How this works
Pick any date — past or future — and the calculator works out the gap to right now, ticking once a second. If the date is in the future you get a countdown ("3 years, 2 months, 18 days until …"); if it's in the past you get an elapsed counter ("… ago"). The result also shows totals in days, weeks, hours and minutes — handy for milestones, anniversaries, project deadlines, or just satisfying curiosity.
The formula
The calendar walk matches how people speak: "3 years, 2 months, 15 days" rather than "1,170 days". The total-days/weeks/hours/minutes figures come from the millisecond difference divided by the appropriate constant — they're for cases where you need a single number to feed into another calculation, not a phrase. Time component (HH:MM:SS) updates live; the y/m/d portion is still strictly correct because seconds carry up through the calendar borrow chain.
Example calculation
- Today is 28 April 2026 at 14:30. Target: 25 December 2026 at 00:00.
- Calendar walk: 7 months and ~26 days difference, with hours rolling back through the borrow chain.
- Headline: "0 years, 7 months, 26 days until …", with HH:MM:SS counting down live.
- Totals: ~241 days, ~34 weeks, ~5,800 hours, ~349,000 minutes.
Frequently asked questions
Why does the seconds counter sometimes skip a value?
Browser tabs in the background throttle setInterval to ~1 Hz at best, and on mobile may pause it entirely when you switch apps. When the tab regains focus, the next tick recalculates from the wall clock — so you'll see it jump straight to the correct value rather than catching up second-by-second. The y/m/d portion stays accurate the whole time; only the HH:MM:SS display visibly skips.
Does the calculator handle time zones?
It uses your browser's local time zone for both ends — "now" comes from your device clock, and the target date you enter is interpreted in that same zone. So if you set midnight on New Year's Eve, you'll see the countdown to midnight in your local time, not UTC. If you need a specific zone (e.g. "midnight in Tokyo"), enter the corresponding local time of your zone manually — there's no built-in zone picker yet.
Can I share a link to a specific countdown?
Not yet via URL parameters — the calculator state lives in component state, not the address bar. The Copy button puts a snapshot on your clipboard so you can drop it into chat. URL-encoded preset dates (e.g. ?d=2026-12-25) are an obvious next step; if you want them, let us know and we'll prioritise.