Choose a calculator
To measure time between dates, use the days between dates calculator, which gives days, weeks, months and weekdays, or the age calculator for exact years, months and days. To find a date, the date calculator adds or subtracts days, weeks, months and years, and the days until calculator counts down to holidays and your own dates.
For work and planning, the business days calculator skips weekends and optionally US federal holidays, and the week number calculator gives ISO week numbers and week dates.
For hours and time, the hours calculator finds the time between a start and end, the time card calculator totals a week, the time calculator adds and subtracts durations, and the time to decimal calculator converts hours and minutes to decimal hours.
- Age Calculator – Exact age in years, months, days and hours, with next birthday.
- Days Between Dates Calculator – Days, weeks, months and weekdays between two dates.
- Date Calculator – Add or Subtract Days, Weeks, Months, Years – Add or subtract days, weeks, months and years from a date.
- Days Until Calculator – Countdown to Any Date – Countdown in days, weeks and weekdays to holidays or any date.
- Business Days Calculator – Working Days Between Dates – Working days between dates, or add working days, skipping weekends and holidays.
- Week Number Calculator – What Week Is It? – ISO and US week number, weekday, day of the year and quarter for any date.
- Time Calculator – Add or Subtract Hours, Minutes & Seconds – Add or subtract durations in days, hours, minutes and seconds.
- Hours Calculator – Hours Between Two Times – Hours and minutes between two times, with a break and overnight shifts.
- Time Card Calculator – Weekly Hours – Weekly timesheet total from daily in and out times, with breaks.
- Time to Decimal Calculator – Hours and Minutes to Decimal Hours – Hours and minutes to decimal hours and back, with a minutes chart.
Frequently asked questions
Which calendar do the date calculators use?
The Gregorian calendar, which is the standard civil calendar in most of the world. A year is a leap year if it divides by 4, except for centuries, which must divide by 400. Dates before the Gregorian calendar was adopted are calculated as if it had always been in use.
What does "today" mean in the calculators?
Today is the date on your device. Some calculators, such as age and days until, use it as the default, and you can change it by entering your own dates.
Are months counted as 30 days?
No. Months are counted as calendar months, so 31 January plus 1 month is the last day of February. Where a total number of days is needed, the calculators also show days exactly.
Do the business day calculations include public holidays?
Only US federal holidays can be selected, observed on the Friday or Monday when they fall on a weekend. Other countries' holidays and company closures are not included, so subtract those separately.
Are the hours calculators suitable for payroll?
They add up time accurately, but they do not apply pay rules, overtime law or rounding policies, which vary by place and employer. Treat them as a way to check a timesheet total.
Why do ISO week numbers differ from other week numbers?
ISO weeks start on Monday, and week 1 contains the first Thursday of the year, so early January can belong to the previous year's last week. The US system starts on Sunday and counts the week containing 1 January as week 1. The week number calculator shows both.