Age Gap Calculator
Find the exact age gap between two people in seconds. Enter two birth dates and our calculator returns the difference in years, months, weeks, days, hours, minutes and seconds. We also tell you which person is older, the percentage difference, and whether the gap passes the popular half-your-age-plus-seven dating rule. Useful for couples, siblings, parents and children, twins born minutes apart, friends comparing ages, and writers building character backstories.
Calculate your exact age in years, months, and days.
Whether you're planning a milestone birthday celebration, settling a debate with a sibling about who's older, calculating the spread between you and your partner, comparing twins or family members, or just curious about a celebrity couple's age difference — this calculator gives you a precise answer with no ads or signups. The result handles leap years correctly and works for any two dates from 1900 to 2100.
How the age gap is calculated
The calculator subtracts the older birth date from the younger birth date and breaks the result down into time units:
- Years and months: standard date subtraction with month borrowing
- Days: total days between the two dates
- Hours, minutes, seconds: precise duration including leap days
The half-your-age-plus-seven rule
A common social heuristic for dating compatibility says the youngest socially acceptable partner age equals (your age ÷ 2) + 7. Our calculator automatically checks both directions:
- If you're 30, your minimum partner age is 22
- If you're 40, your minimum partner age is 27
- If you're 50, your minimum partner age is 32
The rule isn't legal advice — it's a cultural rule of thumb popularised in advice columns since the 1900s.
Common reasons people calculate age gaps
- Couples checking compatibility ranges
- Siblings with close birthdates determining who's older
- Twins born across midnight or across time zones
- Parents tracking the age spread between children
- Writers and screenwriters defining character ages
- Genealogy research into family generations
- Sports leagues with strict age cutoffs
- School registration and grade placement
How it works
- 1Enter the first person's date of birth using the date picker.
- 2Enter the second person's date of birth on the second field.
- 3Click Calculate to see the age gap in years, months, days and the half-plus-seven rule check.
- 4Copy the result or share the URL — both birth dates are included for easy re-use.