Age Calculator
Turns a list of dates of birth into exact ages, as at today or any date you name.
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Processing happens locally in your browser.
What you paste or load is processed by this page and is not uploaded to a server. Nothing is stored unless you use a control that says it stores something, and you can clear anything this site has kept from the privacy page.
How to use this tool
- Paste the dates of birth, one per line.
- Set the "as at" date if you need ages at a cut-off rather than today. Leave it blank for today.
- Select Calculate age.
- Use the Years column for an eligibility check and the exact breakdown for anything that has to be defensible.
What age calculator does
Age is a calendar calculation, not a division. Somebody born on 1 March 2000 is exactly twenty-six on 1 March 2026 regardless of how many leap days fell in between, which is why this page counts whole years and months rather than dividing elapsed days by 365.25. Both figures are shown, because the day total is the one an eligibility rule sometimes wants.
The "as at" setting is the part that makes this useful for real work rather than curiosity. Ages for an eligibility check, a policy renewal or a cohort analysis are almost never wanted as at today — they are wanted as at a cut-off date, and setting one recalculates every row against it.
Frequently asked questions
By calendar, not by division. It counts complete years from the date of birth, then complete months, then the remaining days — the same way a person would. Dividing elapsed days by 365.25 gives a different and slightly wrong answer near a birthday, which is exactly when it matters.
Their anniversary is shown on 28 February in a common year. That is the convention databases use and the one most legal definitions follow, though a few jurisdictions say 1 March — if a rule depends on it, check the rule rather than the tool.
Yes, and it is the main reason this page exists. Set the "as at" date and every row is recalculated against it, which is what an eligibility cut-off, a policy renewal date or a historical cohort analysis actually needs.
The calculation is local and nothing is transmitted. But dates of birth are personal data under GDPR and most equivalent regimes, so apply your own policy: the fact that a tool does not upload them does not by itself make copying them out of a system acceptable.