Date & Time

A spin wheel is one of the simplest ways to make an unbiased choice between multiple options. Learn how spin wheels ensure fairness and when to use one over a coin flip.

Why "current year minus birth year" gives the wrong age, the correct calendar-aware algorithm, and how leap years and February 29th birthdays are handled.

Calculating working days between two dates means excluding weekends and public holidays from the total. Learn the formula, a worked example, and when this matters most.

Finding the exact age gap between two people involves more than subtracting birth years. Learn the correct method to calculate age difference in years, months, and days.

Counting down to your next birthday involves more than a simple date subtraction, especially near year-end or leap years. Here is exactly how the math works.

Calculating your exact age to the day sounds simple — but leap years, months of different lengths, and timezone differences make it surprisingly tricky to do manually. This guide explains the algorithm and the surprising moments when precise age calculation really matters.