Everyday Calculators & Converters
Age Difference Calculator
Calculate the exact age difference between two people using their dates of birth, in years, months and days. Compare a couple, siblings, friends, a parent and child, or any two people.
- Runs in your browser
- Made for two
Tell us your birthdays
The age difference
Your gap pops up here
Add both birthdays, then hit Calculate. Names are optional.
Age difference
You changed something. Hit Calculate to refresh.
How to calculate the age difference between two people
The age difference is the time between two dates of birth. Enter both birthdays in any order: the calculator finds the earlier one, which belongs to the older person, and counts forward to the later one in whole years, then whole months, then the days left over.
You also see total months and total days, how old each person is today, and a plain sentence such as “Sarah is 2 years, 4 months and 12 days older than Ahmed.” Names are optional; without them the result says Person 1 and Person 2.
Age gap calculator for couples
Choose “Couple / partners” and the Age Difference Calculator becomes a love age gap calculator: your two names sit side by side with a heart between them, the result is headed “Your age gap”, and you see how many months apart you are. Share the link with your partner if you like.
It tells you the exact couple age difference and who is older. It doesn’t rate the gap or say whether it is “ideal”: that’s for the two of you.
Age difference for siblings, friends and family
The calculator isn’t only for romantic relationships. Compare a brother and sister for the exact sibling age difference, two friends settling who is older, colleagues, cousins or grandparents. Choose the relationship, or leave it as “Not specified” for neutral wording.
For a parent and child, the age difference is also the parent’s exact age on the day the child was born. To see one person’s exact age instead, use the Age Calculator.
How the age difference is calculated
Birthdays are read as calendar days, so time zones and clock changes can’t move them by a day.
- Who is older
- The earlier birthday belongs to the older person. The gap runs from the earlier birthday to the later one, so it’s the same whichever person you enter first.
- Years, months, days
- Subtract the years, months and days separately. If the days come out negative, take one month off and add the days of the month before the later birthday’s month; if the months come out negative, take one year off and add 12.
- A worked example
- 31 January 2000 and 15 January 2005: days 15 − 31 = −16, so take a month off and add December’s 31 days (15 days). Months 1 − 1 − 1 = −1, so take a year off and add 12 (11 months). Gap: 4 years, 11 months, 15 days.
- Each person’s age
- Worked out the same way, from each birthday to today’s date on your device.
- The relationship
- Optional. It changes the wording only; the calculation is exactly the same for every choice.
- Totals
- Total months = years × 12 + months. Total days are the calendar days between the two birthdays.
Questions
What is the age difference between two people?
The time between their two dates of birth: whole years, then whole months, then the days left over. The person with the earlier birthday is the older one, and the difference is the same whichever person you enter first.
Is age difference the same as age gap?
Yes. “Age difference” and “age gap” mean the same thing: how much older one person is than the other. This calculator shows it in years, months and days, plus total months and total days.
Can I use this as a love age gap calculator for couples?
Yes. Choose “Couple / partners”, add your names if you like, and the result shows your age gap with both of you side by side. It measures the gap exactly; it doesn’t judge it or apply rules of thumb such as “half your age plus seven”.
Can I calculate the age difference between siblings?
Yes. Enter both birthdays and choose “Siblings” if you like. You get the exact gap between them in years, months and days, which also tells you how old the older one was when the younger one was born.
Can I calculate the age difference between a parent and child?
Yes. Choose “Parent and child” and enter both birthdays. The age difference is also the parent’s exact age on the day the child was born.
How accurate is an age difference calculator?
This one is calendar-exact to the day: it uses the real length of every month and counts leap days, and it reads birthdays as calendar dates so time zones can’t shift them. It doesn’t use times of birth, so it doesn’t count hours.
Does the calculator account for leap years?
Yes. Total days count every calendar day between the two birthdays, 29 February included, and a 29 February birthday is treated as the real date it is.
Is anything sent or saved?
No. The difference is worked out in your browser and nothing is stored. A share link holds the two dates and the relationship you chose. Names are never put in the link or the page address.