Employee Retention Rate vs. Turnover Rate: What's the Difference?

Retention rate and turnover rate are two of the most quoted numbers in HR, and they are often treated as if they are simply opposites — if turnover is 15%, retention must be 85%, right? Not quite. The two metrics measure related but distinct things, and using them interchangeably can lead to the wrong conclusions.

What each metric measures

Turnover rate captures how many people left over a period, relative to the typical size of your team. Retention rate captures how many people stayed, relative to who you started with. They look at the same workforce from opposite ends — departures versus survivors — but they are usually calculated with different denominators, which is why they do not always add up to a tidy 100%.

The formulas side by side

• Turnover rate = (employees who left ÷ average headcount) × 100
• Retention rate = ((employees at start − employees who left) ÷ employees at start) × 100

Notice the denominators. Turnover typically divides by the average headcount over the period, while retention divides by the starting headcount. That difference is exactly why the two figures rarely sum to 100.

A worked example

Suppose a team starts the year with 100 people, ends with 120, and 12 people leave along the way.

1. Average headcount: (100 + 120) ÷ 2 = 110.
2. Turnover rate: 12 ÷ 110 = 10.9%.
3. Retention rate: (100 − 12) ÷ 100 = 88%.

Turnover is 10.9% and retention is 88% — and 10.9 + 88 does not equal 100, because the two ratios are built on different bases. Both are correct; they just answer slightly different questions.

A key difference: new hires

Retention rate, measured against the starting headcount, deliberately ignores people you hired during the period — it asks how well you kept the team you began with. Turnover, using average headcount, folds growth into the denominator. That makes retention a cleaner measure of whether your existing people are staying, and turnover a better measure of overall churn in a changing organization.

When to use which

• Use retention rate when you want to know how well you are holding on to existing employees, especially a specific cohort or your top performers.
• Use turnover rate when you want an overall measure of churn that accounts for a team that is growing or shrinking, and to compare against industry benchmarks.

Track both together

The two metrics are most powerful side by side: retention shows loyalty, turnover shows movement. The employee turnover calculator reports both at once — turnover rate, retention rate, and an annualized figure — so you can watch them together instead of guessing how one implies the other.