About Age Calculator

Calculate exact age in years, months, and days from a birthdate. Part of the DevTools Surf developer suite. Browse more tools in the Date / Time collection.

Use Cases

• Testing age verification logic for registration forms
• Calculating user ages for COPPA or GDPR compliance checks
• Verifying eligibility dates for age-restricted features
• Computing exact ages for HR and payroll systems

Tips

• Enter a birthdate to see exact age in years, months, and days
• Accounts for leap years in the calculation automatically
• Use this to verify age-related validation logic in your apps

Fun Facts

• People born on February 29 (leap day) technically have a birthday only once every 4 years; as of 2024, roughly 5 million people share this birthday.
• The oldest verified person ever was Jeanne Calment of France, who lived 122 years and 164 days (1875-1997).
• In South Korea's traditional age system, babies were considered 1 year old at birth; the country officially switched to international age counting in June 2023.

FAQ

How precise is the age?

Years, months, and days. Leap years and month lengths (28-31) are correctly accounted for. Down to the exact day difference.

Can I use a future date?

Yes — for 'how long until someone's birthday' questions. Or 'in 6 months, I'll be exactly X years Y months old'.

What about different starting dates?

Toggle — 'as of today' or 'as of a specific date'. Useful for historical calculations: 'how old was Einstein when he wrote his 1905 papers?'

Is age computed in gravitational reference?

Ha! No — just Earth calendar days. For special relativity adjustments (the orbiting-astronaut problem), the effect is <1 second per year for ISS astronauts. Not worth computing.