Date & Time tools
Ages, business days, world clocks, durations.
Time formats at a glance
| Format | Example | Use it for |
|---|---|---|
| Unix (seconds) | 1716883200 | Database timestamps, JWT exp. |
| Unix (milliseconds) | 1716883200000 | JS Date.now(), API responses. |
| ISO 8601 UTC | 2026-05-28T09:00:00Z | Logs, audit trails, APIs. |
| RFC 3339 | 2026-05-28T09:00:00-04:00 | ISO + offset; same idea, stricter. |
Always store UTC. Convert to local time only at display.
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Age Calculator
Calculate exact age in years, months, days — plus total days lived, day of birth, and next birthday.
Business Days Calculator
Count business days between two dates, or add N business days — with US or UK holiday awareness.
World Clock & Timezone Converter
See the current time in any timezone, or convert a moment from one zone to another.