Date calculators
for life & work.
Calculate time, compare dates and ages, or plan work, sleep and outdoor activities.
Calculate datesAll date calculatorsJust need to count or move a date?
The general calculator counts calendar days and adds or subtracts days, with inclusive counting and a countdown handoff.
Featured date calculators
Browse all 152 calculatorsTime formats & conversions
All 4 calculatorsTime Calculator
Add or subtract durations, multiply or divide time, calculate overnight differences and move clock times forward or backward. Inspect the working, then copy, print or export.
Open calculatorMilitary Time Converter & Printable Chart
Convert military, 24-hour and AM/PM clock times. Print an hourly or half-hour chart, convert a list and export the results.
Open calculatorTime Duration Converter
Convert seconds, minutes, hours, days and weeks to decimal units or H:MM:SS. Keep long durations intact and convert a whole list.
Open calculatorSun, Moon & outdoors
All 11 calculatorsSunrise & Sunset Planner
Find local sunrise, sunset, dawn, dusk and daylight for a city and date. Compare a month, print a sun calendar or download its events.
Open calculatorMoon Phase Calendar & Full Moon Finder
See the Moon phase and illumination for today or any date, find the next full or new moon, and print or export a monthly calendar.
Open calculatorMoonrise & Moonset Planner
Find local moonrise, moonset and time above the horizon. Browse a month of Moon times, phases and illumination, then print or export.
Open calculatorWorkdays & planning
All 15 calculatorsWork Hours Calculator
Calculate work hours between dates and times, subtract unpaid breaks and compare wall-clock or actual elapsed hours across daylight-saving changes.
Open calculatorTime Card Calculator
Add dated clock-in and clock-out intervals, overnight shifts and unpaid breaks. See daily and weekly hours, custom overtime totals, and export your time card.
Open calculatorBusiness Days Calculator
Count working days between dates with your own workweek and excluded holidays. Choose whether to include each endpoint and see a clear count breakdown.
Open calculatorAges & date spans
All 5 calculatorsAge Difference Calculator
Compare two birth dates in years, months, days and exact total days, and see both people's ages on the same date.
Open calculatorDate of Birth Calculator
Find possible birth dates from an age recorded on a known date. Use completed years or a precise years, months and days breakdown.
Open calculatorAge Calculator
Calculate calendar age on a past, present or future date. See years, months, days, total weeks and the next birthday, with an explicit February 29 convention.
Open calculatorEveryday date math
All 3 calculatorsGeneral Date Calculator
Count calendar days between two dates or add and subtract days. Choose inclusive counting, reverse a range, and copy the result.
Open calculatorDate Range Overlap Calculator
Compare multiple date ranges. Find shared days, overlap across all ranges, unique coverage and uncovered gaps, with explicit inclusive or exclusive end dates.
Open calculatorRecurring Date Generator
Generate daily, weekly, monthly or yearly dates. Choose weekdays, nth-weekday patterns and exclusions, then export a CSV or an all-day recurring calendar.
Open calculatorHome & hobbies
All 8 calculatorsSleep Schedule Calculator
Plan a bedtime or wake-up time from your chosen sleep duration and time-to-fall-asleep estimate, including daylight-saving changes.
Open calculatorReading Finish Date Calculator
Find when you will finish a book or the daily pages needed for a deadline. Choose reading weekdays, skip dates and export a page-by-page schedule to your calendar.
Open calculatorPet Food Reorder Calculator
Estimate when pet food will run short and when to reorder. Combine multiple pets' daily consumption with stock, delivery lead time and a safety buffer.
Open calculatorPay & leave
All 8 calculatorsPTO Accrual Calculator
Project paid time off from your opening balance, accrual schedule, optional cap and planned leave. See the dated ledger and when a target balance is first reached.
Open calculatorVacation Days Needed Calculator
Find the leave needed for a trip with partial departure and return days. Exclude work holidays and lunch, then apply hourly, half-day or full-day charging.
Open calculatorPayday & Payroll Calendar
Generate weekly, biweekly, semimonthly or monthly paydays. Set period lag, processing cutoffs and holiday adjustments, then download your payroll calendar.
Open calculatorCalendar lookups
All 5 calculatorsFiscal Calendar Calculator
Find a date's fiscal year, quarter and month with a custom year-start month. Compare start-year and end-year labels and inspect every monthly boundary.
Open calculatorISO Week Number Calculator
Find the ISO week number, week-year and Monday–Sunday range for a date, or convert an ISO week and weekday back to a calendar date.
Open calculatorDay of Year Calculator
Convert a date to its day-of-year number or a year and day number back to a date. See YYYY-DDD, leap-year length, days remaining and a month reference table.
Open calculatorThe counting rule is part of the answer.
Thirty calendar days, one calendar month and twenty working days can land on different dates. Choose the question you want to answer, then keep its rules alongside the result.
Which calculator should I use?
Use the general calculator for calendar-day differences and simple date shifts. Business-day tools apply your workweek and exclusions. Age and duration tools measure calendar months. ISO week and day-of-year lookups identify a date rather than measure a span.
Are holidays and daylight saving automatic?
Date-only tools count calendar dates, so a daylight-saving change does not add or remove a date. Work Hours and Time Card also offer elapsed-time mode, which applies the selected time zone and asks you to resolve repeated times. Business-day tools can load country and region holidays. Review the holiday selections and add your own closures.
Can I save or share a result?
Calculators offer copy, CSV and print actions; supported date tools also provide setup links. Tools that produce schedules also offer calendar files. Saving inputs is optional. Shared links include the dates and choices you entered, so review birth dates and other personal details before sharing.