Epoch / Unix Timestamp Converter

How to Use This Epoch Converter

Paste a Unix timestamp and the tool converts it to a human-readable date instantly — no button click needed. It auto-detects whether your timestamp is in seconds or milliseconds. Switch to Date → Epoch mode with the toggle or Ctrl+Enter to go the other way.

The live clock at the top shows the current Unix timestamp ticking in real time. Click it to paste into the input field.

Why Developers Need an Epoch Converter

We built this because every debugging session at 3 AM eventually hits a wall of raw epoch numbers — and the human brain was not designed to read 1711641600 at a glance. API responses, database records, JWT expiration claims, CI/CD pipeline outputs, they all store time as seconds since January 1, 1970 UTC, and when a production incident is burning you need to parse those numbers fast, not do mental division by 86400 to figure out which day it was.

The timezone part is what actually burns people. A deployment fails, the logs show 1711641600 — is that your local midnight or UTC midnight? We kept running into this ourselves with cron jobs, cache TTLs, and certificate expiration checks, so we made the tool show both local and UTC simultaneously. No more guessing which timezone the server was thinking in.

Seconds vs Milliseconds — The Bug That Gets Everyone

We see this mistake more than almost any other in cross-platform code: someone passes a seconds-based epoch into a function expecting milliseconds, and the date comes back as January 1970. Or the reverse — a milliseconds value read as seconds points to the year 56000. Backend systems (PostgreSQL, MySQL, Python time.time()) use 10-digit seconds. JavaScript Date.now() and Java System.currentTimeMillis() use 13-digit milliseconds. This tool auto-detects which one you pasted so the conversion is correct either way.

The Year 2038 Problem

The Linux kernel merged Y2038 fixes starting in version 5.6, released March 2020, because 32-bit systems store Unix time as a signed integer that tops out at 2,147,483,647 — January 19, 2038 at 03:14:07 UTC. One second later the counter wraps negative and reads as December 1901. Modern 64-bit systems handle this fine, but the embedded devices running ATMs, medical equipment, and industrial controllers — millions of them still on 32-bit time — will not get kernel updates. The devices shipping right now with 32-bit epoch counters will still be running in 2038.

Epoch in Different Languages

Python time.time() returns seconds as a float. JavaScript Date.now() returns milliseconds.

Go time.Now().Unix() gives seconds. Java has both: Instant.now().getEpochSecond() for seconds and System.currentTimeMillis() for ms.

Ruby Time.now.to_i — seconds. PHP time() — seconds, microtime(true) — seconds with microsecond float.

The pattern: backend defaults to seconds, browser defaults to milliseconds.

Common Epoch Values

0 — Jan 1, 1970 UTC. The epoch itself. Default when a timestamp field is unset.

946684800 — Jan 1, 2000. The Y2K boundary.

1000000000 — Sep 9, 2001. The "billennium" when epoch hit 10 digits.

2147483647 — Jan 19, 2038. 32-bit overflow.

-1 — Dec 31, 1969 23:59:59 UTC. Catches bugs in systems that reject negative timestamps.

Epoch in Databases

PostgreSQL stores timestamps internally as microseconds since 2000, not 1970 — that is why EXTRACT(EPOCH FROM ts) exists.

MySQL UNIX_TIMESTAMP() returns seconds since 1970. SQLite has no timestamp type — you pick INTEGER or TEXT.

MongoDB BSON Date uses milliseconds. Redis TTL uses seconds. The inconsistency across databases is the reason developers convert epochs constantly.

JWT Tokens and Epoch

We hit a JWT debugging issue that turned out to be embarrassingly simple — the exp claim was set with Date.now() (milliseconds) instead of dividing by 1000, so the token expired in the year 56000 instead of in one hour. RFC 7519 defines iat, exp, and nbf as NumericDate values — always seconds, never milliseconds. When an auth flow breaks, paste the exp value here and compare it to the live clock above to see if the token is already expired.

Why Client-Side Matters

Timestamps from production incident logs and JWT tokens from user sessions contain operational context you probably do not want leaving your network. This tool runs entirely in your browser — no server calls, no data stored. Open DevTools Network tab to verify.

Keyboard Shortcuts

Auto-converts as you type — no submit button needed. Press Ctrl+Enter to toggle between Epoch → Date and Date → Epoch mode. Press Ctrl+Shift+C to copy the primary result to your clipboard.

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