Quick answer
Calculate the anniversary from the recognised start date, then check whether the milestone programme counts anniversaries or credited service.
The anniversary is simple
Add whole years to the recognised start date. Someone starting 12 September 2019 has anniversaries on 12 September each year, and the fifth one falls in 2024. Nothing complicated happens unless the start date is 29 February.
That case needs the usual convention — 28 February or 1 March in non-leap years — and for an internal recognition programme it is entirely a matter of choosing one and being consistent.
Use this guide with the right tool: Open the Work Anniversary Calculator for the next employment anniversary and completed service years. If the question shifts, compare it with the Service Milestone Calculator or the Years of Service Calculator.
Where milestones diverge
A recognition programme based on anniversaries and one based on credited service give the same answer for anyone with unbroken service. They diverge for anyone with an excluded period: an employee with a six-month unpaid break reaches their tenth anniversary six months before their tenth year of credited service.
That is not a rounding difference; it is a real question about who gets the award and when. Decide which basis the programme uses, write it down, and expect people to notice if it changes.
Rehires and bridged service
An employee who leaves and returns has two start dates. Some policies bridge short gaps and restore the original service date; others restart the clock. Both are common and the difference can be years of recognised service.
Where bridging applies, record both the original and the current start date along with the policy that connects them. A single date in the file loses the reasoning and will be queried eventually.
Making the reminder useful
A useful anniversary record includes the recognised start date, the next anniversary date, its weekday, and the number of completed years it represents. Weekday matters more than it sounds: an anniversary falling on a Sunday needs marking on a different day.
Derive the anniversary from the start date rather than storing a list of dates. A stored list needs annual maintenance and drifts the first time someone forgets.
Worked example
Try it with the dates in front of you. Where the answer sits close to a threshold, treat that as a prompt to check the rule rather than to conclude.
Common mistakes to avoid
- Counting calendar years as service years. A year of service completes on the anniversary, not at the year end.
- Assuming anniversary and credited service match. They diverge for anyone with an excluded period. State which the programme uses.
- Using payroll start instead of the recognised service date. They can differ, and after a transfer or rehire the difference can be years.
Use the right calculator
Three tools cover most of what this guide describes. Each shows its working, so a result can be checked rather than trusted.
Frequently asked questions
What about a 29 February start date?
Use the usual convention for non-leap years — 28 February or 1 March — and apply it consistently.
Does a rehire restore previous service?
It depends on the policy. Some bridge short gaps; some restart. Record both dates and the rule.
Which basis should a recognition programme use?
Either works. What matters is that it is documented, because employees compare notes.