Age Calculator
Enter a date of birth to get an exact age in years, months and days. You can also set the second date to work out how old someone was, or will be, on any other day.
Enter a date of birth
In months
0
Whole months lived
In weeks
0
Whole weeks lived
In days
0
Total days lived
Every age in months, weeks and days
Open the band you need. Each row gives an age in whole years and the same age written as months, weeks and days.
Under 21Ages under 21 written as months, weeks and days.
| Age | Months | Weeks | Days |
|---|---|---|---|
| 1 year | 12 months | 52 weeks | about 365 |
| 2 years | 24 months | 104 weeks | about 731 |
| 3 years | 36 months | 157 weeks | about 1,096 |
| 4 years | 48 months | 209 weeks | about 1,461 |
| 5 years | 60 months | 261 weeks | about 1,826 |
| 6 years | 72 months | 313 weeks | about 2,192 |
| 7 years | 84 months | 365 weeks | about 2,557 |
| 8 years | 96 months | 417 weeks | about 2,922 |
| 9 years | 108 months | 470 weeks | about 3,287 |
| 10 years | 120 months | 522 weeks | about 3,653 |
| 11 years | 132 months | 574 weeks | about 4,018 |
| 12 years | 144 months | 626 weeks | about 4,383 |
| 13 years | 156 months | 678 weeks | about 4,748 |
| 14 years | 168 months | 730 weeks | about 5,114 |
| 15 years | 180 months | 783 weeks | about 5,479 |
| 16 years | 192 months | 835 weeks | about 5,844 |
| 17 years | 204 months | 887 weeks | about 6,209 |
| 18 years | 216 months | 939 weeks | about 6,575 |
| 19 years | 228 months | 991 weeks | about 6,940 |
| 20 years | 240 months | 1,044 weeks | about 7,305 |
21 to 40Ages 21 to 40 written as months, weeks and days.
| Age | Months | Weeks | Days |
|---|---|---|---|
| 21 years | 252 months | 1,096 weeks | about 7,670 |
| 22 years | 264 months | 1,148 weeks | about 8,036 |
| 23 years | 276 months | 1,200 weeks | about 8,401 |
| 24 years | 288 months | 1,252 weeks | about 8,766 |
| 25 years | 300 months | 1,304 weeks | about 9,131 |
| 26 years | 312 months | 1,357 weeks | about 9,497 |
| 27 years | 324 months | 1,409 weeks | about 9,862 |
| 28 years | 336 months | 1,461 weeks | about 10,227 |
| 29 years | 348 months | 1,513 weeks | about 10,592 |
| 30 years | 360 months | 1,565 weeks | about 10,958 |
| 31 years | 372 months | 1,618 weeks | about 11,323 |
| 32 years | 384 months | 1,670 weeks | about 11,688 |
| 33 years | 396 months | 1,722 weeks | about 12,053 |
| 34 years | 408 months | 1,774 weeks | about 12,419 |
| 35 years | 420 months | 1,826 weeks | about 12,784 |
| 36 years | 432 months | 1,878 weeks | about 13,149 |
| 37 years | 444 months | 1,931 weeks | about 13,514 |
| 38 years | 456 months | 1,983 weeks | about 13,880 |
| 39 years | 468 months | 2,035 weeks | about 14,245 |
| 40 years | 480 months | 2,087 weeks | about 14,610 |
41 to 65Ages 41 to 65 written as months, weeks and days.
| Age | Months | Weeks | Days |
|---|---|---|---|
| 41 years | 492 months | 2,139 weeks | about 14,975 |
| 42 years | 504 months | 2,191 weeks | about 15,341 |
| 43 years | 516 months | 2,244 weeks | about 15,706 |
| 44 years | 528 months | 2,296 weeks | about 16,071 |
| 45 years | 540 months | 2,348 weeks | about 16,436 |
| 46 years | 552 months | 2,400 weeks | about 16,802 |
| 47 years | 564 months | 2,452 weeks | about 17,167 |
| 48 years | 576 months | 2,505 weeks | about 17,532 |
| 49 years | 588 months | 2,557 weeks | about 17,897 |
| 50 years | 600 months | 2,609 weeks | about 18,263 |
| 51 years | 612 months | 2,661 weeks | about 18,628 |
| 52 years | 624 months | 2,713 weeks | about 18,993 |
| 53 years | 636 months | 2,765 weeks | about 19,358 |
| 54 years | 648 months | 2,818 weeks | about 19,724 |
| 55 years | 660 months | 2,870 weeks | about 20,089 |
| 56 years | 672 months | 2,922 weeks | about 20,454 |
| 57 years | 684 months | 2,974 weeks | about 20,819 |
| 58 years | 696 months | 3,026 weeks | about 21,185 |
| 59 years | 708 months | 3,078 weeks | about 21,550 |
| 60 years | 720 months | 3,131 weeks | about 21,915 |
| 61 years | 732 months | 3,183 weeks | about 22,280 |
| 62 years | 744 months | 3,235 weeks | about 22,646 |
| 63 years | 756 months | 3,287 weeks | about 23,011 |
| 64 years | 768 months | 3,339 weeks | about 23,376 |
| 65 years | 780 months | 3,392 weeks | about 23,741 |
66 to 100Ages 66 to 100 written as months, weeks and days.
| Age | Months | Weeks | Days |
|---|---|---|---|
| 66 years | 792 months | 3,444 weeks | about 24,107 |
| 67 years | 804 months | 3,496 weeks | about 24,472 |
| 68 years | 816 months | 3,548 weeks | about 24,837 |
| 69 years | 828 months | 3,600 weeks | about 25,202 |
| 70 years | 840 months | 3,652 weeks | about 25,568 |
| 71 years | 852 months | 3,705 weeks | about 25,933 |
| 72 years | 864 months | 3,757 weeks | about 26,298 |
| 73 years | 876 months | 3,809 weeks | about 26,663 |
| 74 years | 888 months | 3,861 weeks | about 27,029 |
| 75 years | 900 months | 3,913 weeks | about 27,394 |
| 76 years | 912 months | 3,965 weeks | about 27,759 |
| 77 years | 924 months | 4,018 weeks | about 28,124 |
| 78 years | 936 months | 4,070 weeks | about 28,490 |
| 79 years | 948 months | 4,122 weeks | about 28,855 |
| 80 years | 960 months | 4,174 weeks | about 29,220 |
| 81 years | 972 months | 4,226 weeks | about 29,585 |
| 82 years | 984 months | 4,279 weeks | about 29,951 |
| 83 years | 996 months | 4,331 weeks | about 30,316 |
| 84 years | 1,008 months | 4,383 weeks | about 30,681 |
| 85 years | 1,020 months | 4,435 weeks | about 31,046 |
| 86 years | 1,032 months | 4,487 weeks | about 31,412 |
| 87 years | 1,044 months | 4,539 weeks | about 31,777 |
| 88 years | 1,056 months | 4,592 weeks | about 32,142 |
| 89 years | 1,068 months | 4,644 weeks | about 32,507 |
| 90 years | 1,080 months | 4,696 weeks | about 32,873 |
| 91 years | 1,092 months | 4,748 weeks | about 33,238 |
| 92 years | 1,104 months | 4,800 weeks | about 33,603 |
| 93 years | 1,116 months | 4,853 weeks | about 33,968 |
| 94 years | 1,128 months | 4,905 weeks | about 34,334 |
| 95 years | 1,140 months | 4,957 weeks | about 34,699 |
| 96 years | 1,152 months | 5,009 weeks | about 35,064 |
| 97 years | 1,164 months | 5,061 weeks | about 35,429 |
| 98 years | 1,176 months | 5,113 weeks | about 35,795 |
| 99 years | 1,188 months | 5,166 weeks | about 36,160 |
| 100 years | 1,200 months | 5,218 weeks | about 36,525 |
Why an age is not just a subtraction
Taking one year from another gets you close and is often wrong by a year. Someone born in December 1990 is not 35 in January 2026, they are 35 only after their December birthday.
The proper method works in three steps. Count whole years since the birth year, adjusting down if the birthday has not happened yet. Then count whole months since that birthday. Then count the days left over.
The days step is where hand calculations fail, because you have to borrow the length of the previous month. Borrowing a flat 30 puts every result in a 31-day month a day out.
Leap years and the 29 February question
A year is 365 days, except every fourth year when it is 366. The average is 365.25, which is why an age in days is never a round multiple and why the chart above says about.
The rule has an exception most people never need: century years are not leap years unless they divide by 400. So 1900 had no 29 February and 2000 did.
People born on 29 February have a birthday only every four years. In most countries the law treats them as turning a year older on 1 March in other years, though some jurisdictions say 28 February. Either way the month and day counts here are unaffected.
The other side of counting time
An age is time that passed whether you did anything with it or not. Working hours are the opposite: they only count if someone wrote them down, and the ones nobody wrote down are the ones that go unbilled.
If you came here for date arithmetic rather than an age, the date difference calculator counts days and working days between any two dates.
And if the question is really about hours rather than years, the hours calculator works out the gap between two times, while the hours to days converter scales it up.
Frequently asked questions
Common queries and answers about the age calculator.
- How do I work out my exact age?
- Count the years since you were born, then the months since your last birthday, then the days since that. The calculator above does it, including the leap years.
- How old would a 14 year old be in months?
- A 14 year old is 168 months old, because 14 times 12 is 168. In days it is about 5,114.
- How many months old is a 10 year old?
- 120 months. Multiply the age in years by 12 to get whole months.
- How many days old am I if I am 30?
- About 10,958 days at 30 years old. The exact figure depends on how many leap years fell in that span.
- Why does my age in days look uneven?
- Leap years. A year is 365 days most of the time and 366 every fourth year, so an average year is 365.25 days rather than a round number.
- How is age counted if I was born on 29 February?
- In most countries you legally turn a year older on 1 March in non-leap years, though some treat it as 28 February. The calculator counts the full months either way.
- Can I work out my age on a future date?
- Yes. Change the second date to any day you like and it will tell you how old you will be then.
- How many weeks are in a year?
- 52 weeks and one day, or two days in a leap year. That is why 52 times a whole number of years drifts from the real week count.
- Does this calculator store my date of birth?
- No. It runs entirely in your browser and nothing you type is sent anywhere or saved.
- Why do months not all have the same length?
- Months run from 28 to 31 days, so a month of age means a calendar month rather than a fixed number of days. The calculator borrows the real month length.
Tired of doing this by hand?
TimeTracker captures every hour automatically and turns it into timesheets, invoices, and live profitability.