How We Calculate

We aim to make every calculation understandable by explaining the rules and assumptions behind our results.

Calendar date calculations

Date differences are calculated using calendar dates rather than elapsed local clock hours. This avoids daylight-saving transitions changing the number of calendar days.

Inclusive and exclusive day counts

A standard date difference measures the elapsed calendar days between two dates. An inclusive count adds one to include both the starting and ending dates.

Business days

The business-day calculator treats Monday through Friday as weekdays and Saturday and Sunday as weekends. Holidays are excluded only when the user enters them.

Weeks

The total number of calendar days is divided by seven to calculate full weeks and remaining days.

Months

Calendar months have different lengths. Our months calculator counts complete calendar months and then calculates the remaining days rather than assuming every month has 30 days.

Age

Age is calculated by comparing the birth date with a reference date, taking completed years, months, and days into account.

Time duration

Time duration is calculated in minutes from a 24-hour clock. An overnight option allows the end time to fall on the following day.

Seasonal countdowns

The current season countdowns use approximate fixed calendar dates. They do not calculate exact astronomical equinox or solstice times.

Event countdowns

Halloween, Thanksgiving, and Western Gregorian Easter use their respective calendar rules. Thanksgiving supports the United States and Canada as separate date conventions.