Date-Time Format Converter
Auto-detect a date-time string (ISO 8601/9075, RFC 3339/7231, Unix or millisecond timestamp, Mongo ObjectID, Excel serial, UTC string) and convert it into every other format at once. Timezone-less input is read and shown in UTC.
Input
The format is auto-detected. Input without a timezone is treated as UTC.
Output
| Format | Value |
|---|---|
| No data yet | |
Guides
Paste any date or timestamp and instantly see it in every common format. The Date-Time Format Converter auto-detects what you give it — an ISO string, a Unix timestamp, a Mongo ObjectID, an Excel serial number — and converts it into all the others at once, so you never have to remember conversion formulas or juggle timezone math.
What it does
Enter a single date-time string and the tool figures out its format, then lays out the equivalent value in ten representations side by side:
- JS locale date string — the standard JavaScript
Datestring form - ISO 8601 and ISO 9075 — the SQL/database date-time formats
- RFC 3339 — the internet timestamp standard used in APIs and logs
- RFC 7231 — the HTTP header date format (
Mon, 22 Jul 2024 15:00:00 GMT) - Unix timestamp (seconds) and Timestamp (milliseconds)
- UTC format — the
toUTCStringform - Mongo ObjectID — a 24-character hex ID whose leading bytes encode the time
- Excel date/time — the serial number spreadsheets use
How to use it
Type or paste a value into the input box, for example 2024-07-22 15:00:00, 1700000000, or 5f9a1c2b3d4e5f6a7b8c9d0e. The results table updates as you type. Use the copy button to grab the whole table, or download it as a CSV. Click "Try an example" to load a sample value and see the output shape.
Because a plain date without an offset is ambiguous, the converter reads timezone-less input as UTC and reports every output in UTC. Include an explicit offset — 2024-07-22T15:00:00+02:00 — and it is normalized to UTC for you.
FAQ
Which input formats are supported?
ISO 8601, ISO 9075, RFC 3339, RFC 7231 / HTTP dates, UTC strings, Unix timestamps (seconds), millisecond timestamps, Mongo ObjectIDs, and Excel serial dates. Date-only values like 2024-07-22 are accepted and treated as midnight UTC.
How does it tell a Unix timestamp from an Excel serial?
Both can look like plain numbers, so the tool uses digit length: 1–10 digits are read as Unix seconds, 11–13 digits as millisecond timestamps, and numbers containing a decimal point as Excel serial dates.
Why is my local time different from what I see?
The converter works entirely in UTC to stay deterministic and reproducible. If your source value has no timezone marker, add one (like +02:00 or Z) and the tool will convert it correctly.
What is a Mongo ObjectID doing here?
The first 4 bytes of a MongoDB ObjectID are a Unix timestamp, so an ObjectID carries a creation time. The tool reads that time and shows the ObjectID whose timestamp matches your input (the remaining bytes are zeroed).
Privacy
This tool runs entirely in your browser. Your date-time string is parsed and formatted locally and never leaves your device or gets sent to a server.
Use it from code
From 3 credits per callREST API
curl -X POST https://api.iotools.cloud/v1/tool/date-time-format-converter \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"dateTimeString": "2024-07-22 15:00:00"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `date-time-format-converter` tool (Date-Time Format Converter) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.