140 tools

Every date and time calculation, on its own page

The workbenches on this site answer broad questions. These answer small ones. How many work days are left? What phase was the moon in? When is the third Monday? What does that cron line do? It all runs in your browser, and each page keeps its state in the address bar.

Search 140 tools

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Browse by what you are trying to work out

Twelve areas. Every tool lives in exactly one of them.

Date difference & duration

How far apart two instants are — in whichever unit you need, counting every day or only the working ones.

Includes Date Difference Calculator, Time Difference Calculator, Days Between Dates and 11 more.

Age & anniversaries

Exact ages, next birthdays, anniversaries and the odder age scales.

Includes Age Calculator, Exact Age Calculator, Birthday Countdown and 10 more.

Add & subtract

Move a date forwards or backwards by a span, with the calendar's rules applied.

Includes Add Days to Date, Add Weeks to Date, Add Months to Date and 12 more.

Calendar tools

Printable calendars, week numbers, quarters, fiscal years and weekday finders.

Includes Calendar Generator, Printable Calendar, Yearly Calendar and 11 more.

Unix time & epochs

Seconds, milliseconds, microseconds and nanoseconds, in both directions.

Includes Unix Timestamp Converter, Timestamp to Date, Date to Timestamp and 6 more.

Time zones

Convert between zones, watch a board of cities, and find the hour that suits everyone.

Includes Time Zone Converter, World Clock, UTC Converter and 7 more.

Countdowns & timers

Count down to a moment, or time what you are doing right now.

Includes Countdown Timer, Stopwatch, Pomodoro Timer and 6 more.

Work & business time

Timesheets, shifts, overtime and billable hours, added up correctly.

Includes Work Hours Calculator, Shift Calculator, Overtime Calculator and 4 more.

Sun & moon

Sunrise, sunset, the golden hour and the phase of the moon, anywhere on Earth.

Includes Sunrise Calculator, Sunset Calculator, Golden Hour Calculator and 7 more.

Formatting & parsing

Render an instant in any pattern or locale, and read one back out of text.

Includes Date Formatter, Time Formatter, ISO Date Converter and 7 more.

Scheduling

Recurring dates, time slots, rotations and calendar files.

Includes Meeting Time Finder, Best Meeting Time Calculator, Recurring Date Generator and 7 more.

Converters & validators

Julian days, Excel serials, GPS time, cron expressions and format validators.

Includes Julian Date Converter, Julian Day Number Calculator, Modified Julian Date Converter and 16 more.

The ones people reach for

Thirty-odd tools that cover most of what anyone actually comes here to work out.

Date Difference CalculatorThe difference, the duration, the interval — the same question under three names. Enter two dates and get the gap in every unit at once: years, months and days as a person would say it, and the exact totals underneath.

Time Difference CalculatorTwo clock times or two full timestamps, and the difference in hours, minutes and seconds — including the overnight case, where the end time is smaller than the start.

Days Between DatesA plain day count, with the weekday split beside it and the inclusive answer stated too — because half the time "days between" means one more than subtraction gives.

Business Days CalculatorNon-working days out, your own public holidays out, and every removed day listed — so you can see exactly what the count is made of rather than trusting a number.

Age CalculatorYour age in years, months and days, worked out the way a birthday works — plus the totals in weeks, hours and seconds, and how long until the next one.

Birthday CountdownA live countdown to the next one — days, hours, minutes and seconds, ticking down, with the weekday it lands on.

Add Days to DateAdd any number of days to a date and get the answer with its weekday, plus the same date counted in working days for anything with a deadline attached.

Subtract DaysDays taken off a date, with the weekday, and the working-day answer beside it for anything counted backwards from a deadline.

Calendar GeneratorA clean grid for any month, with week numbers down the side, public holidays marked, and a start-of-week that follows your part of the world rather than an assumption.

Week Number CalculatorThe ISO week for any date, the US week beside it, the Monday-to-Sunday dates the week covers, and how many weeks the year has.

Leap Year CheckerThe answer, the rule that produced it, the next and previous leap years, and the century exceptions that catch people out.

Day of Week CalculatorThe weekday for any date, past or future, plus its week number, day of the year, and which weekday that date falls on in the surrounding years.

Unix Timestamp ConverterPaste a timestamp and get the date; paste a date and get the timestamp. The precision is detected from the digit count and shown so you can override it, and a number that is not Unix time is checked against the other eleven epochs too.

Timestamp to DateOne field, one answer — the timestamp as a date and time in your zone, in UTC, and in about thirty other encodings you might need to paste somewhere.

Date to TimestampType a date any way you like — ISO, a slash date, `next friday`, `now` — and get the timestamp in seconds, milliseconds, microseconds and nanoseconds.

Time Zone ConverterOne instant, two clocks. Pick the zones, enter a time, and see what it reads in the other — with the date shift, the offset difference and any daylight-saving trap called out.

World ClockA live board of cities with their offsets, their daylight-saving state, and a read on whether it is morning, working hours or the middle of the night there.

Countdown TimerSet a duration or a target time and let it run, with a sound and a title flash when it finishes. Nothing is installed and nothing is uploaded — the timer is the page.

StopwatchStart, stop, lap, reset. Millisecond resolution, lap splits with the difference from the previous one, and the whole list copyable as text.

Work Hours CalculatorStart, finish, break — for one shift or a whole week. Totals in hours and minutes and in decimal hours, with overnight shifts handled and nothing sent anywhere.

Shift CalculatorOne shift at a time: length, paid hours after breaks, whether it crosses midnight, and where it sits in a rotating pattern.

Sunrise CalculatorSunrise for any place and date, with the twilights before it, the bearing the sun comes up on, and how much earlier or later it is than yesterday.

Sunset CalculatorSunset for any place and date, the twilight that follows, the bearing it goes down on, and how long you have before it is properly dark.

Golden Hour CalculatorThe two windows a day when the sun is low and the light is warm — with the exact start and end, and how long you actually get, which near the equator is not an hour.

Moon Phase CalculatorThe phase for any date, drawn as well as named, with the illuminated fraction, the moon's age in days, and the dates of the next new and full moons.

Date FormatterOne date, every common output at once — ISO, RFC, SQL, filename-safe, spoken English — plus a pattern field for anything the list does not cover.

ISO Date ConverterThe extended form, the basic form, the week date and the ordinal date — all four ISO 8601 shapes for one instant, plus a parser for reading them back.

Meeting Time FinderAdd everyone's city, set the working hours, and see every hour of the next few days scored by how many people it suits — with the local time for each.

Excel Date ConverterA spreadsheet serial to a calendar date and back, in both the 1900 and 1904 systems — with the phantom leap day of 1900 flagged where it matters.

Cron Expression GeneratorPick a schedule and get the expression, described back to you in English and with its next five runs shown — so you can see what it does before it does it.

Cron Expression ParserPaste an expression and get it back in English, field by field, with its next runs, how often it fires, and any trap it has walked into.