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Age Calculator - Calculate Your Exact Age in Years, Months & Days

Free online age calculator. Find your exact age in years, months, days, weeks, and hours. Calculate age between any two dates. Birthday countdown included.

9 min read

iAbout This Calculator

The age calculator is an essential tool for determining exact age down to the day. Whether you need to know your precise age for official documents, calculate someone's age at a specific historical date, or simply satisfy your curiosity about how many days you've been alive, our calculator provides comprehensive results instantly. Enter any birth date and target date to calculate the exact duration between them in years, months, days, weeks, and even hours. The calculator also includes a birthday countdown feature showing how many days remain until the next birthday. Perfect for legal requirements, milestone celebrations, or historical research.

?How to Use

  1. 1

    Enter your date of birth using the date picker or by typing in the format shown. You can select dates going back over 100 years.

  2. 2

    Optionally, change the 'Calculate Age As Of' date. By default, this is set to today's date, but you can choose any date to calculate age at that point in time.

  3. 3

    Click Calculate to see your results. The calculator will process instantly.

  4. 4

    Review your complete age breakdown: years, months, and days in the primary display, plus total days, weeks, and months in additional statistics.

  5. 5

    Check the birthday countdown section to see how many days until your next birthday and what day of the week it falls on.

fFormula

\text{Age} = \text{End Date} - \text{Birth Date}

Age is calculated by subtracting the birth date from the target date. The calculation accounts for varying month lengths, leap years, and proper day counts. Years are completed only when the anniversary month and day have passed.

Birth Date
The starting date (date of birth)
End Date
The date to calculate age as of (default: today)
Age
The precise duration between the two dates

Examples

Calculate Current Age

Inputs: birthDate: 1990-06-15, toDate: 2026-01-05
35 years, 6 months, 21 days

From June 15, 1990 to January 5, 2026: 35 complete years, 6 additional months, and 21 extra days.

Age in Total Days

Inputs: birthDate: 2000-01-01, toDate: 2026-01-05
9,501 days

26 years plus 5 days, accounting for 6 leap years (2000, 2004, 2008, 2012, 2016, 2020, 2024) = 9,501 total days.

Historical Age Calculation

Inputs: birthDate: 1879-03-14, toDate: 1955-04-18
76 years, 1 month, 4 days

Albert Einstein's age at time of death: born March 14, 1879, passed April 18, 1955.

Next Birthday Countdown

Inputs: birthDate: 1995-08-20, toDate: 2026-01-05
227 days until birthday

Next birthday: August 20, 2026. Days remaining from January 5: 227 days (Thursday).

Use Cases

Legal and Official Documents

Many legal processes require exact age verification. Calculate precise age for passport applications, retirement eligibility, voting registration, or contract validity that depends on age requirements.

Milestone Celebrations

Plan for significant birthdays and anniversaries. Know exactly when someone turns 10,000 days old, reaches their golden birthday, or hits other unique milestones worth celebrating.

Healthcare and Medical Records

Medical professionals often need precise age calculations for proper dosing, developmental assessments, and age-appropriate screenings. Calculate patient ages accurately for medical contexts.

Historical Research

Calculate the ages of historical figures at significant events, determine how old someone was during specific time periods, or verify biographical data in research projects.

Astrology and Numerology

Those interested in astrology or numerology often need precise age and day counts. Calculate exact days lived, life path numbers, or ages at specific planetary alignments.

Frequently Asked Questions

How is age calculated exactly?
Age is calculated by counting complete years from birth date to target date, then adding remaining months and days. A year is complete only when both the month and day of your birth anniversary have passed. Leap years and varying month lengths are automatically handled.
Why does my age in months seem off?
Months have varying lengths (28-31 days), which can affect calculations. The calculator uses actual calendar months rather than a fixed 30-day average. Your age in months counts complete calendar months from your birthday date each month.
How accurate is the total days calculation?
The total days calculation is precise, accounting for all leap years between your birth date and the target date. Leap years occur every 4 years, except for century years not divisible by 400. The calculator handles all these rules automatically.
Can I calculate age between any two dates?
Yes! While the calculator defaults to today's date, you can change the 'Calculate Age As Of' field to any date. This allows you to find someone's age at a historical event or future date.
What timezone does the calculator use?
The calculator uses date-only calculations without time components, so timezones don't affect the results. Your age is calculated based on calendar dates, not precise time elapsed.
How do I calculate the age difference between two people?
Calculate each person's age in total days, then subtract to find the difference. Alternatively, use one person's birth date as the birth date and the other's birth date as the target date to see the exact age gap.
Why is my birthday countdown different from other calculators?
Some calculators count the birthday itself in the countdown (inclusive) while others don't (exclusive). Our calculator counts the days remaining UNTIL your birthday, not including the birthday itself.
Can I use this for calculating pet ages?
Yes! Enter your pet's birth date to calculate their exact age. For 'dog years' or 'cat years' conversions, you'll need to apply the appropriate multiplier to the result (roughly 7 human years per dog year, though this varies by breed).

Conclusion

Knowing your exact age has never been easier. Our age calculator provides precise results in multiple formats, from traditional years-months-days to total days lived. Whether for legal documents, personal curiosity, or planning celebrations, this tool delivers accurate age calculations instantly. Bookmark this page for quick access whenever you need age-related calculations, and explore our other date and time tools for more temporal utilities.