Age Calculator: Exact Age in Years, Months & Days

How to use the age calculator

Type the birth date as YYYY-MM-DD.
Enter the end date or leave it blank for today.
Read the age and the total days.
Use the next-birthday countdown for planning.

How age is counted

Whole months = months between the two dates, without passing the end date
Years = whole months ÷ 12 (rounded down)
Days = end date − (birth date + whole months)

Month ends are clamped: 31 January plus one month is 28 or 29 February.

Worked examples

Each example below is generated by the same calculator you used above, so the working always matches the answer.

1990-05-15 → 2026-10-03

Answer36 years, 4 months, 18 days

13,290 days in total
About 1,898 weeks
Next birthday in 224 days

Step-by-step working 4 steps

1
Subtract year, month and day
```
2026-10-03 − 1990-05-15
```
2
Count whole months, then leftover days
Add whole months to the birth date (clamping to the end of shorter months) until the next month would pass the end date; the leftover days are counted directly.
3
Age
```
36 years, 4 months, 18 days
```
4
Total days between the dates
```
13,290 days
```

2000-01-31 → 2000-03-01

Answer0 years, 1 months, 1 days

30 days in total
About 4 weeks
Next birthday in 336 days

Step-by-step working 4 steps

1
Subtract year, month and day
```
2000-03-01 − 2000-01-31
```
2
Count whole months, then leftover days
Add whole months to the birth date (clamping to the end of shorter months) until the next month would pass the end date; the leftover days are counted directly.
3
Age
```
0 years, 1 months, 1 days
```
4
Total days between the dates
```
30 days
```

2012-02-29 → 2026-02-28

Answer14 years, 0 months, 0 days

5,113 days in total
About 730 weeks
Next birthday in 1 days

Step-by-step working 4 steps

1
Subtract year, month and day
```
2026-02-28 − 2012-02-29
```
2
Count whole months, then leftover days
Add whole months to the birth date (clamping to the end of shorter months) until the next month would pass the end date; the leftover days are counted directly.
3
Age
```
14 years, 0 months, 0 days
```
4
Total days between the dates
```
5,113 days
```

Common mistakes to avoid

Subtracting years only

Birth year subtracted from this year overstates age if the birthday has not happened yet.

Ignoring leap years

Total days must account for 29 February; the calculator counts calendar days directly.

Wrong date format

Use year-month-day with leading zeros, e.g. 2026-03-07.

Frequently asked questions

Does it work for dates in the past?

Yes. Set the end date to any day on or after the birth date.

Is my date stored?

No. It is processed in your browser and not sent anywhere.