Age Calculator
Calculate age in years, months, weeks and days from a date of birth to any reference date. Useful for legal forms, applications and milestone planning.
Last updated: May 2026
How it works
Enter a date of birth and a reference date to calculate the exact age in years and days. The calculator handles leap years correctly, so it gives the right result even for people born on February 29. Use it to verify age requirements, plan retirement eligibility, or see exactly how old someone will be on a future date.
Common age milestones
| Age | Common significance |
|---|---|
| 16 | Driving licence eligibility (many countries) |
| 18 | Legal adult (EU, UK, most countries) |
| 21 | Legal adult for alcohol (US); some insurance thresholds |
| 25 | Full car hire rates; brain development milestone |
| 65-67 | Standard retirement age (varies by country) |
Exact age for eligibility and planning
Many eligibility rules hinge on exact age at a specific date, not just the birth year. Scholarship deadlines often require applicants to be under 25 on the closing date. Youth sports competitions enforce age cutoffs as of January 1 of the competition year. Insurance premiums change at exact birthday milestones: car insurance drops at 25 in most markets, and some health plans adjust at 30, 40, and 50. Using an estimated age rather than the exact figure can mean the difference between qualifying and being turned away or overpaying for months before the correct rate takes effect.
Retirement planning benefits from the same precision. State pension ages in many countries are not a round birthday but a specific qualifying date based on birth date and the prevailing pension rules, which have changed multiple times in recent decades. Knowing that you reach pension age on a particular Tuesday in October is more useful than knowing you will be 67 next year, especially when aligning it with a contract end date or a property sale. The reference date field in this calculator lets you pin the calculation to any future date rather than today, which is useful for these forward-looking checks.
Frequently Asked Questions
How accurate is the age calculation?
The calculator uses exact calendar dates to compute the difference in years and remaining days. It accounts for leap years and varying month lengths.
Can I use a future date as the reference date?
Yes. Enter any date as the reference date, including future dates, to see how old someone will be at that point.
How does the calculator handle leap years?
Leap years have 366 days instead of 365, with February 29th appearing every 4 years (with exceptions for century years). If someone is born on February 29 in a leap year, the calculator treats their "birthday" as February 28 or March 1 in non-leap years, depending on the convention. The age in years remains accurate, but the exact day count accounts for the leap day correctly.
What's the difference between age at last birthday and exact age in years and days?
Age at last birthday is the common way people state their age (someone is "25" if they've already passed their 25th birthday this year). Exact age in years and days is more precise, you might be 25 years and 47 days old, not just "25." This precision matters for medical records, eligibility thresholds (like minimum age requirements), and calculating retirement dates or milestones.
Can I calculate someone's age in different cultures that use different calendar systems?
This calculator uses the Gregorian calendar (the international standard). Some cultures use different calendar systems, the Islamic calendar, Hebrew calendar, or traditional East Asian lunar calendars, where age is calculated differently. If you need age in a different calendar system, convert the dates to Gregorian first, then use this calculator.