Age & date calculator
Age and the gap between two dates.
Pick both dates to see the breakdown.
Everything runs in your browser. Nothing is uploaded.
How it works
Pick the dates
Pick a starting date (e.g. a birthday) and an end date (defaults to today).
Read the breakdown
The calculator shows the exact gap as years + months + days, plus rolled-up totals.
Bonus: next birthday
When the start date is a birthday, you also see how many days until the next one.
Questions
What does this tool do?
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.
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.