Age Calculators

AgeLab guides

Plain-language answers to age calculators questions, written from the same sourced data behind AgeLab. Every guide lists its sources and the date it was last updated.

Updated June 10, 2026
How is your age actually calculated — and when does it change?
How the completed-years convention works, what happens to Feb 29 birthdays, how East Asian age reckoning compares, and why law uses calendar-day precision.

AgeLab guides

How is your age actually calculated — and when does it change?