CalendarDiff

sameCal shows you the same moment in time across 11 different calendars and date-numbering systems at once — so you always know what today (or any day) looks like everywhere else.

Whether you're researching historical dates, working with international records, studying astronomy, or just curious how a date translates into another calendar system, sameCal converts it instantly and shows every system side by side.

See any date across 11 systems at once Gregorian, Julian Day, Julian Calendar, Hebrew, Islamic, Persian, Mayan, National Calendar of India, ISO 8601, Unix Epoch, and Excel Serial Day Number — all calculated from the same moment and shown together.

Convert starting from any calendar Don't just convert from Gregorian — enter a date in Hebrew, Islamic, a Mayan Long Count, an ISO week, a Julian Day number, or any of the other 11 systems, and sameCal converts it into all the others.

Browse past and future dates Not just today — pick any date and time, past or future, and see it translated across every supported calendar.

Built-in range checking Each input field shows its valid range and flags an out-of-range value immediately, so a mistyped day or month is caught before it silently rolls into the wrong date.

World clock and map See the current time across a curated set of world time zones, and tap any pin on the map for that city's local time at a glance.

Learn what each calendar means A plain-language explanation of every supported calendar — what it is, where it comes from, and how it's structured.

Copy any value instantly Tap any converted value to copy it to your clipboard, with a quick visual confirmation that it copied.

Save moments for later Bookmark any date and time zone as a Saved Moment, synced privately across your devices with your own iCloud account.

Your appearance, your choice Pick System, Light, or Dark appearance to match how you like to work.

sameCal is a straightforward, private tool: no account, no ads, no tracking. Everything lives on your device, with saved moments optionally synced through your own private iCloud account.