# Age Calculator

> Work out exact age in years, months and days — plus total days and the next birthday.

To calculate age, enter a date of birth and optionally a reference date. The result gives exact years, months and days, using real calendar month lengths rather than a 30-day approximation, plus totals in weeks, days and hours and a countdown to the next birthday.

**URL:** https://convertto.tech/t/age-calculator
**Category:** Date & Time Tools (https://convertto.tech/c/date-time-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Enter or paste your date of birth.
2. Enter or paste your age on this date.
3. The result appears immediately — copy or download it.

## FAQ

### How is age calculated across a leap day?

By calendar, not by dividing days by 365.25. Someone born on 29 February has their legal birthday on 28 February or 1 March depending on jurisdiction, but their age still increments once a year.

### Why does my age differ by a day in some tools?

Timezone. If the calculation uses UTC and you are west of it, your local date can be a day behind — which changes the answer around a birthday. This tool works in UTC consistently so the result is stable.

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