Date and Time Calculators

DateTimeCalcs has free calculators for time durations, day counts and holiday countdowns, and each one updates its answer as you type. Results use the time zone on your device, and nothing you enter leaves your browser.

Open the Time Duration Calculator See all calculators

Time Duration CalculatorHours and minutes between two times or dates, with breaks, overnight shifts and decimal hours.

Calculators

Time Duration Calculator
Hours and minutes between two times or dates, with breaks, overnight shifts and decimal hours.
Days Left in the Year
Days, weeks and business days left in the year from today, with a progress bar and a whole-year calendar.
Hours Until Midnight
A live countdown to midnight, or to any clock time, in hours, minutes and seconds.
Time Addition Calculator
Add or subtract hours, minutes and seconds, or find the time X hours from a start time.
Days Until a Date
Count the days, weeks, months and business days from today to any date.
Birthday Countdown
Live countdown to your next birthday, with the weekday it falls on and the age you will turn.
Day of the Year Calculator
Today's day of the year, full days passed, the share of the year gone and the ISO week number.
Days Since Calculator
Count the days, weeks, years, months and business days since any past date.
Average Time Calculator
The average, total, fastest and slowest of a list of mm:ss or h:mm:ss times.
Hours From Now Calculator
The exact time and date any number of hours or minutes from now, live in your time zone.
Hours Ago Calculator
The exact time and date any number of hours or minutes ago, live in your time zone.
Hours Calculator
Weekly time card: daily and total hours worked, overtime past 40 and gross pay, with breaks, overnight shifts and rounding.
Daylight Saving Time
When daylight saving time ends and starts, with a live countdown to the next clock change in your time zone.
Days From Today Calculator
The date any number of days, weeks, months or business days from today, or before it.
Days Between Dates Calculator
Count the days, weeks, months, years and business days between any two dates.

Holiday countdowns

All countdowns

Thanksgiving countdown
Live countdown to Thanksgiving 2026, with weekends and business days left and the next five dates.
Christmas countdown
Live countdown to Christmas 2026, with sleeps left, days to Christmas Eve, weekends and business days.
New Year's Day countdown
Live countdown to midnight on January 1, 2027, in days, hours, minutes and seconds.
Halloween countdown
Live Halloween countdown to October 31, 2026, with weeks and weekends to go and the weekday for the next five years.
Valentine's Day countdown
Live countdown to Valentine's Day 2027, with weeks to go and the weekday it falls on.
Easter countdown
Live countdown to Easter Sunday 2027, with Ash Wednesday, Good Friday and the Orthodox Easter date.
Spring countdown
Live countdown to the first day of spring 2027, with the exact March equinox time in your time zone.
Summer countdown
Live countdown to the first day of summer 2027, with the June solstice time and the length of summer.
Fall countdown
Live countdown to the first day of fall 2027, with the exact September equinox time in your zone.
Winter countdown
Live countdown to the first day of winter 2026, with the December solstice time in your zone.
Black Friday countdown
Live countdown to Black Friday 2026, the day after Thanksgiving, with the Cyber Monday date.
Mother's Day countdown
Days and weekends left until Mother's Day 2027, the second Sunday in May, plus its date for the next five years.
Father's Day countdown
Live Father's Day 2027 countdown, with the years Juneteenth's day off turns it into a three-day weekend.
Memorial Day countdown
Countdown to Memorial Day 2027, the last Monday in May, with its three-day weekend and business days left.
Labor Day countdown
Labor Day 2027 countdown with the three-day weekend, business days left and the 1894 law behind the date.
4th of July countdown
Live countdown to the 4th of July 2027, with hours to go and the federal day off when July 4 hits a weekend.
Juneteenth countdown
Countdown to Juneteenth 2027, June 19, with the federal day off in years it falls on a Saturday or Sunday.
St. Patrick's Day countdown
Live countdown to March 17, 2027, with weekends to go and the weekday St. Patrick's Day lands on for five years.
Mardi Gras countdown
Countdown to Mardi Gras 2027, with the Ash Wednesday and Easter dates that follow it and the 47-day Easter rule.
Hanukkah countdown
Countdown to the first Hanukkah candle of 2026, with the eighth-night date and the Hebrew-calendar rule behind it.

Guides

All guides

How to calculate hours between two times
Subtract one clock time from another by hand or in a spreadsheet, including overnight shifts, borrowed minutes and decimal hours.
Convert minutes to decimal hours
Divide minutes by 60 to get decimal hours, with a full 1–60 minute chart, the reverse conversion and spreadsheet formulas.
How to add hours and minutes
Add durations column by column and carry every 60 minutes into the hours, with clock-time, spreadsheet and time sheet examples.
Days in a year and leap years
Why a year has 365 or 366 days, how many weeks and weekdays it holds, and how the Gregorian leap-year rule works.
How to count days between dates
Count the days between two dates by hand, decide whether the end date counts, and handle month ends, leap years and deadlines.
Work hours and time card math
Total a weekly time card by hand or in a spreadsheet: daily hours, unpaid breaks, decimal hours, rounding and hours over 40.

What each calculator answers

Find the question closest to yours.

Question	Calculator
How many hours are between 9:00 AM and 5:30 PM?	Time Duration Calculator
How many hours did I work this week?	Hours Calculator
What time will it be in 8 hours?	Hours From Now
What time was it 8 hours ago?	Hours Ago Calculator
What is 1:45 plus 2:30?	Time Addition Calculator
What is the average of my lap times?	Average Time Calculator
How long is it until midnight?	Hours Until Midnight
How many days are left in 2026?	Days Left in the Year
What day of the year is it?	Day of the Year
How many days until a date?	Days Until a Date
How many days since a date?	Days Since Calculator
How many days are between two dates?	Days Between Dates
What date is 90 days from today?	Days From Today
How many days until my birthday?	Birthday Countdown
When does daylight saving time end?	Daylight Saving Time

Conventions behind the answers

Clock times use AM and PM, with a 24-hour switch wherever a time appears, and dates read month, day, year. A day count starts on the first date and stops before the last one unless you turn on “include end date.” Business days are Monday to Friday, minus the 11 U.S. federal holidays on the days they are observed, and a switch counts plain weekdays instead. The rules, sources and test cases behind every result are on the page explaining how we calculate.

Privacy

The calculators run in your browser, and the dates and times you type are never sent to a DateTimeCalcs server. Your inputs are saved in the page address, so a copied link reopens the same calculation. Analytics and advertising cookies are covered in the privacy policy.