Unix timestamp converter

What this Unix timestamp converter does

Unix time — sometimes called POSIX timestamp or epoch time — counts seconds elapsed since 1970-01-01 00:00:00 UTC. It's the lingua franca of backends, databases, and APIs worldwide. This English-language converter takes any epoch value (10-digit seconds or 13-digit milliseconds) and outputs ISO 8601, UTC, local time, and a human-readable relative label all at once, with one-click copy for each. According to the Stack Overflow Developer Survey 2024, ISO 8601 is the most preferred date format among developers — and for good reason: it sorts lexicographically and removes ambiguity across locales. Everything runs locally via the native JS Date object — 100% client-side, your data never leaves your browser. No uploads, no tracking, no server logs.

Features

• Auto-detect seconds vs milliseconds. Paste any epoch and the tool checks digit count: 10 digits → seconds, 13 digits → milliseconds. No manual toggle needed.
• UTC and local time side by side. Seeing both simultaneously is the fastest way to catch timezone bugs — a server logging in UTC while your app displays local time is a classic mismatch.
• ISO 8601 output. Returns a fully qualified ISO 8601 string (e.g. 2024-03-15T14:30:00.000Z) that you can drop straight into API payloads or database inserts.
• Relative time label. Shows how far the timestamp is from now — "3 days ago" or "in 2 hours" — useful for quickly validating JWT exp claims or cache TTLs without mental arithmetic.
• Now button. Fills the epoch field with the current timestamp in one click, so you can confirm the current epoch seconds or use it as a baseline for duration math. Need to add or subtract days? The [date calculator](/en/date-calculator/) covers that.
• Reverse conversion. Paste an ISO, RFC 2822, or any JS-parseable date string and get back the epoch in both seconds and milliseconds instantly.

How to use the Unix timestamp converter

Paste an epoch or a date string — the tool converts in real time. Use the Now button to start from the current moment.

1. Get an epoch value. Grab one from your logs, API response, or run date +%s in a terminal (Linux/macOS). In JavaScript, Date.now() / 1000 gives you the current epoch in seconds.
2. Paste it into the epoch field. The tool detects whether it's seconds (10 digits) or milliseconds (13 digits) automatically and fills all output fields.
3. Read UTC and local time. Compare both rows to confirm your app is handling the timezone you expect. A timestamp that looks right in Chicago may be off by a day when read in Sydney.
4. Copy the format you need. Hit the Copy button next to ISO 8601, epoch seconds, or epoch milliseconds to paste it directly into your code, query, or ticket.
5. Convert a date string back to epoch. Type or paste any ISO or human-readable date into the date field and get the epoch equivalent — handy when constructing a SQL WHERE created_at > ? filter.

Common use cases

• Validating JWT claims. The exp and iat fields in a JSON Web Token (as defined in RFC 7519) are epoch seconds, but Date.now() returns milliseconds — a mismatch that causes silent auth failures. Paste the claim value here to confirm the human-readable expiry before wasting time in a debugger.
• Debugging API and database logs. Production logs often land as raw epoch milliseconds. Convert them to ISO 8601 for correlation across services, or check whether a Postgres TIMESTAMP WITHOUT TIME ZONE column silently dropped the timezone offset.
• Checking MySQL TIMESTAMP boundaries. MySQL's TIMESTAMP type overflows on 2038-01-19 03:14:07 UTC — the Year 2038 problem. If your schema stores expiry dates or scheduled jobs, paste a far-future epoch here to confirm it falls within the safe range before it hits production.
• Calculating event durations. Subtract two epoch values and you have an exact duration in seconds. For more complex date arithmetic — adding weeks or finding the difference in calendar days — the [time calculator](/en/time-calculator/) is a natural next step.
• Scheduled job and cron auditing. When reviewing a next-run timestamp from a job queue, converting it to local time tells you at a glance whether it fires at 3 AM or 3 PM. If you're also parsing the schedule expression itself, check the [cron expression parser](/en/cron-parser/).

Frequently asked questions