Network
Duration Converter
Convert seconds, minutes, hours, days, and weeks into each other, handy for TTLs, timeouts, and cache expiry.
3600 seconds (1 hour) is a common VPN rekey interval.
Runs entirely in your browser. Nothing you enter is sent anywhere.
Learn about duration units
Why this trips people up so often
Most of the systems that ask you to type a raw duration (DNS TTLs, HTTP Cache-Control: max-age, session timeouts, cron and cloud-function limits) expect plain seconds, because that's what the underlying protocol specs defined decades ago. It's an easy place to be off by an order of magnitude: typing 3600 thinking you've set a day's cache when you've actually set one hour.
Quick reference
| Seconds | Equivalent |
|---|---|
| 60 | 1 minute |
| 3,600 | 1 hour |
| 86,400 | 1 day |
| 604,800 | 1 week |
| 2,592,000 | 30 days |
| 31,536,000 | 365 days |
Common questions
Why do TTLs and cache headers use seconds instead of something friendlier? It's historical convention. Both the DNS and HTTP/1.1 specifications defined their timing fields in whole seconds, and everything built since has kept that unit for compatibility.
What's a sensible DNS TTL before a domain migration? Lower it well in advance of the change (300 seconds, or 5 minutes, is common) so that once you cut over, caches around the internet expire the old value quickly instead of holding onto it for its old, longer TTL. Raise it back to a normal value once the migration is confirmed stable.
Does "30 days" always equal exactly 2,592,000 seconds? Only as an approximation, since real calendar months vary between 28 and 31 days. Any tool converting between "months" and seconds, this one included, is using a fixed 30-day approximation, not a calendar-aware calculation.