Date and Time Calculators

Choose a date calculator for days, dates, and weeks

Use these pages for calendar dates and date conventions. The right choice depends on the result you need.

• Business Days Calculator counts business days between a start date and an end date with the workweek and holiday list you choose. It shows the formula, assumptions, intermediate values, validation, and a result you can copy or download.
• Date Add Calculator adds or subtracts days, weeks, months, or years from a date. It shows the assumptions and intermediate values, then validates the input before presenting a result you can copy or download.
• Date Difference Calculator compares two dates in days and weeks and gives a calendar breakdown in years, months, and days.
• Week Number Calculator finds the calendar week for a valid date using ISO 8601, US Sunday-start, or simple Monday-start conventions.

Use time calculators for durations, countdowns, and time zones

Choose these pages when the calculation includes a time of day, a target moment, or a named time zone.

• Countdown Calculator calculates the time remaining until, or elapsed since, a target date and time in a selected time zone.
• Time Duration Calculator calculates elapsed time between two date-times, or adds and subtracts a duration measured in days, hours, minutes, and seconds.
• Time Zone Difference Calculator calculates the exact offset difference between two IANA time zones for a chosen date and time. It uses a deterministic browser calculation with no live data.
• Unix Timestamp Calculator converts a Unix timestamp to a date and time in a time zone available in your browser, or converts a date and time into a Unix timestamp.

Work hours calculators for shifts, breaks, and overtime

These tools use the work records and rules you enter. They do not apply a jurisdiction's labor rules automatically, so check the settings and thresholds before using a result for payroll or reporting.

• Date and Work Time Calculator combines business days with custom holidays, date addition and subtraction, elapsed duration across midnight, ISO week numbers, countdowns, and paid work hours with breaks, overtime, and split shifts. You can also choose the locale, weekday schedule, time zone, break policy, and overtime thresholds.
• Timesheet Calculator calculates weekly work hours and overtime from daily start times, end times, and breaks. You set the time zone, break rule, week-start day, and overtime thresholds.
• Work Hours Calculator calculates payable work hours from shift times, unpaid breaks, punch-time rounding, and an overtime threshold. It also has an optional gross-pay estimate.

Typical jobs for date and time calculators

For a working-day count, enter the start date, end date, workweek, and holiday list in Business Days Calculator. For a timestamp conversion, enter the timestamp or date-time in Unix Timestamp Calculator and choose a time zone available in the browser.

To compare locations at a meeting date and time, use Time Zone Difference Calculator with two IANA time zones. For a shift record, enter start and end times, unpaid breaks, rounding, and an overtime threshold in Work Hours Calculator or Timesheet Calculator.

Date and Work Time Calculator keeps calendar work and paid-time calculations together. Choose a narrower page for one result, such as a date difference, a countdown, or a week number.

Where to start if you are unsure

Choose Business Days Calculator for working-day counts, Date Difference Calculator for two-date comparisons, Time Duration Calculator for elapsed time, and Time Zone Difference Calculator for location offsets. Use Work Hours Calculator or Timesheet Calculator for shift records. Choose Date and Work Time Calculator if the same task includes several of these operations.

Frequently asked questions