Age Calculator: Calculate Age from Date of Birth

The tool

Your online age calculator

Enter a date of birth, leave the reference date empty for today, and the milestones appear in an instant, along with the next birthday and the calculation history.

Age Calculator

Online Productivity, Office & Documents

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Shortcuts: Ctrl + Enter calculate

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Date of birth

YYYY-MM-DD format, entered with your browser's calendar.

Reference date

Leave empty to calculate from today.

Example dates

Click an example: the date of birth is filled in and the calculation starts right away.

Calculated age

—

Milestone	Value
Full years	—
Extra months	—
Extra days	—
Total age in days	—
Weeks elapsed	—
Hours lived	—
Day of birth	—
Next birthday	—
Days until birthday	—
Leap years crossed	—

How this age is calculated

Full years are the birthdays already reached, extra months are the whole months elapsed since the last birthday, and extra days complete the gap up to the reference date. The total in days is the raw gap converted into whole days, computed in universal time: no daylight saving shift can skew the result.

First date

Start date of the comparison.

Second date

End date of the comparison.

Difference between the two dates

Milestone	Value
Full years	—
Extra months	—
Extra days	—
Total days	—
Weeks	—
Hours	—
Minutes	—

Both dates are required to show the difference.

A duration, not an age

The difference does not look for birthdays reached: it converts the raw gap between the two dates into years, months, days, weeks, hours and minutes. That is the formula behind contract terms, leave and deadlines, where the Age tab answers the question « how old is someone today? ».

Upcoming birthdays

From the date of birth entered in the top bar, the tool rolls out the ten upcoming birthdays with the date, the day of the week and the number of days remaining. A birthday falling on 29 February is celebrated on 28 February in non-leap years.

#	Date	Day	Days remaining

No birthdays calculated yet.

Plan the important dates

Check the day of the week of each birthday: a 29 February falling on a Monday shifts, a party between a weekday and a weekend changes date. The table shows the exact day so you can move a dinner or send a card on time, without relying on memory.

Local activity

Each calculation is stored in your device's local storage. Nothing is sent: if you clear the history, it is lost for good.

Calculations0

Last calculation—

Most common birth year—

Cumulative days0

Calculation history

#	Date	Birth	Reference	Age

No calculations saved yet.

Search the cheat sheet

Filter the rows of the table below: typing « calendar » or « milestone » is enough to isolate the concept you are after.

Calendar, calculations and milestones

Category	Term	Definition
Calendar	Leap year	A 366-day year with a 29 February: 2024, 2028, 2032 and every multiple of four except centuries.
Calendar	Month	Eleven months of 28 to 31 days: twelve months are never the same length, hence the three components of the exact age.
Calendar	Week	Seven consecutive days: the total in days divided by seven gives the weeks elapsed, ignoring the years.
Calendar	Julian day	An unbroken count of days since 1 January 4713 BC: it dates astronomical events without a calendar.
Calendar	Time zone	The offset from Greenwich: this tool computes in universal time so results stay accurate all year round.
Calculation	Exact age	The triplet of years, months and days fully elapsed between the birth and the reference date.
Calculation	Age in full years	The number of full years: the age on official documents and the one you give at dinner parties.
Calculation	Age in days	The raw gap between the two dates converted into whole days, then into weeks and hours.
Calculation	Next birthday	The first occurrence of the birth day and month after the reference date.
Calculation	Days remaining	The gap between today and the next birthday: a countdown that starts again the day after.
Milestone	365 days	The length of a common year, against 366 in a leap year: the running average is 365.2425 days.
Milestone	52 weeks	Three hundred and sixty-five days divided by seven make fifty-two weeks and one day, two in a leap year.
Milestone	18 years	The legal age of adulthood in most countries, and the first birthday often counted.
Milestone	65 years	The standard retirement age in many pension systems.
Milestone	100 years	The centenarian: the age at which birthdays become exceptional and are often celebrated publicly.
Date	YYYY-MM-DD	The international format defined by the ISO 8601 standard, used by HTML date fields and databases.
Date	Reference date	The date at which the age is measured: today when the field is empty, any other day otherwise.
Date	Age on 1 January	An age expressed at a fixed date, handy for comparing annual statistics or censuses.
Status	Adult	A person who has reached the legal age of majority, generally set at eighteen.
Status	Centenarian	A person past one hundred, often tied to an insurance premium or an award.
Shortcut	Ctrl + Enter	Re-runs the calculation for the entered date of birth, from any tab of the tool.
Use	Administrative file	Checking the age shown on an ID card, a contract or a school record before submitting it.

Calculations run in your browser · Ctrl + Enter to calculate · no network requests · 100% local, nothing leaves your device.

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The age calculator is free and unlimited: no account, nothing to install, no network requests. Premium unlocks the whole Volade ecosystem.

FreeExact age in years, months and days, totals in days, weeks and hours

FreeDate difference and ten upcoming birthdays with the day of the week

FreeLocal history, statistics and calendar cheat sheet

PremiumEncrypted cloud sync of your dates across your devices

PremiumAPI access and scripts shared across the ecosystem tools

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Features

Measure an age, a span and the upcoming birthdays

Three calculation modes, ten milestones and a local history — everything you need to date an event without leaving the browser.

Exact age, totals and next birthday

The date of birth and the reference date produce ten milestones in one pass: full years, extra months and days, total in days, weeks and hours, the day of the week of birth, the date of the next birthday, days remaining and leap years crossed. The full age appears above the table, ready to copy.

Calculate my age

Two dates compared in one click

The Difference tab converts the raw gap between two dates into years, months, days, weeks, hours and minutes: the exact length of a contract, a leave or a deadline, with no birthdays in the way. The Birthdays tab, in turn, rolls out the ten upcoming occurrences with their date, day of the week and countdown in days.

Compare two dates

History, statistics and cheat sheet

Each calculation joins the local history with the birth date, the reference date and the resulting age, summarised by four indicators and a chart of the last seven days. The cheat sheet, filterable by keywords, recalls leap years, the ISO 8601 format, the age of majority and duration milestones; everything is erased in one click.

See the history

How it works

Know an exact age in three steps

No installation, no sign-up: the tool is always ready, on mobile as well as desktop.

Enter the date of birth

Open the calendar of the « Date of birth » field and pick the exact day on the birth certificate, or load one of the three examples provided. Nothing is sent: your input stays on your device, even offline.

Choose the reference date

Leave the field empty for today's age, or set a past or future date to measure the age at a precise moment. Click « Calculate » — or Ctrl + Enter — displays the full age and the ten milestones.

Review, copy, archive

Check the extra months and days, copy the age and the milestones to the clipboard, then browse the Birthdays, Difference and Statistics tabs: each visit leaves a line in the local history.

Quick reference

Age milestones at a glance

What most people check before filling in a form — with full definitions in the « Cheat sheet » tab.

Milestone	Value	Typical use
Age in full years	full years elapsed	official documents, civil records
Exact age	years + months + days	contracts, insurance, exams
Total in days	gap converted into whole days	statistics, comparisons
Weeks	days ÷ 7	planning, project tracking
Hours	days × 24	working time, on-call shifts
Next birthday	the following day and month	reminders, cards, celebrations
Days remaining	gap until the next birthday	countdowns
Date difference	raw gap between two dates	contract and leave durations
29 February	28 February outside leap years	rare births
YYYY-MM-DD format	ISO 8601 standard	universal input, export

How do you calculate an exact age?

An exact age breaks down into three components: the number of birthdays already reached, then the whole months elapsed since the last birthday, then the remaining days. The birth day and month are first compared with those of the reference date: if the day has not arrived yet, the current year does not count and we go back one year. The residual gap is then converted into months, allowing for months of different lengths, and finally into days. That is the method the tool follows, computed in universal time so daylight saving never shifts the result.

Two full measures follow. The total in days converts the raw gap between the two dates into whole days, then into weeks and hours — the same value that underpins longevity statistics. The next birthday is the first occurrence of the birth day and month after the reference date, which gives the days left until the celebration.

What is the difference between age in full years and exact age?

The age in full years counts only the full years: a person born on 15 May 1990 is thirty-six in full years on 15 May 2026, and stays so until the next day. The exact age adds the extra months and days: on that same day, they are thirty-six years, four months and twenty-four days old. Official documents use the first, insurance, exams and pension calculations often the second. Both answers are therefore correct — as long as you say which one you give.

Beware of rough conversions: dividing three hundred and sixty-five days by the length of a year produces « average » years that drift several days from reality after a few decades. For a contractual span in days, prefer the Difference tab; to state someone's age, prefer the Age tab.

How do you calculate the difference between two dates?

The difference does not look for birthdays: it measures the raw gap. It is first converted into years and months by direct subtraction — 1 January 2020 to 9 October 2026 gives six years, nine months and eight days — then into whole days from the calendar, and finally into weeks, hours and minutes by multiplication. That is the formula behind contract terms, leave, delivery deadlines and seniority counters.

What the calculator does not do

It does not compute gestational age, life expectancy, conception dates or star signs. It draws no data from your identity: everything starts from the two dates you type. It syncs nothing across your devices, creates no account and sends no network request — the history lives in the browser's local storage and disappears with it.

Recommended for

Parents tracking their children's growth and birthdays, teachers and office staff checking school age or eligibility for a competition, HR and payroll managers verifying seniority or a retirement date, insurers and notaries validating a date of birth on a file, future retirees planning a schedule, and anyone who wants to know their exact age quickly and without leaving a trace, along with the BMI calculator, the character counter, the URL encoder decoder, the regex tester and the hash generator.

FAQ

Frequently asked questions about the age calculator

Everything you want to know before entering a date of birth, comparing two dates or sharing a result.

How do I calculate my exact age in years, months and days?

Enter the date of birth in the top field, leave the reference date empty to aim at today, then click « Calculate ». The tool shows the full age — for example thirty-six years, four months and twenty-four days — then a table of ten milestones: full years, extra months and days, total in days, weeks, hours, day of the week, next birthday, days remaining and leap years crossed.

Why does my age in days differ from another site's calculations?

Because several methods exist. Some divide the number of days by 365.25 and produce « average » years that drift from reality; others count calendar years, and still others ignore the months. Here, the total in days is a raw calendar gap computed in universal time, while the exact age counts the birthdays actually reached: both values are correct, but they do not answer the same question.

What happens if I leave the reference date empty?

The tool uses the current day, midnight in your time zone but converted to universal time for the calculation: that is today's age. To rebuild an age on a precise date — the day of an exam, a signature or a retirement — fill in the field: the table recalculates immediately, without changing the date of birth.

How are 29 February and leap years handled?

A leap year has 366 days: it is a year divisible by four, except for centuries not divisible by four hundred — 2000 was, 1900 was not. For a person born on 29 February, the tool places their birthday on 28 February in non-leap years so that it stays in the same part of the year. The « Leap years crossed » row counts the 29 Februarys actually falling between the birth and the reference date.

What is the difference between age and the difference between two dates?

The Age tab counts the birthdays reached and then adds the remaining months and days: it answers « how old is someone today? ». The Difference tab converts the raw gap between two dates into years, months, days, weeks, hours and minutes: it answers « how much time separates these two dates? ». A contract of six years and nine months is computed in the second, a person's age in the first.

What do you do with my date of birth?

Nothing: the calculation happens in your browser, in JavaScript, with no network request. The dates you enter are neither sent to nor stored on our servers. Only the calculation history is kept, in your device's local storage, and you can clear it in one click from the Statistics tab — it also disappears if you delete the site's data.

Does the tool work offline?

Yes: once the page has loaded, everything runs locally, with no network call. Bookmark it or use it from a device without internet access, the calculation stays available. The examples, the cheat sheet and the history also work offline, since nothing depends on a server.

Can I share the result?

The « Copy result » button puts the full age and every milestone on the clipboard, in plain text, ready to paste into a message, an email or a spreadsheet. The copy never leaves your device: your clipboard receives the content, not our servers.

100% local age calculator: no date ever leaves your browser

Unlike online services that send your date of birth to a server to get a result, everything happens here: the calculation is written in JavaScript, it runs on your device and the result is displayed before anything can leave the page. That is what makes it possible to enter the date of birth of a relative, a student or a client on a public network or offline, knowing that nothing is logged. The history, the statistics and the cheat sheet live in the browser's local storage, and « Clear history » erases them for good.

The licence Volade Premium adds an optional, encrypted cloud sync independent of the tool — the rest stays free and unlimited, with no sign-up.

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