 18
- Average headcount: 120
- Average salary: 38,000
- Replacement cost: 35 % of salary
That gives:
- Turnover rate: 15 %
- Estimated annual cost: 239,400
- Cost per leaver: 13,300
These figures are only the calculator's own starting values, included so the working is visible rather than hidden inside the tool above. Replace them with your own numbers and the same arithmetic applies — nothing about the method changes, only the inputs feeding it.
Reading the result
UK averages sit around 15%, with hospitality and retail far higher and professional services lower. What matters more than the rate is who is leaving: 10% turnover concentrated in your best performers is worse than 20% spread evenly.
Where this goes wrong. Not separating voluntary from involuntary departures. Redundancies, dismissals and retirements tell you something different from resignations, and lumping them together hides the signal.
A useful check on any unfamiliar result is to compare it against a rough mental estimate first — round the inputs to convenient numbers and see whether the calculator's answer lands in roughly the same territory. A wildly different figure usually means one of the fields was entered in the wrong unit, most often a percentage typed as a whole number where a decimal was expected, or the reverse.
Roughly 10–15% for most sectors. Very low turnover is not automatically good — some renewal brings new skills, and near-zero can indicate stagnation.
They are usually used interchangeably. Where a distinction is drawn, attrition means roles left unfilled after someone leaves, while turnover means departures that are replaced.
The headline figure is turnover rate. With 18 employees who left, 120 average headcount and 38,000 average salary, that comes to 15 %. Change any field and the figure moves with it.
Whenever one of the underlying figures changes — a new interest rate, a different balance, an updated term — since the result only reflects what is currently in the fields. There is no need to keep a separate record of past results; the web address for a filled-in version already carries the figures used to produce it.
Not unless a tax rate or a fee is explicitly one of the inputs above. Where it is not, the figure shown is a gross calculation, and any tax due depends on your personal circumstances and current tax rules, which are worth checking separately.
The arithmetic itself is exact — the calculator applies the formula shown above precisely, with no rounding until the final figure is displayed. The uncertainty, where it exists, is entirely in the inputs: an estimated rate or an approximate balance carries that same approximation through to the result.