Altersrechner
Calculates age from a date of birth and a selected reference date.
How this calculator works
The entered dates or periods are evaluated using the displayed units. Enter values in the units shown, check the selected period or mode, and then apply the formula below.
Information you need
date of birth and reference date
Formula used
Age = completed years between date of birth and reference date
Two worked examples
Example 1
Born on 15 May 2000: on 15 May 2026 the person is exactly 26 years old.
Example 2
Born on 20 December 1990: on 14 November 2026 the person is still 35 years old.
When should you use this calculator?
For birthdays, age checks and age-related planning.
Common mistakes to avoid
Subtracting only the years and overlooking whether the birthday has occurred.
Frequently asked questions
1. Which values do I need to enter in the Age calculator?
date of birth and reference date
2. How does the Age calculator calculate the result?
Age = completed years between date of birth and reference date
3. When is the Age calculator most useful?
Calculates age from a date of birth and a selected reference date. For birthdays, age checks and age-related planning.
4. Which input mistakes can affect the Age calculator result?
Subtracting only the years and overlooking whether the birthday has occurred.
5. How accurate and binding is the Age calculator result?
The result is a calculation aid. Check your inputs and the rules that apply to your situation.