Directory
Every calculator and converter on EpochKit, in one place. All of it runs in your browser — nothing you type is ever uploaded.
Core
The main toolkit — a live instrument panel plus the converter, batch tool, timezone comparison, and countdown builder.
Convert Unix time to a readable date and back, with auto-detected precision.
Convert a whole list of timestamps or dates at once, export as CSV.
Copy-paste epoch time snippets for common languages.
Live clocks across any set of cities or IANA zones.
Build a live countdown to any date, with quick presets.
Get a two-line embed code for a live countdown on your own site.
Calculators
Everyday date math — differences, shifts, ages, and calendar facts.
The exact number of days, weeks, and months between two dates.
Shift any date forward or backward by a day count.
Simulate a different system date and batch-shift a whole list of dates.
A live countdown to any date, or a count of days since it passed.
Exact age in years, months, and days, plus total days lived.
Look up the current age range for any birth year, 1940–2020.
Working days between two dates, since/until a date, or add N business days from today.
The next occurrence of a yearly, monthly, or weekly event.
What weekday any past or future date falls on.
The ISO 8601 week number for any date.
Is a given year a leap year, and which years come next.
Every year in range, marked and linked to its own page.
The exact gap between two birth dates, in years, months, and days.
Which named generation a birth year falls into — Gen Z, Millennial, and more.
How old you were, or will be, on your birthday in any year.
Which fiscal quarter a date falls into, for any fiscal year start month.
YYYY-Www-D format, converted to and from a calendar date.
The 2nd Tuesday, the last Friday — the exact date, for any month.
Seconds, minutes, hours, days, weeks, months, and years, all at once.
Days until your next birthday, and which age you're turning.
The exact date you'll reach your target retirement age.
Exact years of service, and your next anniversary date.
How many full weekends are left in the year, or until any date.
Sky & Sun
Time-of-day and seasonal calculations tied to the sun and moon, not the clock.
The moon's phase for any date, past or future.
Sunrise and sunset time for any date and any location.
Hours of daylight for any date and location, and how it's changing.
Holidays
Holidays whose dates genuinely require calculation, not just a fixed day on the calendar.
Live Computus calculation for any year, 1583–2399.
2025 through 2031, with a live countdown.
2025 through 2029, with a live countdown.
2025 through 2029, with a live countdown.
Estimated dates, with an honest explanation of why they can't be fixed in advance.
A live countdown to the next full moon.
Exact UTC times, sourced from published astronomical tables.
Calculated live from the calendar, not a fixed list.
The next date that reads the same forwards and backwards.
Holidays
Full national holiday calendars, calculated live for any year — not copied from a static list.
All 11, any year, with the weekend-observed-date rule applied.
England & Wales, any year, with substitute days applied.
The federal list, any year.
The nationally-common list, any year.
The nationwide list, any year.
Jours feries, any year.
Including the Happy Monday System holidays.
The three truly national holidays, any year.
The national list, any year.
The national list, any year, plus the patron-saint-day quirk.
Including Carnival's unofficial-but-universal status.
Including the 2006 Monday-shift reform.
Through 2028, including Seollal and Chuseok.
Including King's Day's weekend-shift rule.
One of Europe's more Easter-dependent calendars.
Including the Sunday-to-Monday shift rule.
Mondayisation rules plus the official Matariki date schedule.
All 13 official red days, any year — no weekend shifting.
All 12 official holidays, no weekend-shift rule.
10 official helligdage, reflecting the 2024 reform.
13 official holidays, incl. floating Midsummer & All Saints'.
Both dates, calculated live from the actual rule.
2nd Sunday of May, calculated live.
3rd Sunday of June, calculated live.
Calculated from the real rule, including the century exception.
Extract the embedded creation timestamp from a video ID.
Extract the embedded creation timestamp from a media ID.
Work & Payroll
Total hours worked from clock-in/out times, with break deduction.
HH:MM ⇄ decimal hours, for payroll and invoicing.
See how a punch time rounds under common payroll rules.
Decode the day-of-year code stamped on packaged food.
The ideal nap length and wake time, by sleep-cycle science.
Consumer & Legal
Exact expiration date from a purchase date and warranty length.
The exact last day you can return an item.
Your next billing date, for any cycle.
The exact end date of a required notice period.
Travel & Work
Check your passport against the common travel rule.
Exact days remaining before a visa expires.
Estimated adjustment time by zones crossed and direction.
Exact end date from a job start date and length.
Milestones
Years married, next anniversary, and the gift for that year.
A full milestone-by-milestone planning schedule.
Track days since your quit date, and money saved.
More
Confirmed host cities and dates through 2032.
"3 hours ago" style output, plus how to build it yourself.
Ready-made patterns for common date formats, with a live tester.
A region-by-region overview of where clocks still change.
Confirmed solar and lunar eclipse dates through 2027.
A live countdown to the next new moon.
The next calendar month with two full moons.
Live countdown to the next federal Election Day.
Compact, URL-safe timestamp encoding, decoded either direction.
Every format code, with a live tester.
Where Java's Quartz scheduler syntax diverges from standard cron.
Every version's end-of-life date, with a live countdown.
Every version's end-of-life date, with a live countdown.
Every LTS version's end-of-life date, with a live countdown.
Every LTS release's standard support end date, with a live countdown.
Every version's end-of-support date, with a live countdown.
Every major version's end-of-life date, with a live countdown.
LTS Premier and Extended support dates, with a live countdown.
Every major version's end-of-life date, with a live countdown.
Regular support and LTS end dates, with a live countdown.
More
Find your Western zodiac sign by birth date.
Animal and element, correctly accounting for the Chinese New Year boundary.
The real research-based formula, not the ×7 myth.
The standard veterinary age chart.
Your next several pay dates, and 26- vs 27-paycheck years.
Regular, overtime, and total gross pay from an hourly rate.
Upcoming paydays for any pay frequency.
Exact partial-month rent for a mid-month move.
Exact lease end date and notice deadline.
This year's actual federal filing deadline.
Standard clinical estimate from your last period.
Estimated fertile window from cycle data.
A straight answer, plus a countdown if not.
For Developers
Decode a JWT's iat/exp/nbf claims and see if it's expired.
Build a downloadable .ics file for any calendar app.
iCalendar recurrence syntax, built or decoded in plain English.
Excel/Sheets serial number ⇄ real date, 1900 vs 1904 systems.
Time
Clock-time math and everyday time questions, as opposed to calendar-date math.
Hours and minutes between two clock times, including overnight shifts.
Bedtimes or wake times aligned to 90-minute sleep cycles, plus quick links for 16 common wake-up times.
The current local time in major cities around the world, live.
Customizable focus and break intervals for deep work sessions.
Precise elapsed-time tracking with lap splits.
Days until Christmas, New Year, Halloween, or any custom date.
Reading
Longer-form explainers for the concepts behind the tools.
Current epoch and conversion snippets across 29 languages, plus individual deep-dive pages for each.
Why Unix time breaks on 32-bit systems, with a live countdown.
Scheduling
Free alternatives to paid or signup-gated meeting planners, plus a couple of genuine gap-fillers.
Convert one specific time from any zone to any other, DST included.
Look up the live time in any of the 50 states, organized by timezone.
60+ major world cities, organized by region.
Compare timezones on one grid, find overlapping hours, no signup.
When clocks change for any timezone, calculated live.
Search any abbreviation, or jump straight to one of 40 individual pages.
12-hour ⇄ 24-hour time, plus NATO zone letters.
Search every Area/Location timezone identifier, with live current offset.
Developer
Scheduling, integration, and messaging utilities for people who write code.
Build a schedule, or paste one for a plain-English explanation and next run times.
40+ ready-made patterns, each explained with next run times.
Excel, .NET ticks, Mac HFS+, GPS time, and Julian day number.
One date, rendered in ISO, US, EU, RFC 2822, and more, at once.
Paste a string, check it's valid, and see exactly what's wrong if not.
Bulk random dates and timestamps for test fixtures and seed data.
Paste raw log text, find and convert every timestamp buried inside.
Paste a JSON payload, find and convert every timestamp field, nested included.
Extract the creation timestamp from a Discord or Twitter/X ID.
Extract the creation timestamp from a MongoDB document ID.
Dynamic <t:> tags in all 7 Discord display formats.
Decode a permalink's p1234567890123456 into a date, or build dynamic message markup.
NTFS, registry, and Win32 API timestamps, converted either direction.
Decode browser history and cookie timestamps.
pwdLastSet, lastLogonTimestamp, and accountExpires, decoded.
Core Data and Safari's seconds-since-2001 timestamp format.
The week-and-day format used in GNSS receivers, including the 1024-week rollover.
Seconds, milliseconds, microseconds, and nanoseconds — auto-detected.
The seconds-since-1900 format behind network time sync.
A live countdown to the 32-bit Unix time overflow.
Convert cron syntax to OnCalendar=, with the AND/OR gotcha flagged.
P3Y6M4DT12H30M5S, decoded to plain English, or built from scratch.
2h 30m ⇄ total seconds, minutes, and hours.
Every leap second added to UTC since 1972.
More tools are in progress — check the sitemap for the latest additions.