About the Birthday Calculator
Enter your date of birth and this calculator counts down to your next birthday, tells you which day of the week it lands on and how old you'll be. It also shows the day of the week you were born, how many days and weeks you have been alive, the date of your half birthday and when your next big round-number birthday falls. If you were born on 29 February you can choose whether to celebrate on 28 February or 1 March in other years. Today's date comes from your own device.
Updated October 2026
How to use the Birthday Calculator
- 1Enter your date of birth.
- 2If you were born on 29 February, choose 28 February or 1 March.
- 3Read the days until your next birthday.
- 4See the weekday you were born and other facts below.
- 5Copy the countdown to share it.
Fun facts the calculator finds
Beyond the countdown, the tool shows the weekday of your birth, which is the basis of the old rhyme Monday's child is fair of face. It also counts your days alive, so you can spot milestones like your 10,000th day, which arrives at about 27 years and 4 months old.
Planning a party
The next birthday row tells you whether the day falls on a weekend, which helps when booking venues. If it lands midweek, many people celebrate on the nearest Saturday; check the dates either side in a calendar.
- Countdown in days
- Weekday of the next birthday
- Age you'll be turning
- Your next round-number birthday
Leap-day birthdays
About one person in 1,461 is born on 29 February. In common years the UK and Hong Kong treat 1 March as the legal birthday for things like coming of age, while many other places use 28 February. The option in the calculator lets you pick whichever you celebrate.
How the dates are worked out
The calculator compares calendar dates rather than hours, so time zones and daylight saving don't shift the answer by a day. Ages and day counts include all leap years between your birth and today.
Milestones worth celebrating
Some people celebrate unusual milestones: being 1,000 weeks old (about 19 years and 2 months), turning 10,000 days, or a golden birthday when you turn the same age as the day of the month you were born. The days and weeks alive rows make these easy to spot. The next round birthday row shows when you will reach your next decade, which is handy for planning a bigger party well ahead.
On your phone
Bookmark the page and the countdown updates every time you open it. Counting down to a birthday is a start; there is more to know about the date itself. Use the Age Calculator for exact years, months and days, the Zodiac Sign Calculator to see which sign it falls under, and the Day of the Week Calculator to learn which weekday you were born on.
Features
- Countdown to your next birthday
- Weekday of your next birthday
- Day of the week you were born
- Days and weeks alive
- Half birthday and next round birthday
- Leap-day birthdays handled
Frequently asked questions
How many days until my birthday?
Enter your date of birth and the tool counts the days from today to your next birthday, using your device's date.
What day of the week was I born?
The calculator shows it under the countdown. Someone born on 15 May 1990, for example, was born on a Tuesday.
When is my half birthday?
Six months after your birthday. If that month is shorter, the calculator uses the last day of the month, so a 31 August birthday has a half birthday on 28 or 29 February.
What if I was born on 29 February?
In years without 29 February you can choose to count your birthday as 28 February or 1 March. Countries differ on which is the legal date.
How many days old am I?
The days-alive row counts every day from your birth date to today, including leap days.
Is my date of birth stored?
No. The calculation happens in your browser and nothing is sent or saved.