How the age calculator works
Last updated 10 November 2026
Age in years is easy. Age in years, months and days, and the days to the next birthday, take a little more care.
How it works
- Whole months are counted forward from the birth date.
- The leftover days complete the answer.
When you need an exact age
A birthday count in whole years is enough for most chats. Forms, school applications, insurance quotes and sports leagues often want more: the age on a particular date, or in years, months and days. This tool gives all of those from one date of birth.
- School and crèche intake dates, where the cut-off is a set day of the year
- Sports and age-group entries that use age on a fixed date
- Legal and policy thresholds that depend on how old someone was on a given day
- Milestones such as a child's age in months
Age on another date
The second date box lets you ask a different question: how old was someone on a past date, or how old will they be on a future one. Leave it as today for the current age. Change it to a closing date for an application, a race day or the start of a school year to see the age that counts on that day.
How months and days are counted
The calculator counts whole months forward from the date of birth, then counts the leftover days. This is the way most people count: born on the fifteenth of a month, you turn one month old on the fifteenth of the next month. If a month has no matching day, for example a birth on the thirty-first and a month that ends on the thirtieth, the count uses the last day of that month.
Leap-year birthdays
People born on 29 February have a birthday only in leap years. In other years this tool counts their birthday on 28 February, which is the simplest and most common convention. Some legal settings pick 1 March instead, so check the rule that applies to your form before you rely on a date.
What this does not cover
The tool does not decide whether someone meets an age rule, because those rules differ between schools, employers, insurers and laws. It gives the age. You compare it with the rule. Your device clock supplies today's date, so if the date on your phone is wrong, the answer will be wrong too.
Related tools
To count the days between two dates that are not birthdays, use the date difference calculator. For counting down to a deadline or an exam, see the exam countdown.
A note on accuracy
The result is only as good as the dates you type in. Check the day and month are in the right order, because a swapped day and month gives a very different age.
Things to watch
- The date used for today comes from your device.
Nothing is stored.
Like every tool on MoneyMzansi, this one runs entirely in your browser. There is no account, no upload and no sign-up, so it keeps working even if your connection drops once the page has loaded.