Years Between Two Dates
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About this calculator
Calculate how many years are between two dates. The result includes decimal fractions — for example, 2.5 years means two years and six months. Useful for age calculations, anniversary tracking, and understanding long-term time spans.
How it works
The calculator computes the total difference in seconds and divides by 31,557,600 — the number of seconds in one average year (365.25 days × 24 hours × 60 minutes × 60 seconds). The 365.25-day year accounts for leap years by averaging over the four-year leap cycle. Decimal results show partial years: 0.25 years is about 3 months, 0.5 years is about 6 months.
When to use this calculator
Calculate years of work experience for job applications and resumes. Track how long you've lived in a city, been married, or owned a home. Financial advisors compute years to retirement. Historians measure spans between historical events. Insurance companies determine policy duration. Genealogists calculate generations and lifespans in family trees.
Examples
From January 1, 2000 to January 1, 2025 is exactly 25 years.
From your birthdate to today gives your age in years, including a decimal for the months since your last birthday.
Common spans in years
How long familiar date ranges are when measured in years:
| Date range | Years |
|---|---|
| One week | 0.0191650 |
| One month (avg) | 0.0833402 |
| One year | 1 |
| One decade | 10 |
Frequently asked questions
How many years is 1,000 days?
About 2.74 years (1,000 ÷ 365.25).
Does it count leap years?
Yes. The 365.25-day average year accounts for one leap day every four years, so long spans stay accurate.
Why is my result a decimal?
A decimal shows the partial year: 2.5 years is 2 years and about 6 months.