Employee turnover rate: formula and example.

WITH avg_hc AS (
  SELECT AVG(n) AS n
  FROM (
    SELECT m, COUNT(e.employee_id) AS n
    FROM generate_series(DATE '2025-01-01', DATE '2025-12-01', interval '1 month') AS m
    JOIN employees e ON e.hire_date <= m AND (e.termination_date IS NULL OR e.termination_date > m)
    GROUP BY m
  ) s
),
leavers AS (
  SELECT COUNT(*) AS n
  FROM employees
  WHERE termination_date >= DATE '2025-01-01' AND termination_date < DATE '2026-01-01'
)
SELECT l.n AS leavers, ROUND(h.n, 1) AS avg_headcount,
       ROUND(100.0 * l.n / NULLIF(h.n, 0), 1) AS turnover_pct
FROM leavers l CROSS JOIN avg_hc h;

Headcount =
VAR d = MAX ( 'Date'[Date] )
RETURN COUNTROWS ( FILTER ( ALL ( Employees ), Employees[HireDate] <= d && ( ISBLANK ( Employees[TerminationDate] ) || Employees[TerminationDate] > d ) ) )
Turnover % =
DIVIDE (
    CALCULATE ( COUNTROWS ( Employees ), USERELATIONSHIP ( Employees[TerminationDate], 'Date'[Date] ) ),
    AVERAGEX ( VALUES ( 'Date'[YearMonth] ), [Headcount] )
)