Time

Compute Easter Sunday for any year using the standard Gregorian computus — or the Julian (Eastern Orthodox) variant.

Split a date range into N equal intervals — get the start/end of each chunk or just the boundary dates between them.

Pick a pattern (weekly, every Nth weekday of the month, on the same day of month, every N days) and see the next N actual dates.

Type a 5-field cron expression and see the next N times it will fire — local time, including weekday + day-of-month dual semantics.

Type any date (ISO, RFC, Unix epoch, locale) and see it rendered in 14+ standard formats side by side.

Convert a duration between human ("1h 30m"), clock (1:30:00), ISO 8601 (PT1H30M), and raw seconds/minutes/hours/days.

Run focused 25-minute work sessions and short / long breaks, with a circular timer, sound alerts, and a daily counter.

Add or subtract years, months, weeks, days, and business days from any date — or find the difference between two dates.

See several time zones side by side with live updates and offset differences from your local time.

Calculate the exact difference between two date-times, broken down into days, hours, minutes, and seconds.

Convert a date and time between any two world timezones, including DST.

Convert Unix timestamps to dates and dates back to timestamps.

Plot the classic biorhythm cycles — physical (23 days), emotional (28 days), intellectual (33 days), plus four secondary cycles — for any birth date and target date. Interactive ±15-day chart, current percentage per cycle, and critical-day list.

How old are you on Mercury, Mars, Saturn or Pluto? Enter your birth date and see your age plus next-birthday countdown for every planet in the Solar System.

Convert between solar (Gregorian) and East Asian lunisolar calendar dates. Returns zodiac animal and ganzhi (heavenly-stem/earthly-branch) year name. Covers 1900-2099.

Look up the day of the week for any date — supports multiple dates at once, multilingual day names, ISO week numbers, day-of-year, and leap-year flag.

Convert a timestamp between seconds, milliseconds, microseconds, and nanoseconds since Unix epoch. Auto-detects precision, also outputs ISO, RFC 2822, and relative time.

Convert any UTC moment to Greenwich and Local Mean/Apparent Sidereal Time, Julian Date, Modified Julian Date and Earth rotation angle — for telescope alignment, astronomical observation and astro-software.

Convert a musical tempo (BPM) to note durations in milliseconds — straight, dotted and triplet — for whole, half, quarter, 8th, 16th, 32nd, 64th notes. Includes tap-tempo and common delay presets for echo/reverb pre-delay setup.

Pick any date and get the lunar phase name, illumination percentage, age in days since the last new moon, an SVG illustration of the current crescent / gibbous shape, and the dates of the next new moon and full moon — over a customisable look-ahead window.

Compute the Equation of Time (the gap between mean solar time and apparent solar time) for any date, plus the longitude correction to your civil time zone, the actual local solar noon, and the 'sundial reads X minutes ahead or behind the clock' for sundial calibration.

Convert a single moment in time between 11 historical epoch formats: Unix seconds and ms, NTP, Windows FILETIME, .NET DateTime Ticks, Mac HFS+, Apple Cocoa CFAbsoluteTime, Excel 1900 and 1904 serial, ISO 8601, and RFC 2822.

Convert any date to its ISO week number (and back) — get the Monday-start / Sunday-end of that week, ISO year, day-of-year, and how many weeks the year has.

For any date, get the calendar quarter, fiscal quarter (with a configurable fiscal-year start), days into / left in the quarter, and the quarter's start/end dates.

Add timezones with each participant's working hours, see the 24-hour overlap grid, and read the best meeting slot in everyone's local time.

Add N working hours to a start datetime — skip weekends and holidays, respect a per-day work window, get the landing timestamp and a per-day breakdown.

Type a birthdate, get a live ticking countdown to the next birthday — plus exact age, days since born, hours lived, and the rare golden birthday year.

Paste a list of `YYYY-MM-DD` dates (with optional counts) and render a GitHub-style yearly heatmap — palette, week start, streaks, hover counts.

Convert between a Gregorian date and a Julian Day (JD), Julian Day Number (JDN), Modified Julian Day (MJD), Reduced/Truncated JD, and Unix timestamp.

Format any past or future date as `2 hours ago`, `in 3 days`, `last month` — in 12 locales, three styles (long/short/narrow), with `numeric: auto` for the natural-language phrasing.

A precise stopwatch with laps and a countdown timer with an alarm.

Count the business days between two dates — pick which weekdays count as weekend and paste a list of holidays to exclude.

Compute sunrise, sunset, solar noon, and all three twilight phases for any latitude, longitude, and date — using the NOAA solar algorithm.

Count the days between two dates, or the countdown to a target date.