How this calculator works
Tenure can be measured for a group or for one person. Across a team, add up every employee's completed service and divide by the number of employees; the result is the average time a person has stayed. That average is sensitive to a few very long-serving employees and to recent hiring surges, so compare it with the median or with tenure bands when you have them. For one person, enter the starting and ending dates and the calculator counts whole years, then whole months, then the remaining days using calendar months rather than a flat 30-day month. The additional months and days are the remainder after the full years, and the total figures restate the same period in months and days.
Formula
Average tenure = combined service / number of employees. Between two dates, add whole years first, then whole months, then count the remaining days. Total months = full years x 12 + additional months. Total days is the exact calendar difference. Decimal years = total days / 365.25.
Worked example
A team of 50 employees with 325 years of combined service has an average tenure of 6.5 years, or 78 months. From 15 March 2016 to 20 June 2024 is 8 full years, then 3 months to 15 June 2024, then 5 days: 8 years, 3 months and 5 days. That is 99 months and 3,019 days, or about 8.2656 years.
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Frequently asked questions
Should tenure include the current job?
Yes for a snapshot of the workforce. Completed service for former employees and service to the measurement date for current ones. Mixing one definition with another, such as counting only leavers, distorts the average.
Why are the months and days different from a simple division?
Calendar months have different lengths. The calculator advances month by month from the start date, clamping month-end dates so that 31 January plus one month becomes 29 February in a leap year. Dividing total days by 30.44 gives a different, less intuitive answer.
What does a long average tenure tell me?
It suggests stability and experience, but it can also hide low turnover among a group that would benefit from new skills. Pair it with the tenure distribution, promotion rates and the reasons people leave rather than treating one number as good or bad.