Date & Time Tools
Unix timestamp converters, time zone converter, date difference calculator and countdown timers for scheduling and development work.
54 free tools
Date Difference Calculator
Calculate the exact difference between two dates in years, months and days, plus total days, weeks, hours and minutes. Free, fast and private.
Countdown Timer
Free online countdown timer. Count down to any date and time or start a quick timer in minutes, with start, pause, reset and a live progress bar.
Time Zone Converter
Convert any date and time between world time zones. See UTC offsets, daylight saving handled automatically, and compare multiple zones at once.
Timestamp Converter
Convert timestamps to human-readable dates and dates back to timestamps. Auto-detects seconds vs milliseconds, shows local, UTC and ISO 8601 formats.
Unix Timestamp Converter
Unix epoch time converter with live current epoch, seconds, milliseconds and microseconds support, and a reference table of common epoch values.
Add or Subtract Days Calculator
Add or subtract days, weeks, months or years from any start date and instantly see the resulting date with its weekday. Free, fast and fully private.
Business Days Calculator
Count business (working) days between two dates, excluding weekends and your own holiday list. See working days, weekend days and total days at a glance.
Week Number Calculator
Find the ISO 8601 week number for any date, plus the Monday-to-Sunday date range of that week and the day of the week. Free and 100% in-browser.
Day of Year Calculator
Find the day-of-year number (1–366) for any date, the days remaining in the year, and how far through the year you are as a percentage. Free and private.
Days Until Date Calculator
Count down from today to any future date: see the exact number of days, plus a weeks and a years/months/days breakdown. Free, instant and private.
Leap Year Checker
Check whether any year is a leap year, understand the divisible-by-4/100/400 rule, and see the next and previous leap years. Free and fully in-browser.
Time Duration Calculator
Add or subtract hours, minutes and seconds, or sum a list of durations into a total shown in h:m:s and in total seconds. Free and 100% in-browser.
Hours Between Times Calculator
Calculate the hours and minutes between two clock times, even across midnight, with optional break deduction for timesheets. Free, accurate and private.
Weekday Finder
Find what day of the week any past or future date falls on, and look up the Nth weekday of any month, like the 3rd Monday. Free and fully in-browser.
Months Between Dates Calculator
Count the full calendar months between two dates plus the leftover days, with the total months and total days also shown. Free, accurate and private.
Age in Months Calculator
From a birth date, get exact age in years, months and days plus total months and total days lived. Great for babies and milestones. Free and private.
Quarter of Year Calculator
Find the calendar quarter (Q1–Q4) for any date, its start and end dates, and how many days you are into and left in the quarter. Free and in-browser.
Date Format Converter
Convert any date between ISO 8601, US, European, RFC 2822 and custom token formats. Includes a bulk mode that reformats a whole pasted list at once.
Time Calculator
Add and subtract a chain of times and durations in hh:mm:ss with automatic carry across day boundaries, plus a decimal-hours read-out for payroll.
Military Time Converter
Convert 12-hour AM/PM times to military 24-hour time and back, with a full 0000–2300 reference chart and bulk conversion of a pasted list.
Sunrise Sunset Calculator
Calculate sunrise, sunset, solar noon, day length and civil twilight for any latitude, longitude and date using the NOAA solar position algorithm.
Moon Phase Calculator
Find the moon phase for any date with illumination percentage, moon age in days, a drawn moon disc and the dates of the next new and full moons.
Zodiac Sign Calculator
Enter a birth date to find its western zodiac sign, with element, modality, ruling planet, date range and a warning if the date falls on a cusp.
Chinese Zodiac Calculator
Find your Chinese zodiac animal and element from your birth date, using real Lunar New Year dates so January and February births resolve correctly.
Weeks Between Dates Calculator
Count the exact number of weeks and remaining days between two dates, with an option to count working weeks that exclude Saturdays and Sundays.
Julian Date Converter
Convert between Gregorian dates, Julian Day Number, Modified Julian Date and the 5-digit YYDDD Julian code used on manufacturing date stamps.
Decimal Hours Converter
Convert hours and minutes to decimal hours and back for payroll and invoicing, with rounding to the nearest 1, 5, 6, 10 or 15 minutes and a bulk list mode.
Pomodoro Timer
A configurable Pomodoro timer with work, short break and long break cycles, session counter, completed-cycle log and an optional end-of-session beep.
Online Stopwatch
A precise online stopwatch with lap splits, fastest and slowest lap highlighting, keyboard shortcuts and CSV download of the whole lap table.
Meeting Time Planner
Compare a 24-hour grid across several time zones at once, with working hours shaded, to find the meeting slot that suits everyone on the call.
ICS Calendar File Generator
Build a valid .ics calendar file with UID, DTSTAMP, TZID or UTC times, a reminder and recurrence, then download it for Google Calendar, Outlook or Apple.
RRULE Generator and Tester
Build an RFC 5545 recurrence rule from plain controls or paste one to test it, then read the next occurrences expanded date by date in your browser.
Date Sequence Generator
Generate a list of dates from a rule — every N days, only chosen weekdays, or the nth weekday of each month — skipping weekends and holidays you paste in.
Printable Calendar Generator
Draw a printable month or full-year calendar with ISO week numbers and your own events, then export a print-ready PNG or PDF at A4 or Letter proportions.
Add Business Days Calculator
Add or subtract working days from a date, skipping the weekend days you choose and any holidays you paste in, and see every single day that was skipped.
Daylight Saving Time Calculator
Find the exact daylight saving start and end instants for any IANA time zone and year, with the offsets on either side and the rule each change follows.
ISO 8601 Date Converter
Parse and convert ISO 8601 dates between calendar, basic, week and ordinal forms with the Unix timestamp, plus a full ISO 8601 duration converter.
Fiscal Year Calculator
Map any date to its fiscal year, quarter, period and week for any fiscal start month, including retail 4-4-5, 4-5-4 and 5-4-4 week-based calendars.
Age Difference Calculator
Work out the exact age gap between two birth dates in years, months and days, plus each person's age and the date the older one matched the younger.
Date Range Overlap Calculator
Compare two or more date ranges to find the shared interval, every pairwise overlap, the merged coverage and the gaps, with an inclusive end-date toggle.
Sprint Date Calculator
Generate an agile sprint schedule with start, end, review and retro dates, the working days in each sprint, and CSV or ICS export for the team calendar.
Year Progress Calculator
See how much of the year, quarter, month, week and day has elapsed as a live percentage, with the days remaining and copyable text progress bars.
Nth Weekday of the Month Calculator
Turn a rule like the third Monday of January into a real date for any year, or take a date and find out which occurrence of its weekday it is.
Easter Date Calculator
Work out Easter Sunday for any year from 1583 with the Gregorian computus, plus Orthodox Easter and every movable feast from Ash Wednesday to Pentecost.
US Federal Holidays Calculator
List all eleven US federal holidays for any year with observed dates, weekend shifts applied under EO 11582, and one-click CSV or ICS calendar export.
Golden Hour Calculator
Find golden hour and blue hour times for any place and date, with start and end bearings, window lengths and solar noon from the NOAA solar model.
Equinox and Solstice Calculator
Exact UTC instants of the March and September equinoxes and the June and December solstices for any year, with local times and season lengths.
Hijri Date Converter
Convert Gregorian dates to Hijri and back using the tabular civil Islamic calendar, with Arabic month names, weekday and a sighting adjustment.
Persian (Shamsi) Calendar Converter
Convert Gregorian dates to the Solar Hijri (Shamsi) calendar and back, with Persian month names, weekday, day of year and leap-year status.
GPS Week Number Calculator
Convert UTC to GPS week, day of week and time of week, or back again, with configurable leap seconds and both 10-bit and 13-bit rollover values.
Interval Timer (HIIT and Tabata)
A free online HIIT and Tabata interval timer with work and rest phases, rounds, sets, countdown beeps and a large high-contrast display.
Retirement Date Calculator
Work out your exact retirement date from your date of birth and chosen retirement age, then count the years, days, working days and pay periods left.
Business Hours Calculator
Count working hours between two timestamps against your opening hours, working days, lunch break and public holidays — the arithmetic behind SLA clocks.
Shift Schedule Generator
Build rotating shift rosters from 4-on-4-off, 2-2-3 Panama, DuPont or a custom pattern, with a month calendar per crew and CSV or ICS export.