en-US · browser-local
Date, duration, and calendar calculations without the SaaS.
DateToolMage is a browser-first date, duration, calendar and time-related calculation workbench.
Dates stay civil calendar dates. Weekend-only business days say so. Holidays, timezones, and accounts stay out of this foundation.
Certified tools
Days Between Dates
Count calendar days between two dates with inclusive or exclusive rules.
/days-between-dates
Add or Subtract Dates
Add or subtract years, months, weeks, and days from a calendar date.
/add-subtract-dates
Business Days Calculator
Count or add Monday–Friday business days. Weekends only; holidays are not excluded.
/business-days
Age Calculator
Calculate completed years, months, and days from a birth date.
/age-calculator
Day of Week Calculator
Find the weekday for any valid calendar date.
/day-of-week
Week Number Calculator
ISO-8601 week number and year for a calendar date.
/week-number
Date Countdown
Count calendar days until or since a target date.
/date-countdown
Date Duration Calculator
Break a date span into years, months, weeks, and days.
/date-duration