How to use the length of service calculator
- Enter the start date, such as a hire date.
- Enter the date to count up to. It starts at today and you can change it to any later date, such as a retirement or review date.
- Under advanced options, enter days that do not count toward service, such as unpaid leave, and the milestone years you want to see.
- Read the length of service in years, months and days, the total days, the years as a decimal and the date each milestone is reached.
Formula
Counted end date = end date - days that do not count
Years, months and days = whole calendar months from the start date, then leftover days
Total days = days from the start date to the end date - days that do not count
Years as a decimal = total days / 365.25
A milestone date is the start date plus whole years, then moved later by the days that do not count. Month ends are handled by keeping the date within the shorter month.
A start date of March 14, 2016
Counting to October 10, 2026, the service is 10 years, 6 months and 26 days. That is 3,862 days, or 10.57 years as a decimal, and 126 full months. The 1, 5 and 10 year milestones are reached. The 15 year milestone falls on March 14, 2031, 1,616 days later.
If 30 days of unpaid leave do not count, the total falls to 3,832 days and the service becomes 10 years, 5 months and 27 days. A start on a leap day, February 29, 2024, counted to February 28, 2025 gives 1 year, because the date is kept inside the shorter month.
Why employers count service
Length of service is often used to set vacation tiers, benefits, service awards and eligibility for retirement plans. Each employer defines what counts: some count from the hire date, some from the start of a benefits plan, and some exclude certain leaves. The tool counts calendar time and the days you remove.
It does not know your employer rules, so enter the start date and excluded days that match your policy.
Related date tools
For any two dates, the days between dates calculator gives the span, and the date calculator adds or subtracts years, months and days. The anniversary calculator counts time between two personal dates, and the PTO accrual calculator shows how leave builds up over time.
Assumptions and limits
- Service is counted in calendar time from the start date, minus the days you enter.
- The end date cannot be before the start date.
- Milestones are whole years from 1 to 80, separated by commas, up to twelve.
- Employer rules for what counts as service vary. This is not legal or payroll advice.
Frequently asked questions
How do I calculate length of service?
Count the whole years and months from the start date to the end date, then the leftover days. From March 14, 2016 to October 10, 2026 that is 10 years, 6 months and 26 days.
How do I exclude unpaid leave?
Enter the days that do not count under advanced options. The tool moves the counted end date back by that many days and recalculates the service and the milestone dates.
How many years of service is 3,862 days?
Divide by 365.25, which gives 10.57 years. The tool shows both the years as a decimal and the years, months and days.
Can I find the date I reach 20 years of service?
Yes. Add 20 to the milestone years in the advanced options and the table shows the date and how many days away it is.