Idiot Date Tools is a single-category toolbox built entirely around dates and calendars — age, duration, timezones, deadlines, holidays and more. Every tool runs instantly in your browser. No signup, no ads blocking the calculator, no data leaving your device.
1 tool in this category
4 tools in this category
Find the exact number of days, months and years between any two dates.
Open tool →Work out an exact age in years, months and days from a birth date.
Open tool →Add or subtract days, weeks, months or years from any starting date.
Open tool →Find the precise age gap between any two people, in years and months.
Open tool →1 tool in this category
5 tools in this category
Instantly find which weekday any calendar date fell or falls on.
Open tool →Check instantly whether any year is a leap year, and why.
Open tool →Find the ISO-8601 week number for any date of the year.
Open tool →Find the Western zodiac sign and date range for any birth date.
Open tool →Find the exact date of the 1st, 2nd, 3rd, 4th or last weekday of any month.
Open tool →5 tools in this category
Live countdown to any future date, minute, hour or event.
Open tool →Generate and print a clean monthly or full-year calendar for any year.
Open tool →Generate the next occurrence and countdown for any recurring birthday or anniversary.
Open tool →Calculate your exact retirement date from your birth date and target age.
Open tool →See exactly what percentage of any year has elapsed and how many days remain.
Open tool →4 tools in this category
Convert dates between the Gregorian and Hijri (Islamic lunar) calendars.
Open tool →Browse public and bank holidays for major regions across any year.
Open tool →Find the moon phase for any date, past or future, plus how many days until the next full and new moon.
Open tool →Find the Chinese zodiac animal and element for any birth year.
Open tool →2 tools in this category