AgeCalc blog
Plain-English posts on working with ages — the questions people actually ask, answered with worked examples. Every post pairs with the free AgeCalc calculator, which does the arithmetic in your browser.
School Admission Age: How Age Cutoff Dates Work
What a cutoff date means, how to calculate a child's age on it, a worked example, and why a birthday two days past the line can mean a whole school year of difference.
Leap Year Birthdays: How Age Works If You Were Born on 29 February
When leap-day babies turn a year older in non-leap years, why 28 February and 1 March both get used, and how exact age is counted regardless.
Age Difference Between Two People: How to Calculate It Exactly
The exact age gap in years, months and days, a worked example, and why the gap in whole years seems to change during the year when it does not.
How Old Will I Be in 2030? Your Age on Any Future Date
The simple method for any future year, worked examples, and the birthday-timing trap that makes the quick answer wrong for part of the year.
Age Milestones Worth Celebrating: 10,000 Days, Half-Birthdays & More
Beyond birthdays: your 10,000th day, 1,000 weeks, half-birthdays and round-number birthdays — and how to find the date of each one.