Age Calculator
Calculate completed years, elapsed calendar days and the next birthday date from a birth date and your device’s current local date.
Start using
See completed years, elapsed calendar days, full weeks and the next birthday together. Full weeks are elapsed days divided by seven, rounded down.
2026-08-29 → 2026-09-05: 7 / 7 = 1
What the age result means
The calculator compares one birth date with today's local date on your device. Completed years increase only after this year's birthday. Elapsed calendar days count date boundaries, not the current day as another full day. There is no selectable reference date or birth time.
Repeatable boundary check
If the device date is September 5, 2026, a September 6, 2000 birth gives 25 completed years; September 5 gives 26. In a non-leap year a February 29 anniversary is treated as February 28. The day calculation normalizes the two calendar dates, avoiding daylight-saving-hour distortion.
Reading the extra labels
The Western sign uses fixed month/day boundaries. The Chinese animal uses the Gregorian birth year, not the lunar new-year boundary; a January or early-February birth can therefore differ from a traditional lunar-calendar reading.
Limits and checks
Use the relevant authority's cutoff and local age rule for legal, school or benefit decisions. If the result seems one year off, recheck the entered birthday and today's device date. This result is not medical or legal advice.
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