Free Unix Timestamp Converter

Convert unix timestamps (epoch time) to human-readable dates and back. Seconds vs milliseconds are detected automatically, and results include local time, UTC, ISO 8601, and relative time. Everything runs in your browser.

Timestamp → Date

Date → Timestamp

About this Unix Timestamp Converter

Unix time (also called epoch time or POSIX time) counts the number of seconds elapsed since 00:00:00 UTC on 1 January 1970. It is the universal machine format for dates: databases store it, APIs exchange it, log files are full of it, and JWTs use it for expiry claims. The catch is that a raw number like 1752480000 means nothing to a human — and that is where this converter comes in. Paste any timestamp and get the local time, UTC time, ISO 8601 string, and a plain-English relative time ("3 days ago", "in 2 hours") instantly, entirely in your browser.

Seconds vs milliseconds — the classic bug

Unix timestamps come in two common flavors. POSIX systems, most databases, and JWT claims use seconds; JavaScript's Date.now(), Java's System.currentTimeMillis(), and many logging systems use milliseconds. Mixing them up produces dates in 1970 (milliseconds treated as seconds are about 20 days after the epoch) or tens of thousands of years in the future (seconds multiplied by 1000 twice). This tool auto-detects the unit: values above 1e12 are treated as milliseconds, everything else as seconds, and the detected unit is always shown so you can sanity-check the assumption.

Which output format should you use?

• ISO 8601 (2026-07-14T08:00:00.000Z) — the best choice for APIs, logs, and anything machine-readable. It sorts lexicographically and is unambiguous about timezone.
• UTC string — human-readable and timezone-neutral; good for comparing events across servers in different regions.
• Local time — what your users actually experience; useful when debugging "it happened at 3pm" reports against server logs.
• Relative time — the quickest gut-check: is this token expired, is this log entry recent, did this cron job actually run last night?

Tips for working with timestamps

• Store timestamps in UTC and convert to local time only at the display layer — never store local times without an offset.
• In JavaScript, new Date(ts) expects milliseconds; multiply unix seconds by 1000 first.
• The "year 2038 problem" affects systems storing seconds in signed 32-bit integers, which overflow on 19 January 2038. Use 64-bit integers for timestamp storage.
• When scheduling jobs across timezones, remember that cron runs in the server's timezone by default — see our cron timezone handling guide for the pitfalls.
• The date-to-timestamp section interprets your input in your local timezone, matching how a form input would behave in your app.

Common use cases

• Checking whether a JWT exp claim has passed.
• Translating created_at values from database dumps or API responses.
• Correlating log lines from different services during an incident.
• Generating test fixtures with known timestamps.
• Verifying that a scheduled job ran when it should have.

FAQ: Unix Timestamp Converter