1. Pick the dates
Pick a starting date (e.g. a birthday) and an end date (defaults to today).
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Age & Date Calculator
Age and the gap between two dates.
Pick both dates to see the breakdown.
Dates are calculated in this browser tab. Nothing is uploaded.
How it works
2. Read the breakdown
The calculator shows the exact gap as years + months + days, plus rolled-up totals.
3. Bonus: next birthday
When the start date is a birthday, you also see how many days until the next one.
About the Age & Date Calculator tool
The Age & Date Calculator works out the exact span between two dates. Enter a birthday (or any start date) and an end date — today by default — and it returns the gap as years, months, and days, mirroring how a passport or doctor would state an age, along with rolled-up totals in weeks, days, and hours. When the start date is a birthday, it also shows how many days remain until the next one.
Use it to find your precise age, count how long until or since an event, check the days between two milestones, or count down to a deadline (the breakdown goes negative when the end date is in the future). Leap years are handled by real date arithmetic, so February 29 birthdays are treated correctly. The whole calculation runs in your browser — the dates you enter never leave your device — and the tool is free, needs no account, and works offline once loaded.
Frequently asked questions
How are years and months counted?
Years are counted as full calendar years passed. Months and days fill in the remainder, mirroring how a passport or doctor would describe an age.
Are leap years handled?
Yes. Leap years are handled by date arithmetic — February 29 birthdays roll to February 28 in non-leap years for the next-birthday calculation.
Can I count down to a future date?
If the end date is before the start date, the breakdown shows negative values so you can use it to count down to a future date too.
Are the dates sent anywhere?
No. The calculation is local — the dates you enter never leave your device.