How many days until Halloween?
This page counts the days, hours, minutes and seconds until 31 October begins in your own time zone, the usual meaning of "days until Halloween". It updates every second, needs nothing typed, and as soon as the day has passed it starts counting to next year's 31 October by itself.
Why Halloween is always 31 October
Halloween is the eve of All Saints' Day (All Hallows), which the Western church fixed on 1 November, so Halloween is 31 October every year regardless of weekday. Its older roots are usually traced to Samhain, the Celtic festival marking the end of harvest, which is why the imagery is about the turn of the season and the dead.
The weekday matters for planning: trick-or-treating and parties move to the nearest weekend when the 31st falls midweek, and some towns announce official trick-or-treat hours. The countdown here always targets the real date; for a party on the Saturday before, make a custom countdown.
Which time zone does the countdown use?
Midnight in the time zone your device reports, so a reader in Seoul and a reader in Lisbon each see the hours to their own midnight, nine hours apart. The target is written under the digits with its zone abbreviation, for example "KST (UTC+09:00)", so you can check it at a glance.
To count to Halloween somewhere else, such as a family video call at midnight in another country, make a custom countdown on the countdown page with that zone selected; its share link carries the exact moment, and anyone who opens it sees the same instant converted to their clock.
It stays exact in the background and rings at midnight
The remaining time is recomputed from the clock every time the page draws, so a background tab or a locked phone cannot make it drift; when you come back, the digits are simply right. Over long spans the day count is a true count of 24-hour periods, which is why a daylight-saving change in between can show as 84 days 23 hours rather than 85.
During the last 100 hours the alarm is pre-scheduled on the browser's audio clock and backed by a system timer and a desktop notification, so if the page is open at midnight it rings on time, even in a background tab on a computer. Choose the sound and volume under Alarm; on an iPhone keep the tab in front, because Safari pauses hidden pages.
On the day itself, and the year after
From midnight the page shows a greeting instead of the countdown, with how long ago the day began, and a small line with the days until next year's Halloween. Twenty-four hours later it switches back to counting, so a bookmark or a classroom display never needs resetting.
Costumes, pumpkins and the last week
A carved pumpkin lasts three to five days before it sags, so carve when the display shows 3 days or less; uncarved pumpkins keep for weeks. Costume shops and online orders get crowded in the final ten days, which is when the count on this page is most useful as a nudge.
For a classroom or a shop window, full-screen mode (F) shows just the digits and the date. On the night itself, the timer page is handy for timing door-to-door rounds, and the interval timer for a game of musical chairs.
Other countdowns and time tools
The countdown page counts to any date and time you choose, in any time zone, and also counts the days since a past date. For a length of time starting now, such as 10 minutes, use the timer; the stopwatch measures how long something takes. New Year, Christmas, Halloween and Valentine's Day each have a page like this one.