Age Calculator

How old are you, exactly? Forms ask for it constantly, schools and competitions set cut-offs by it, and ‘about thirty’ is not good enough when a deadline depends on the precise day. Our free age calculator works out an exact age from any date of birth: completed years, months and days, the total number of days lived, and how many days remain until the next birthday. You can also calculate the age on any specific past or future date, which is exactly what school admissions, sports leagues and eligibility checks require.

Quick Answer: Enter a date of birth and the calculator shows the exact age in years, months and days, total days lived, and a countdown to the next birthday. You can also check age on any chosen date.

Free Online Tool

Exact age, total days lived and next-birthday countdown.

Date of birth

Age at date (default: today)

Table of Contents

How to Use the Age Calculator

Enter the date of birth using the date picker.
Leave the 'age at date' field as today, or pick another date to check age at an admission deadline, exam or event.
Read the exact age in years, months and days at the top of the results.
Check the bonus figures: total days lived, day of the week of birth and days until the next birthday.
Try another date to compare ages for siblings, students or team members.

Key Features

Precise calendar arithmetic that handles leap years and month lengths correctly.
Age-at-a-date mode for deadlines like school entry, exams and competition eligibility.
Total days lived and next-birthday countdown included automatically.
Tells you the weekday the person was born, a detail everyone enjoys.
Works for births from the 1900s to today, privately in your browser.

Best Practices and Tips

For official forms, age is almost always counted as completed years on the stated cut-off date; use the age-at-date mode to match the rule exactly.
If a deadline falls on the birthday itself, the person is usually counted as the new age from the start of that day, but always confirm the organisation's wording.
Save the total-days figure for milestone fun: 10,000 days old happens at about 27 years and 4 months.
When checking a whole class or team, keep a simple list and process each date of birth in turn; each calculation is a fresh page state.

Common Mistakes to Avoid

Estimating age by subtracting years only, which is wrong for nearly half the year whenever the birthday has not happened yet.
Swapping day and month on dates written in different formats (US month-first versus most of the world); the date picker avoids this entirely.
Forgetting that a person born on 29 February celebrates on 28 February or 1 March in common years, which can matter for strict eligibility rules.

Frequently Asked Questions

How does the calculator work out months and days?

It counts complete years first, then complete months from the last birthday, then the remaining days, borrowing the correct number of days from the preceding month. This is the same calendar method official age calculations use.

What is my age in days?

The results show your total days lived. It is simply the number of midnights you have passed since birth, including every leap day you have lived through.

Can I calculate the age of someone born before 1900 or in the future?

Dates from the 1800s onward work fine. A future 'birth' date compared with today produces a negative interval, which the tool flags so you can correct the input.

Why do some forms ask for age on 1 September or another fixed date?

Organisations use a single reference date so everyone in a cohort is judged identically, regardless of when they submit the form. Enter that reference date in the 'age at date' field to replicate their calculation exactly.

Is my date of birth stored anywhere?

No. The calculation runs in your browser; the dates you enter never leave your device.