How many days until my birthday?

Enter your birthday above to see the exact number of days left. If you'd rather count it yourself, the shortcut is to number today and your next birthday by day of the year (January 1 is day 1) and subtract. The steps and two worked examples are below.

How to count it by hand

Every date has a day number. Use the table to find the number of days that come before each month, then add the day of the month.

In a leap year, add 1 to every month from March onward.

The day number of a date is the "days before it" value plus the day of the month. October 13 is 273 + 13 = day 286. March 8 is 59 + 8 = day 67.

Example 1: your birthday is still ahead this year

Say today is October 13, 2026 and your birthday is December 20.

• Today: 273 + 13 = day 286
• Birthday: 334 + 20 = day 354
• Days left: 354 − 286 = 68

Example 2: your birthday already passed

Same today (October 13, 2026), but your birthday is March 8.

• Today: day 286
• Days left this year: 365 − 286 = 79 (2026 isn't a leap year)
• Birthday next year: 59 + 8 = day 67
• Days left: 79 + 67 = 146

You can check it the long way. From October 13, that's 18 days left in October, then 30 for November, 31 for December, 31 for January and 28 for February, plus the 8 days into March. 18 + 30 + 31 + 31 + 28 + 8 = 146.

Leap years change the totals by one day. Counting from October 13, 2027 to March 8, 2028 gives 79 + 31 + 29 + 8 = 147, because February 2028 has 29 days. The same dates a year earlier gave 146. In short: if the stretch you're counting includes a February 29, add 1; use 366 instead of 365 when the current year is a leap year and today is after February 28.

For a February 29 birthday, take today as October 13, 2027. Days left in 2027 are 365 − 286 = 79. February 29, 2028 is day 60 of that leap year. Total: 79 + 60 = 139. In the years without a February 29, pick February 28 or March 1 and use that date.

Counting by months instead

If you only need a rough idea, count whole months and adjust. From October 13 to March 13 is 5 months, which is 151 days. Your March 8 birthday comes 5 days earlier, so 146 again. It works, but month lengths vary from 28 to 31 days, which is why the day-of-year method is easier to get right.

Edge cases

• Birthday today: 0 days. Nothing to subtract.
• Birthday tomorrow: 1 day. "Days until" doesn't count today.
• February 29: the real date only exists every four years (see the example above). Most people use February 28 or March 1 in between.
• Time of day: all of the above counts whole days. If you want hours too, you'd count from midnight at the start of the birthday.

Let the app count it every day

Counting by hand is fine once. It's tedious for a list of people. Birthday Countdown is an iPhone app that does the subtraction for you and keeps it current. It's free for up to 5 birthdays.

1. In the Birthdays tab, tap the plus button (Add birthday).
2. On the New Birthday screen, enter a first name (the last name is optional) and pick the month and day. You can also add a note, choose groups and set reminders.
3. Tap Save Birthday. The list shows the days left for each birthday, and the next one sits at the top.
4. Add the Home Screen widget (small or medium) to see the next birthday without opening the app.
5. For reminders, choose the day itself, 1 day, 3 days or a week before, at the time you want.

Everything is stored on your iPhone and there's no account. It saves the day and month only, not the birth year, so it counts down to birthdays but doesn't work out ages. Premium removes the 5-birthday limit. See the full list of features on the Birthday Countdown app page.