What is the fastest way to get my exact age?

Use the age calculator at `/w/age-calculator`. It runs in your browser, requires no data from you, and gives the exact result instantly. The manual method above is useful for understanding why the tool works and for checking its output.

Why do I get a different age if I count from my birth date to today versus subtracting years?

Because year subtraction alone ignores whether your birthday has passed. The birthday check is the missing step. Counting days from birth to today and then converting to years, months, and days is the most reliable manual method.

How do I calculate age for someone born on 29 February?

In common years, a person born on 29 February has no birthday. Standard convention is that age increments on 28 February or 1 March, depending on the jurisdiction. The age calculator treats 28 February as the birthday in common years.

Is age at last birthday the same as chronological age?

Yes. Chronological age normally means completed years, months, and days since birth, which is exactly age at last birthday. Legal documents and everyday use nearly always mean this.

What is the difference between age at last birthday and age nearest birthday?

Age at last birthday is the number of whole years since birth. Age nearest birthday rounds to the closest birthday. For a person born on 20 March, on 10 July the nearest birthday is still the past one (26), but on 15 September it would be the future one (27).

Does the age calculator handle leap years correctly?

Yes. The JavaScript Date object and the backend both use the Gregorian leap year rule: years divisible by 4 are leap years, except century years not divisible by 400. The tool accounts for this automatically.

How to Calculate Your Exact Age (Years, Months, Days)

Your exact age in completed years, months, and days is a simple date subtraction problem, but only if you account for uneven month lengths, the birthday check, and leap years. Here is the method that works every time.

How many years, months, and days have you lived?

Someone born on 20 March 2000 is 26 years old on 1 October 2026, not 27. Their 27th birthday has not arrived yet. Chronological age always means completed calendar units: whole years first, then whole months beyond the last birthday, then remaining days. This is "age at last birthday," and it is the standard everyday meaning.

How to work out your age by hand

Take a person born on 20 March 2000 who wants their age on 10 July 2026.

Step 1: Find completed years. Subtract the birth year from the current year: 2026 minus 2000 equals 26. Check whether the birthday (20 March) has already happened in 2026. It has: 20 March comes before 10 July. 26 is correct. If the date were 1 March 2026, the birthday would not yet have passed, and the correct age would be 25.

Step 2: Count the extra months. From the most recent birthday (20 March 2026), count whole months forward. March to April is one month, April to May is two, May to June is three. Stop before the current date. On 10 July, only 20 days of July have passed, so the last fully completed month is June. That gives 3 complete months (April, May, June).

Step 3: Count the extra days. From the last completed month (20 June) to the current date (10 July), count the days. June has 30 days, so from 20 June to 30 June is 10 days, then 1 July to 10 July is 10 days. Total: 20 days.

Result: 26 years, 3 months, and 20 days.

When you need to carry across a month boundary

Change one number. Birth date: 20 March 2000. Current date: 10 March 2026.

Completed years: 26 (the birthday has passed). Extra months: zero, because the birthday was only 10 days ago and no full month has been completed. Extra days: count from the last birthday directly. From 20 March 2025 to 10 March 2026 is 0 years, 11 months, and 20 days.

The carrying method handles it correctly: if today's day (10) is earlier than your birth day (20), take one month from the month count and add that month's days to today's day. The month you take from is the one before the current month, which is February 2026 (28 days). So days become 10 plus 28 equals 38. Then subtract the birth day: 38 minus 20 equals 18 days. Months become zero (you carried one). Years remain 26.

Why subtracting years alone fails

The single most common error in age calculation is subtracting birth year from current year and stopping. It is wrong for anyone whose birthday has not yet arrived in the current year. Roughly half the population at any given moment is affected. A person born on 31 December 2000 appears 26 years old on 1 January 2026 if you only subtract years, but they are actually 25 until 31 December. The birthday check is not optional.

How month lengths change the answer

When you carry across a month boundary, the number of days you add depends entirely on the month you are taking from. Carrying across January adds 31 days. Carrying across February adds 28 days in a common year, 29 in a leap year. Carrying across April, June, September, or November adds 30 days. The assumption that all months have 30 days is the second most common error. It produces wrong results whenever February or a 31-day month is involved.

How to get your exact age without sending data anywhere

Open the age calculator at /w/age-calculator. Type your birth date. The arithmetic runs in your browser: JavaScript handles the date logic, including leap year rules and month lengths. No birth date leaves your device. Check the result against the manual method above to confirm the tool matches standard calendar arithmetic.

Age at last birthday vs age next birthday vs age nearest birthday

Everyday age is "age at last birthday," meaning completed years. Two other conventions exist. "Age next birthday" is the age you will reach on your next birthday, used in some insurance policies for calculating premiums. "Age nearest birthday" rounds to the closest birthday, used in some medical contexts and pension schemes. If your birth date is 20 March 2000 and today is 10 July 2026, your age at last birthday is 26, age next birthday is 27, and age nearest birthday is 26 (because 10 July is closer to 20 March 2026 than to 20 March 2027). The calculator defaults to age at last birthday, which is what most people mean by "how old am I."

Common mistakes people make calculating age

Mistake 1: Skipping the birthday check. Already covered. Always compare the month and day of birth to the current month and day before subtracting years.

Mistake 2: Treating all months as 30 days. This error compounds when carrying is needed. Look up the actual number of days in the month you are taking from. February is the most common trap.

Mistake 3: Ignoring leap days in day-level totals. If you are calculating total days lived, missing leap days underestimates. Over 80 years, the error is about 20 days.

Mistake 4: Confusing date formats. A date written as 03/04/2000 is 3 April in the UK and 4 March in the US. Always write months as names to avoid ambiguity.

Mistake 5: Using 365.2425 days per year for exact day counts. The Gregorian average year is 365.2425 days, but for exact age in days between two specific dates, count the actual calendar days. Multiplying years by 365.2425 gives an average, not an exact answer.