Find the exact age gap between two people. Enter both birth dates (and names if you like) to see the difference in years, months and days, who is older, the gap in total days, weeks and months, and both ages today.
Enter your values to see the result.
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How to use the Age Difference Calculator
Enter the first name (optional) and birth date.
Enter the second name and birth date. The order doesn't matter.
Press Calculate difference to see the age gap and who is older.
Check the extra results for the gap in days, weeks and months and both ages today.
Look at the milestones or copy the summary to share it.
How the age gap is calculated
Sort the two birth dates so the earlier one comes first.
Count the whole calendar months from the earlier date without passing the later date, and split them into years and months.
Count the remaining days.
Separately, count the exact number of days between the two dates for the totals in days, weeks and decimal years (days ÷ 365.2425).
Example: May 14, 1990 to November 2, 1994. Whole months: 53 (4 years 5 months), reaching October 14, 1994. Remaining days: 19. Age difference: 4 years, 5 months, 19 days, which is 1,633 days.
Same gap, changing ratio
Younger person's age
Older person (5-year gap)
Age ratio
5
10
2.00 : 1
10
15
1.50 : 1
20
25
1.25 : 1
30
35
1.17 : 1
50
55
1.10 : 1
75
80
1.07 : 1
The gap in years never changes, but it matters less and less as both people get older.
Frequently asked questions
How do you calculate the age difference between two people?
Count from the earlier birth date to the later one: first the whole years, then the whole months, then the remaining days. For example, from May 14, 1990 to November 2, 1994 is 4 years, 5 months and 19 days.
Does the age difference ever change?
No. The gap between two birth dates is fixed. What changes is the ratio between your ages: a 4-year gap is huge between a 2 and a 6 year old but small between people aged 60 and 64.
How are leap years and month ends handled?
The calculator counts real calendar months. If the starting day doesn't exist in a month, such as the 31st in a 30-day month, it uses the last day of that month, and February 29 birthdays are handled the same way. Total days are counted exactly, including leap days.
When was the older person twice as old as the younger?
That happens exactly when the younger person's age equals the age gap, which is the date the younger person has lived as long as the gap. For a gap of 4 years, 5 months and 19 days, it is when the younger person reaches that age.
What is the 'half your age plus seven' rule?
It is a popular informal rule for dating age gaps: the youngest partner considered socially acceptable is half your age plus 7 years. It is a cultural rule of thumb, not a scientific or legal standard.
Is my data saved anywhere?
No. The calculation runs in your browser. Your last entries are kept only in your own browser's storage so the form is filled in next time.