How to calculate Employee Retention Rate

Formula

Retention rate = employees at start who are still employed at end ÷ employees at start × 100

SQL query

This example assumes: employees(id, department, start_date, end_date). It is written in PostgreSQL syntax; date functions differ slightly in MySQL, BigQuery and SQLite, and your column names will differ from these.

SELECT department,
       COUNT(*) FILTER (WHERE end_date IS NULL OR end_date > DATE '2026-12-31') * 100.0
         / NULLIF(COUNT(*), 0) AS retention_pct
FROM employees
WHERE start_date <= DATE '2026-01-01'
  AND (end_date IS NULL OR end_date > DATE '2026-01-01')
GROUP BY department
ORDER BY retention_pct;

Common mistakes that make Employee Retention Rate wrong

• Hires made during the period must not be in the numerator.
• Internal transfers are retained employees, not leavers.
• Retention is not 100 minus turnover when hiring happened during the period.

Ask for Employee Retention Rate in plain English

Instead of writing the query yourself, you can type the question. SchemaChat turns it into SQL against your connected database or uploaded file, runs it, and shows the SQL and the figures it used so you can check the answer before you share it. It does not replace your judgement about the definition: check that the query matches the formula your business uses.

• What was retention of the January headcount by department?
• How does retention differ by tenure band?