Epoch Converter
Convert epoch time (seconds or milliseconds since 1970) to dates and back. Built for JavaScript Date.now() values — free, no sign-up.
Epoch time, explained
Epoch time is the number of time units since 1970-01-01 00:00:00 UTC — the Unix epoch. It is the same concept as a Unix timestamp; "epoch" is just the term data engineers and JavaScript developers tend to reach for. One number, no timezones, no formatting arguments: that is why systems from embedded devices to cloud APIs store time this way.
Epoch seconds vs. epoch milliseconds
The unit is everything. Traditional Unix systems count seconds (10 digits: 1700000000), while JavaScript, Java, and most modern APIs count milliseconds (13 digits: 1700000000000) — that is what Date.now() returns in your browser console right now. Feed a 13-digit value to something expecting seconds and you land in the year 56,000. This converter auto-detects the unit by digit count, so pasting a Date.now() value just works.
Converting dates to epoch
Going the other direction is just as common: turn "2024-06-01 00:00 UTC" into epoch seconds for a database query, or into millis for a JavaScript comparison. Paste any reliably parseable date — YYYY-MM-DD, YYYY-MM-DD HH:MM, full ISO 8601 — and you get epoch seconds, epoch milliseconds, ISO, UTC, and local time in one view.
Edge cases worth knowing
Fractional seconds are accepted. Pre-1970 dates produce negative values and convert fine. Values beyond about ±8.64×10¹⁵ milliseconds exceed what a double-precision float can represent exactly and are rejected rather than silently mangled — if you hit that, your input is almost certainly in the wrong unit.
Private by design
Epoch values usually come from logs, tokens, and production systems. Conversion is 100% local: nothing you paste ever leaves your browser tab.
Frequently asked questions
Is "epoch time" the same as a "Unix timestamp"?
Yes. "Epoch time" and "Unix timestamp" both mean time elapsed since 1970-01-01 00:00:00 UTC. "Epoch millis" specifically means the millisecond variant that JavaScript and Java use.
Why does JavaScript use milliseconds?
JavaScript's Date works in milliseconds (Date.now() returns 13 digits), while classic Unix timestamps are seconds (10 digits). This converter auto-detects which one you pasted.
How do I convert the other way?
Switch to date-to-timestamp mode and paste any parseable date (YYYY-MM-DD, ISO 8601). You get both epoch seconds and epoch milliseconds back.
What about dates before 1970?
They become negative epoch values and convert correctly within the representable range.
Is my data uploaded?
No. All conversion happens locally in your browser.
Related tools
- Timestamp converter — Convert Unix timestamps to readable dates and back. Handles seconds and milliseconds, UTC and local time.
- Unix Timestamp Converter — Convert Unix timestamps to readable dates and back. Auto-detects seconds vs. milliseconds, shows UTC and local time — free, no sign-up.
- Timestamp to Date Converter — Convert a Unix timestamp into a human-readable date and time — shown in UTC and your local timezone. Paste a seconds or milliseconds value and read…
- Milliseconds to Date Converter — Convert a millisecond timestamp — the 13-digit kind JavaScript's Date.now() returns — into a readable date and time, in UTC and your local timezone.…
- JSON formatter, Base64 & URL codec — Format valid JSON and encode or decode UTF-8 Base64 and URL components in your browser.
- JSON workbench — editor, viewer & validator — Edit JSON on the left and inspect it live on the right: validate with exact line-and-column errors, format, explore a collapsible tree, run JSONPath queries and convert to CSV, XML or YAML.
- Password generator — Create strong, random passwords with cryptographic randomness. Everything runs in your browser; nothing is uploaded or stored.
- QR code generator — Turn text or URLs into QR codes with selectable size and error correction. Download as PNG or SVG, all locally.
- Word counter — Count characters, words, lines and paragraphs, and estimate reading time. Paste text or load a .txt file.
- UUID generator — Generate bulk UUID v4 identifiers with cryptographic randomness. Copy the list or download it as text.