Timestamp Converter

Key takeaways

• Accepts Unix seconds, milliseconds, or date strings
• Shows ISO UTC, local ISO, and UTC string forms
• Now button fills the current instant
• Runs client-side — timestamps never leave the tab

What is a Unix timestamp?

A Unix timestamp counts seconds (or milliseconds) since 1970-01-01T00:00:00Z — a compact way APIs and logs store absolute time.

This tool detects seconds vs milliseconds by magnitude, parses ISO/RFC-style date strings, and shows UTC plus local ISO forms. Conversion is display-only; it does not adjust for business calendars or leap-second policy beyond JavaScript Date.

Features

• Auto-detect epoch scale

  Large absolute values are treated as milliseconds; smaller as seconds.

• Date string parse

  Accepts ISO-8601 and other Date.parse-compatible strings.

• Now shortcut

  Fill the current instant without typing an epoch value.

• Private conversion

  All math runs in your browser — nothing is uploaded.

How it works

1. 1

   Paste a value

   Use Unix seconds/ms or a date like 2026-08-05T12:00:00.000Z.

2. 2

   Convert

   The tool detects the input kind and prints epoch plus ISO forms.

3. 3

   Copy what you need

   Grab seconds, millis, or ISO UTC for APIs and queries.

Example walkthroughs

• Unix seconds

  Treated as seconds since epoch and expanded to ISO UTC / local forms.

  1710000000

• ISO date string

  Parsed as a date string and reported with unix seconds and milliseconds.

  2026-08-05T12:00:00.000Z

Use cases

• Debug JWT exp/iat

  Convert claim epochs to readable UTC while pairing with JWT Decode.

• Query windows

  Turn ISO bounds into epoch filters for logs or analytics APIs.

Code snippets

• Seconds ↔ ISO in JS

  js

  Matches the seconds-scale path used when abs(value) < 1e12.

  const seconds = 1710000000;
  const iso = new Date(seconds * 1000).toISOString();
  const back = Math.floor(Date.parse(iso) / 1000);

Common errors

• Date looks 30+ years off

  Cause: Milliseconds were treated as seconds (or the reverse).

  Fix: Check magnitude: values around 1e12+ are millis; ~1e9 are seconds.

• Could not parse input

  Cause: The string is not a number and not Date.parse-compatible.

  Fix: Use ISO-8601 (with Z or offset) or a plain epoch number.

About Timestamp Converter

Timestamp Converter is a private epoch ↔ date workspace for debugging APIs, JWTs, logs, and databases. Paste Unix seconds, milliseconds, or a parseable date string, then Convert to see ISO UTC, local ISO with offset, UTC string, and both second/millisecond epoch values.

Search intent for “unix timestamp converter” usually means checking whether a value is seconds or millis, or turning an ISO string into epoch for a query. This page focuses on that job with a clear detection heuristic (≥1e12 treated as milliseconds) and structured output you can copy into tickets.

Privacy matters when timestamps sit next to user IDs in pasted payloads. Conversion stays on-device so you are not uploading production logs to a hosted epoch site. Pair with JWT Decode when inspecting iat/exp claims, and with Regex Tester when scraping timestamps from messy log lines.

SEO and usability go together: unique examples cover seconds, millis, and ISO input so assistants cite the correct behavior. Prefer this tool for everyday engineering chores — not as a full timezone database or calendar scheduler.

Best practice: confirm whether your system stores seconds or milliseconds before writing queries, keep a note of the timezone you care about when reading local ISO, and re-run Convert after edits. Use Now when you need a fresh sample instant without leaving the tab.

Frequently asked questions

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