UUID Decoder
Decode UUID versions and variants online.
Loading tool...
What is UUID Decoder?
The UUID Decoder breaks any RFC 4122 identifier into its meaningful parts: the version nibble, the variant bits, and — for time-based versions — the exact moment the ID was generated. Paste a single UUID or thousands at once, and get a table with creation dates, clock sequences, and node addresses, all computed offline in your browser.
Key Benefits
- Recover creation dates of database records, API objects, and log entries from v1/v6/v7 UUIDs
- Instantly identify how a UUID was generated: random, time-based, hash-based, or custom
- Flexible input accepts braced, urn-prefixed, unhyphenated, and mixed-case forms
- Batch decoding with per-row copy buttons and CSV export for audits and debugging
- Field-level breakdown shows clock sequences and node MAC addresses for v1 UUIDs
Common Use Cases
- •Dating database rows or API resources whose only identifier is a UUID
- •Auditing distributed systems to see when and where time-based UUIDs were minted
- •Spotting malformed or suspicious UUIDs during security reviews
- •Converting batches of UUIDs from logs into sortable timestamps for analysis
How to Use the UUID Decoder
- Paste your UUIDs: Paste one or more UUIDs into the input box, one per line. Braces, urn:uuid: prefixes, missing hyphens, and mixed-case hex are normalized automatically.
- Choose a timezone: Pick the display timezone from the dropdown. Decoded timestamps are shown in local form plus UTC ISO 8601.
- Read the results: Each row shows the detected version, variant, and — for v1, v6, and v7 — the creation date. Invalid lines are flagged in red. The field-level breakdown card explains the first valid UUID bit by bit.
- Copy or export: Copy individual rows, copy the whole table, or download everything as a CSV with version, variant, timestamp, and UTC columns.
Key Features
- Identifies every RFC 4122 version (v1-v8) plus nil and max UUID edge cases
- Extracts exact creation timestamps from time-based v1, v6, and v7 UUIDs
- Reports the variant: NCS, RFC 4122, Microsoft, or reserved legacy formats
- Accepts hyphenated, plain-hex, braced, uppercase, and urn:uuid: inputs
- Batch decode unlimited UUIDs with per-row copy buttons and CSV export
- 100% client-side — UUIDs never leave your browser
Frequently Asked Questions
What information is stored inside a UUID?
It depends on the version. Random v4 UUIDs contain no meaningful data beyond randomness. Time-based v1 and v6 encode the creation time in 100-nanosecond intervals since 1582 plus a clock sequence and node ID, while v7 stores Unix epoch milliseconds directly. Hash-based v3 and v5 encode a namespace and name instead. This decoder reads those bit fields and converts timestamps back to human-readable dates.
Which UUID versions can be traced back to a creation date?
Versions v1, v6, and v7 are time-based and can be decoded to an exact timestamp. If your UUID starts with a 1, 6, or 7 in the third group (the version nibble), this tool can recover its creation date. Versions 3, 4, 5, and 8 have no extractable timestamp.
What is the difference between version and variant?
The version (first hex digit of the third group) tells you how the UUID was generated — random, time-based, or hash-based. The variant (top bits of the fourth group) tells you which specification family it follows: NCS (legacy), RFC 4122 (standard), Microsoft (legacy), or reserved. Most modern UUIDs are variant RFC 4122.
Is any data uploaded when I decode UUIDs?
No. All parsing happens locally in your browser using plain bit operations on BigInt values. UUIDs never leave your machine, there are no rate limits, and the tool works completely offline.