About DaysTo

DaysTo is a small collection of date calculators built around one idea: date math should be accurate, instant and completely private. Every tool runs in your browser with plain JavaScript. Nothing you enter, whether a birth date, an event date or a range, is ever sent to a server, stored or tracked.

How the calculations work

Ages and date differences

Ages and gaps between dates are measured in whole calendar days. The tools strip the time of day and count the midnights between two dates, which keeps results stable regardless of the hour and immune to daylight saving shifts. The years, months and days breakdown uses natural borrowing, counting whole years first, then whole months, then leftover days, exactly the way people state a duration out loud.

Leap years

A leap year adds February 29 to keep the calendar aligned with the solar year of roughly 365.2422 days. Years divisible by four are leap years, except century years, which must also be divisible by 400. That is why 2000 was a leap year and 1900 was not. Because every calculation counts real calendar days, leap days inside a range are always included automatically.

Week numbers

The week number tool follows ISO 8601, the international standard used by most software and businesses. Weeks start on Monday, and week 1 is the week containing the year's first Thursday, which is also the week containing January 4. Most years have 52 weeks and some have 53.

Business days

The business-day count includes Monday through Friday and skips weekends. Public holidays are left in, because holiday calendars differ by country and region, so the figure represents the working-week baseline that you can adjust for any local holidays.

Holiday countdowns

Fixed holidays such as Christmas are simple lookups. Moving holidays are resolved by rule: Thanksgiving is the fourth Thursday of November, Memorial Day is the last Monday of May, and so on. Easter and the dates tied to it use the standard Gregorian computus, the same algorithm used to publish Easter dates decades in advance. Lunar festivals such as Diwali and Chinese New Year use the officially published dates for the years ahead.

Privacy

There are no accounts, no cookies for tracking, and no analytics that follow you. The site is static and the math happens on your device. You can use every tool offline once the page has loaded.

Ready to count? Start with the age calculator or the date calculator.