Date and Time100% Free26 tools

Free Date and Time Calculators for Every Plan

Work out your age, the days between dates, working days, time zone conversions, work hours, sleep times and more. Everything runs in your browser, and nothing is uploaded.

Age and dates

Age CalculatorExact age in years, months and days, with next birthday countdown. Date Difference CalculatorDays, weeks, months and working days between two dates. Date Add and Subtract CalculatorAdd or subtract days, weeks, months or years from a date. Business Days CalculatorCount or add working days, skipping weekends and holidays. Days Until CalculatorDays, weeks and hours until, or since, any date. Day of the Week CalculatorFind the weekday, week number and day of year for any date. Leap Year CheckerCheck if a year is a leap year and list leap years in a range.

Time and clocks

Time Zone ConverterConvert a time between cities, with daylight saving handled. Time Card CalculatorTotal work hours from clock-in, clock-out and break times. Time Duration CalculatorAdd or subtract hours, minutes and seconds. Decimal Hours ConverterConvert between hours and minutes and decimal hours. Military Time ConverterConvert 24-hour military time to 12-hour AM/PM and back. Sleep CalculatorFind bedtimes or wake-up times based on 90-minute sleep cycles.

Health and life

Pregnancy Due Date CalculatorEstimate a due date and weeks pregnant from the last period. Zodiac Sign FinderFind your star sign, Chinese zodiac animal, birthstone and flower.

Date tools

Excel Serial Date ConverterConvert Excel serial numbers to dates and back. Julian Date ConverterConvert dates to Julian Date and MJD, and back. Week Number CalculatorISO week, US week, day of year and the dates of a week. Anniversary CalculatorYears together, next anniversary and the traditional gift. Date FormatterSee a date in ISO, US, EU, long and custom formats. DST CheckerIs DST on? See the offset and the clock change dates. FILETIME ConverterConvert Windows FILETIME to a date and back. Seconds to Hours, Minutes and Seconds ConverterConvert seconds, minutes and hours to h:mm:ss and back. Ovulation CalculatorEstimate ovulation day, fertile window and next period. Sunrise and Sunset CalculatorSunrise, sunset, solar noon and day length for any place. BPM CalculatorFind BPM from a beat count and get note lengths in ms.

How These Date and Time Tools Work

Every tool on this site runs in your browser with JavaScript. The dates and times you enter are processed on your own device. They are not uploaded, stored or logged, and no outside service is used. Time zone conversions use the time zone database that is built into your browser.

Dates are turned into exact calendar day numbers, so leap years, month lengths and weekdays are always correct. Each tool shows the answer and the working in a small table.

Which Tool Should I Use?

Dates: try the age calculator, the date difference calculator, the date calculator and the days until calculator.
Working time: use the business days calculator, the time card calculator and the decimal hours converter.
Clocks and zones: see the time zone converter, the military time converter and the time duration calculator.
Life and fun: try the sleep calculator, the due date calculator, the leap year checker and the zodiac sign finder.

More free tools: math calculators, unit converters, color tools and text tools. The time zone data comes from the IANA time zone database.