Date Difference & Age Calculator
Find the exact time between two dates. Pick a start date and an end date, and you'll see the gap in years, months, and days, plus the total number of days and weeks. It also works as an age calculator — put a birth date in the first box and today's date in the second.
Enter values above to see the result.
What the calculator gives you
Pick two dates and you get:
- Difference — the gap as years, months, and days (the age-style answer).
- Total days — the exact number of calendar days between the dates.
- Total weeks — the same span counted in whole weeks, with any leftover days.
- Total whole months — how many complete months fit in the span.
A worked example
From January 1, 2024 to January 15, 2024 is 14 days — which also reads as 2 weeks. Pick a birth date like June 15, 1990 and an end date of September 20, 2024, and you'll get 34 years, 3 months, 5 days.
How it handles months
Months aren't all the same length, so "one month later" isn't a fixed number of days. This calculator counts whole calendar months first — January 15 to February 15 is one month whether February has 28 days or 29 — then adds the leftover days. When the end day-of-month is earlier than the start's, it uses the real length of the month it's completing, so end-of-month dates (like January 31) don't drift.
When you'll use it
Working out someone's exact age, counting down to a deadline or event, measuring how long you've held a job or lived somewhere, or figuring the number of days for interest, notice periods, or booking stays.
Frequently asked questions
How do I use this as an age calculator?
Put the birth date in the 'From date' box and today's date in the 'To date' box. The 'Difference' line — years, months, and days — is the person's age. The order of the two dates doesn't matter, so you can't get it backwards.
How is the years-months-days breakdown worked out?
It counts whole calendar months from the start date, then the leftover days. Because months have different lengths, it uses the real length of each month rather than a flat 30 days, so the breakdown lines up with the actual calendar. That's why an 'age' ticks over on the right day.
Does it count leap years correctly?
Yes. The day and week totals are exact calendar-day counts, so a span that crosses February 29 includes that extra day. For example, all of 2020 (a leap year) is 366 days, while all of 2021 is 365.
Are both the start and end dates included?
The result is the number of days from the start date to the end date. Two dates one day apart show 1 day. If you need to count both endpoints as full days (common for booking nights or event days), add one to the total.
Why does the breakdown sometimes show 0 years?
If the two dates are less than a year apart, the years figure is 0 and the gap shows in months and days instead. A span of exactly zero days shows '0 days' and a 'Same day' note.