Service Duration Calculator
Calculate your exact length of service from your date of enrolment to any given date.
Last updated 27 July 2026
Calculator
Service Duration Calculator inputs
Enter a date of joining service.
How this works
What it means
Your exact length of service — years, months and days — from your date of joining to any date you choose, plus your next service anniversary.
How it’s calculated
The calculator takes the calendar difference between your date of joining and the date you're calculating until, counting whole years first, then whole months, then remaining days — the same convention used throughout FaujiTips (see the Age Calculator).
Common Defence use cases
Confirming exact colour/reckonable service for annual confidential reports, verifying eligibility windows ahead of a board or review, and cross-checking service records before a posting or discharge.
Formula
years = untilDate.year − joiningDate.year
months = untilDate.month − joiningDate.month
days = untilDate.day − joiningDate.day
if days < 0: months -= 1, days += (days in the month before untilDate)
if months < 0: years -= 1, months += 12Assumptions
- All dates are treated as calendar dates only (no time-of-day or timezone is involved).
- This calculates raw calendar service length only — it does not apply any specific service's rules for broken service, deputation, or leave that may or may not count towards reckonable service.
- A joining date of 29 February is treated as falling on 28 February in non-leap years for anniversary purposes.
Example calculations
Joined 14 July 2010, calculated until 27 July 2026
16 years, 0 months, 13 days — next service anniversary in 352 days
Joined 1 January 2015, calculated until 1 January 2026
11 years, 0 months, 0 days — anniversary is today
Joined 1 March 2020, calculated until 1 March 2025
5 years, 0 months, 0 days — exactly 1,826 days of service