Convert between seconds and days in either direction.
How it works
A standard day has 86,400 seconds (24 × 60 × 60), so 1 day = 86,400 s. Enter a value in either field and the other updates instantly.
What this does not include
This uses a fixed 86,400-second day. It doesn’t account for leap seconds, which are occasionally added to keep clock time aligned with Earth’s rotation and make a small number of real days slightly longer than 86,400 seconds.
How to use this calculator
- Enter a value in seconds or days.
- The other field updates automatically.
Why 86,400 specifically?
It comes from the standard division of a day into 24 hours, each hour into 60 minutes, and each minute into 60 seconds: 24 × 60 × 60 = 86,400.
What are leap seconds?
Occasional one-second adjustments added to civil time to keep it synchronized with the Earth’s slightly irregular rotation — they’re rare enough that this calculator’s fixed 86,400-second day is accurate for virtually all everyday purposes.
Is this the same as converting seconds to a calendar date?
No — this converts a duration (a span of time) between units; converting to an actual calendar date would need a specific starting point to count forward or backward from.
