Date & Time Toolkit
Most Date Apps Do One Thing.
DateKit Does Five.
Add or subtract time, find the difference between two dates, calculate an exact age, or pull every fact about a single day — plus pinned countdowns with private reminders, a home-screen widget, and a world clock. One toolkit, five calculators, with holiday-aware business days built into all of them.
Five Calculators, One App
DateKit isn't a single-purpose date picker with extra screens bolted on — each tab is a dedicated calculator, and they all share the same holiday and format settings.
Saved Dates & Countdowns
Pin birthdays, anniversaries, and one-time deadlines with live "days until" countdowns. Repeating dates always count down to their next upcoming occurrence. Optional local reminders notify you right on your device — DateKit never writes anything to your phone's native calendar, and your dates never leave your device.
Add & Subtract
Add or subtract days, weeks, months, quarters, years, or business days from any date — business days automatically skip weekends and holidays.
Date Difference
Compare two dates: elapsed spans, calendar-day counts, full elapsed periods, calendar-boundary crossings, and "X days/weeks/months ago" phrasing.
Age Calculator
Calculate an exact age in whole years, plus an approximate "years, months" breakdown, as of any reference date — not just today.
Date Facts
Week of year, quarter, days remaining in the month/year, first/last of week/month/quarter/year, holiday-aware business-day navigation, a leap-year flag, and an equivalent Hijri calendar date — plus links to the Nth-weekday finder, a full ISO week view, and a time-span converter.
World Clock
Pin timezones with live current time, UTC offset, and a same/different-calendar-day indicator — so you know if it's already tomorrow there.
Home-Screen Widget
An Android home-screen widget shows your nearest upcoming saved date at a glance — no need to open the app. Opt-in, off by default.
The Part Most Date Apps Skip
Adding days to a date is easy. Knowing which of those days are actually business days — for any country, any year, without a hardcoded holiday list going stale — is the part that's usually missing.
Pick your holiday calendar
US federal, UK bank, Canada statutory, or Australia public holidays, computed algorithmically for any year in Settings — plus your own custom holidays on top. Not a static list that expires.
Business days respect it
Add/Subtract, Difference, and Facts all skip weekends and the holidays from your chosen calendar when you ask for business days.
Formats follow your locale
ISO, US, EU, or verbal date display applies app-wide, and every result count uses your device's digit grouping.
Copy or share, no retyping
Most result cards support copy-to-clipboard and native share, so a calculation doesn't dead-end on the screen it was run on.
What DateKit Actually Does
No hand-waving about what's "smart." Here's the actual behavior.
- ✓Holidays computed, not hardcoded. US federal, UK bank, Canada statutory, and Australia public holidays are calculated algorithmically for any year — plus your own custom holidays — so business-day math never goes stale.
- ✓Repeating dates count to next. A saved birthday or anniversary always shows the countdown to its next occurrence, not the one that already passed.
- ✓Unsigned, locale-correct output. Every difference is shown as a magnitude, formatted with your device's digit grouping — not a raw signed integer.
- ✓One format, everywhere. ISO, US, EU, or verbal date display is a single Settings toggle that applies across every calculator.
- ✓Six platforms, one codebase. Android, iOS, Windows, macOS, Linux, and Web, all from a single Flutter app.
- ✓Reminders stay private, on-device. Optional local notifications for saved dates are scheduled directly on your device — DateKit never creates an entry in your phone's calendar app and never uploads your dates anywhere.