UUID v1 Generator
Generate v1 UUIDs in bulk with timestamp, clock sequence and node decoded live — entirely on this device.
Decoded fields
- Timestamp
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- 100-ns ticks
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- Clock sequence
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- Node
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Press ? for shortcuts
Do it offline:$ npx uuid v1
How to use it
- Press Regenerate for a batch of 1 to 100,000 v1 values; large runs move to a worker.
- Check the strip: timestamp, clock sequence and node decoded from the batch's first UUID.
- Download or copy in whichever notation your codebase wants, braces and URN included.
UUID v1 packs a 60-bit Gregorian timestamp, a 14-bit clock sequence and a 48-bit node into every value. This page generates batches up to 100,000 and decodes those three fields beneath the output — including whether the node is a random stand-in, which here it always is.
How it works
The 60-bit count of 100-nanosecond ticks since 1582-10-15 is stored low-first: 32 bits, then 16, then 12 beside the version nibble. A 14-bit clock sequence guards against rollbacks; the node fills the final 48 bits.
No MAC address is read here: the generator draws one random node per session and sets its multicast bit — the RFC 9562 marker that discloses the substitution honestly.
Examples
f81d4fae-7dec-11d0-a765-00a0c91e6bf6timestamp = 1997-02-03T17:43:12.216Z
clock sequence = 10085
node = 00:a0:c9:1e:6b:f6RFC 4122's classic example, decoded: a real 1997 network card — its multicast bit is clear, so the node is hardware.
5ca76000-8820-11f1-ab0d-0f1e2d3c4b5atimestamp = 2026-07-25T12:00:00.000Z
clock sequence = 11021
node = 0f:1e:2d:3c:4b:5a (random — multicast bit set)The shape this page produces: an odd first node octet marks 48 random bits standing where a MAC would sit.
Every example on this page is executed against the same engine that powers the tool, on every build.
Gotchas worth knowing
Milliseconds are a truncation
v1 time has 100-nanosecond resolution; the decoded ISO instant floors it to milliseconds, and the strip keeps the raw tick count alongside.
Common errors
100,000 is the browser-side cap — need more? script it: `npx uuid v1`- Above the cap, a loop in a terminal beats a browser tab; your settings stay untouched.
Count must be a whole number between 1 and 100,000.- Reachable only through restored or hand-edited state; the visible input refuses fractions and text.
FAQ
Does generating v1 UUIDs leak my MAC address?
Not here: the library never touches hardware identifiers. It substitutes 48 random bits with the multicast bit set — decode any value above and the strip labels it.
Should new systems use v1 or v7?
v7, almost always: its timestamp leads so values sort naturally, with no node field to explain. v1 remains for schemas and peers that already speak it.
What does the clock sequence do?
It is a 14-bit guard that changes when the clock moves backwards or the node changes, keeping identifiers unique across restarts and clock adjustments.