Age Calculator — Calculate Age in Years, Months and Days (Online)

Age results

Exact age

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Years, months and days.

Total years (approx.)

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Age in years with decimals.

Total months

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Full months between the two dates.

Total days

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Number of calendar days lived.

Enter your date of birth above and optionally a second date to see a full age breakdown.

Free age calculator: from birthdate to age in one click

This online age calculator turns your date of birth into a precise age in years, months and days. Instead of counting years on your fingers or guessing your age on a specific date, you can type the dates once and let the tool do the calendar math for you.

Many people search for long phrases like “how to calculate my age in years months and days from date of birth” or “age difference between two dates calculator online”. This page is built exactly for those real-world questions: simple inputs, clear outputs and detailed explanations, without ads or distractions.

How this age calculator works step by step

The age calculator works like a human doing careful date subtraction, but with all the edge cases handled for you. Behind the scenes it follows three main steps:

1. Convert the dates
   - Birth date → (year₁, month₁, day₁)
   - Target date → (year₂, month₂, day₂)

2. Raw difference
   years  = year₂  − year₁
   months = month₂ − month₁
   days   = day₂   − day₁

3. Adjust negatives
   if days < 0:
       days   += days in the previous month
       months -= 1

   if months < 0:
       months += 12
       years  -= 1

This produces the familiar “X years, Y months, Z days” format used on official documents and application forms. On top of that, the calculator also counts the total days between the two dates and converts those days into approximate years with decimals.

Why use an online age calculator instead of doing it by hand?

It sounds easy to subtract one date from another, but the details are tricky: months have different lengths, leap years add extra days, and many forms require your exact age on a particular date. Common use cases include:

Checking the eligibility age for a school, exam or competition.
Confirming your age for visa and immigration forms.
Finding your age at a future event date (wedding, travel, start of a job).
Calculating the age gap in a relationship or between siblings.
Tracking personal milestones like “10,000 days old” or “exactly 30.5 years old”.

Rather than counting calendar squares or searching multiple websites, this single date of birth to age calculator gives you years, months, days, total months and total days in one place.

How to use the age calculator (simple tutorial)

1. Enter your date of birth

In the first line of the form, type your birth day, month and year. Always use a four-digit year (for example, 1992 instead of 92).

2. Choose the date you want to calculate age at

In the second line you can enter the date at which you want to know your age. If you leave it empty, the calculator automatically uses today’s date.

You can set any date in the past or future. This makes the tool a flexible “age on a specific date calculator” rather than just a basic age-today checker.

3. Click “Calculate age”

Press the green button and the page will show:

Your exact age in years, months and days.
Your age in decimal years (for example 23.75 years).
Total months lived between the two dates.
Total days lived as a simple integer.

Examples: from date of birth to exact age

Example 1 — Quick age today

Date of birth: 12 / 03 / 2000

Age at date of: today

If today is 16 / 11 / 2025, the calculator shows something like:

Age: 25 years, 8 months, 4 days
Total years (approx.): 25.68
Total months: 308
Total days: 9,380+ (exact number based on leap years).

Example 2 — Age on exam day

Imagine you were born on 5 September 2007 and you are filling a form that asks for your age on the exam date of 15 June 2024.

Enter your birth date in the first row and the exam date in the second row. The tool becomes an “age calculator for exam eligibility” and outputs your age exactly on that day, which you can copy straight into the form.

Example 3 — Age difference between two people

You can also use the calculator to compare two ages. First, calculate your own age for a certain date. Then change the birth year, month and day to the other person’s details and calculate again.

Subtracting the results gives you the age gap in years and days, which is often useful for sports categories or “age gap relationship” curiosity.

What do “years”, “months” and “total days” really mean here?

Age can be expressed in several ways. This calculator provides four different but related views of the same date difference:

Exact age (years, months, days) — this is the official style used on many government and immigration forms. It is based on the real calendar, not on an approximate number of days.
Total years (approximate) — here the tool divides total days by the average length of a year (about 365.2425 days) to get a decimal value such as 21.52 years. This is handy when you need an age for charts or statistics.
Total months — counts how many full months fit between the two dates. This is useful for baby milestones and some subscription or contract calculations.
Total days — a simple integer telling you how many days you have been alive between the two dates. People often enjoy seeing when they hit 10,000 days or other milestones.

Tips for using your age result on forms and applications

Check the required format

Some forms want only your birthdate, others want “completed years”, and some ask for an exact breakdown. Read the wording carefully:

If it says “age in completed years”, only use the whole years part. For example, 21 years 8 months → write 21.
If it says “age as on [date]”, enter that date as the “age at date of” in the calculator, then copy the result.
If it says “date of birth (DD/MM/YYYY)”, just use your birthdate, which this tool helps you verify.

Common mistakes to avoid

Mixing day and month (for example 04/05 vs 05/04) when the format is not clear.
Using a two-digit year like 05 instead of 2005.
Ignoring leap years when calculating manually.

Frequently asked questions about this age calculator

Does the calculator work for future dates?

Yes. Set the “age at date of” fields to any future day, month and year to see how old you will be on that date. This is useful for planning events, retirement or visa timelines.

What happens if I enter a date before my birthdate?

If the target date is earlier than the date of birth, the calculator will not show a negative age. Instead, it simply warns you and clears the result so you can correct the input.

Is this age calculator accurate enough for official use?

The underlying date difference is based on the same calendar rules that operating systems and browsers use, so the result is very accurate. However, always follow the exact instructions of the institution (school, embassy, employer) if they specify a particular method of counting age.

Does time of day matter for this calculator?

No. This is a pure calendar age calculator. It treats both dates as full days and does not try to calculate hours or minutes. That makes it simple, stable across time zones, and perfect for forms that only care about dates.

Will my date of birth be stored?

The calculator runs entirely in your browser. Once you close the page or refresh, the values disappear. It is a convenient “age calculator without login or registration”.

Age Calculator — Exact Age in Years, Months and Days