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unix · iso 8601 · utc · local · live

Convert Unix timestamps to dates

Paste a Unix timestamp or ISO date and see every common representation — seconds, milliseconds, ISO 8601, UTC, local. Conversion runs locally in your browser.

Quick Start

How to convert a Unix timestamp

Auto-detects seconds, milliseconds, microseconds, or ISO 8601. Outputs every common format side by side.

  1. 01

    Paste any timestamp

    Drop a numeric timestamp — Unix seconds (10 digits, e.g. 1700000000), milliseconds (13 digits), microseconds (16), or nanoseconds (19) — or paste an ISO 8601/RFC 3339 string like 2024-01-15T14:30:00Z.

    Both Unix epochs and ISO are anchored at 1970-01-01T00:00:00 UTC. Negative integers work too — they describe pre-1970 dates and survive the conversion round-trip.

    Unix epochISO 8601RFC 3339ms vs secondsUTC
    input · Unix seconds10 digits · epoch
    1700000000
    10 chars · 1 lineepoch seconds
  2. 02

    Auto-detect unit

    The tool reads the digit count to pick the unit: 10 → seconds, 13 → milliseconds, 16 → microseconds, 19 → nanoseconds. The detected unit shows in the stats bar so you can sanity-check before reading downstream rows.

    This avoids the classic bug where a JavaScript Date.now() (ms) gets fed into a Python datetime.fromtimestamp() (seconds) and lands you in the year ~55000 AD.

    auto-detectmilliseconds vs secondsDate.now()fromtimestamp()unit safety
    detected · unitseconds · 10 digits
    10 digits → seconds
    1 unit · lockedlive
  3. 03

    Inspect formats

    Every common representation refreshes live: Unix seconds / ms / µs, ISO 8601 UTC (the safe wire format for APIs and logs), RFC 7231 UTC string, the user’s local string, and split local date / time fields.

    ISO 8601 is your safest serialisation for JSON APIs — it sorts lexicographically and never ambiguous about timezone. Use Unix ms for compact binary protocols.

    ISO 8601Unix msUTC stringlexicographic sortJSON API
    output · ISO 8601 UTC8 rows · live
    2023-11-14T22:13:20.000Z
    24 chars · UTCwire-safe
  4. 04

    Copy or download

    Copy every row as tab-separated values for a paste straight into a spreadsheet or a markdown table, or download the snapshot as a .txt file. For the inverse trip — JS Date back to Unix — see the Current Timestamp tool.

    All conversion runs in the browser via the native Date constructor; nothing is sent over the network.

    TSVspreadsheetMarkdown tableDate constructorprivacy-first
    export · clipboard8 rows · TSV
    Copied
    ready to ship0 outbound
Pro tips

Time math without DST landmines

Always store UTC

Convert to local for display only. UTC storage avoids DST jumps and timezone drift in databases.

Watch leap seconds

POSIX time doesn’t count leap seconds; some systems do. Don’t use timestamps for sub-second precision across boundaries.

Prefer Temporal eventually

The Date API has many quirks. Temporal is shipping in modern engines and handles zones correctly.

Cron is timezone-tricky

Cron expressions run in the daemon’s local zone unless told otherwise. Pin a TZ explicitly for predictable runs.

ISO 8601 sorts naturally

YYYY-MM-DDTHH:mm:ss sorts correctly as a string. Don’t use US-style MM/DD/YYYY for anything machine-readable.

Beware Y2K38

Signed 32-bit Unix timestamps overflow in 2038. Use 64-bit storage end-to-end for long-lived systems.

Related toolsTimezone ConverterISO 8601 ConverterRFC 3339 ConverterEpoch Millis to DateCurrent TimestampDate Formatter
Use Cases

When to convert timestamps

Log debugging, API payloads, database inspection.

Log debugging

Decode epoch fields from JSON logs to wall-clock time. Math runs in UTC under the hood to dodge DST jumps — local time is only for display. That means scheduling logic and date diffs survive March / November fall-back without the classic off-by-one-hour bug.

DST-safe

Database rows

Translate created_at / updated_at integers from MySQL or Postgres. Browser clock is the only source — no external time server, no privacy leak, no rate limit. Pair with NTP-synced server time for high-accuracy use cases, but for human-scale work the browser clock is plenty.

UTC-correct

API payloads

Read iat / exp / nbf from JWTs and OAuth responses. ISO 8601 output sorts naturally as strings, perfect for filenames (report-2026-01-15.pdf) and log lines that need chronological ordering without parsing. Drop into S3 keys for free time-bucketing.

ISO-sortable

Cross-language

Match Python time.time() with JS Date.now() / Java currentTimeMillis(). Pairs cleanly with cron, scheduled tasks, and timestamped log analysis. The tool's output drops directly into APScheduler, Linux cron, or GitHub Actions schedule expressions without re-formatting.

spec-grade

Schedule sanity

Verify cron output or scheduler next-run timestamps. Output respects the chosen timezone offset (Z vs +05:30) so REST APIs and database TIMESTAMP WITH TIME ZONE columns round-trip cleanly. No ambiguity between "noon UTC" and "noon local".

zone-aware

Cache TTLs

Confirm Redis EXPIREAT and CDN cache-control values. Confirms the difference between epoch seconds (10 digits) and milliseconds (13 digits) before you commit code that mis-multiplies by 1000 — a classic bug in cross-language time handling.

epoch-accurate
FAQ

Frequently asked questions

We auto-detect: 10 digits = seconds, 13 = milliseconds, 16 = microseconds, 19 = nanoseconds. Negative values (pre-1970) work too.
Unix v1 used a 32-bit signed int starting January 1, 1970 UTC. The choice was arbitrary but stuck — it's the universal epoch now.
32-bit signed seconds overflow on 2038-01-19. Modern systems use 64-bit ints (good for 292 billion years). Check that your DB column is BIGINT.
Sub-second precision is preserved in ms / µs paths. Seconds-only inputs lose fractional precision.
No. Conversion runs locally in your browser.
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