UUID v6 is a time-ordered UUID version based on RFC 9562. It stores a 60-bit timestamp in the most-significant bits by reordering the fields used in v1, then sets the version nibble to 6 and the variant bits to the RFC 4122 standard.

Is UUID v6 deterministic?

Yes. UUID v6 values are deterministic for a given system clock and node/sequence. Two generators with identical clocks and nodes produce identical UUIDs, and later times produce lexicographically larger values.

How does UUID v6 differ from UUID v1?

UUID v6 uses the same time+clock sequence+node components as v1, but it rearranges the timestamp bits so that the most significant bits represent the time. This makes v6 UUIDs sort correctly when compared as strings, unlike v1.

Can I decode the timestamp from a UUID v6?

Yes. The initial 60 bits represent a 100‑nanosecond interval count since October 15, 1582. Reverse the field reordering to recover the original timestamp.

Is UUID v6 secure for tokens or passwords?

No. Like v1, UUID v6 embeds predictable timing information and a node identifier. It should never be used for secrets or anything requiring unpredictability. Use a random identifier such as UUID v4 for those scenarios.

What is the structure of a UUID v6?

A UUID v6 has the pattern xxxxxxxx-xxxx-6xxx-yxxx-xxxxxxxxxxxx. The first three groups encode the reordered timestamp, the 13th character is '6', and the remaining bits carry clock sequence/variant and node.

Free · Client-side · RFC 9562 · Time-Ordered

UUID v6 Generator

Generate time-ordered UUID v6 identifiers instantly. Encodes a reordered timestamp for lexicographic sorting (RFC 9562) — entirely in your browser.

Part of WebEasier's UUID Generator suite — the most complete UUID toolkit on the web.

UUID v6 Generator

Timestamp + Random Node · crypto.getRandomValues()

All UUIDs generated locally in your browser. Node field uses a cryptographically random 48-bit value (not a real MAC address).

Quantity

Version

v6 (time-ordered)

Your UUID v6 values will appear here.
Set a quantity and click Generate.

What is a UUID v6?

A UUID v6 (version 6) is a time-ordered UUID defined by RFC 9562. It stores a 60-bit timestamp in the most-significant bits by reordering fields from v1, then adds a version=6 nibble and standard variant. The 13th character is always '6'.

1f11dfca-ee58-ec06-baed-123456789abc

Version Bit

13th char = '6'
xxxxxxxx-xxxx-6xxx-yxxx-…

Timestamp

60-bit
100ns intervals since
15 Oct 1582

Node Field

48-bit
MAC address or random (this tool uses random)

Standard

RFC 4122
IETF specification

Overview

What is a UUID v6?

UUID version 6 is the modern time-ordered UUID format from draft RFC 9562. It takes the same components as UUID v1 (timestamp, clock sequence, and node) but rearranges the timestamp bits so that lexicographic sorting of the entire identifier matches chronological order.

Because the most‑significant bits are the timestamp, UUID v6 works well with B-tree indexes, time-series databases, and any system that benefits from naturally sortable keys.

Like v1, v6 includes a 48‑bit node field (this tool uses a random value to protect privacy) and a 14‑bit clock sequence. It is not suitable for secret tokens.

For fully random identifiers, see our UUID v4 Generator; for deterministic name-based IDs, use UUID v5.

UUID v6 Format

1f11dfca-ee58-6c06-baed-123456789abc

1f11dfca timestamp high
32 bits

ee58 timestamp mid
16 bits

6c06 timestamp low+ver
16 bits

baed clock seq & variant
16 bits

123456789abc node
48 bits

The 13th character is always 6 for version 6.
The 17th character contains the RFC 4122 variant bits.

Security Note

UUID v6 is deterministic and embeds time information. Do not use it for secrets, passwords, or tokens. Use a cryptographically random identifier instead.

Structure

UUID v6 Field Anatomy

Every UUID v6 is composed of five fields; the first three hold a reordered timestamp.

xxxxxxxx time_high

xxxx time_mid

6xxx time_low + ver

yxxx clock_seq

xxxxxxxxxxxx node

Field	Bits	Description	Fixed value?
`time_high`	32	Highest 32 bits of the reordered timestamp	No — changes per generation
`time_mid`	16	Middle 16 bits of the reordered timestamp	No — changes per generation
`time_low_and_version`	16	Lowest 12 bits of timestamp plus version nibble `0110`	Version nibble always `6`
`clock_seq_and_reserved`	16	14-bit clock sequence + 2 variant bits (`10`) per RFC 4122	Variant bits always `10`
`node`	48	Random 48-bit value (multicast bit set) for privacy	Regenerated each batch

Decoded Timestamp of Last Generated UUID v6

Generate a UUID above to decode its timestamp →

Live Examples

Example UUID v6 Values Generated Now

Fresh UUID v6 examples generated client-side on page load. Click any to copy.

How It Works

How UUID v6 Generation Works

UUID v6 generation follows RFC 9562. The algorithm captures the current time as a 60-bit integer counting 100-nanosecond intervals since October 15, 1582, then rearranges the timestamp bits so the most significant bits sort chronologically and inserts the version 6 nibble.

Because JavaScript's Date.now() has only millisecond resolution, this tool adds a sub-millisecond counter to simulate the finer granularity required by the spec, preventing duplicate timestamps within the same millisecond.

Get current time in 100ns intervals since 15 Oct 1582
Split into time_low, time_mid, time_hi
Set bits 12–15 of time_hi to 0001 (version 1)
Generate cryptographically random 14-bit clock sequence
Set variant bits to 10 (RFC 4122)
Generate random 48-bit node (multicast bit set to 1)
Format as xxxxxxxx-xxxx-1xxx-yxxx-xxxxxxxxxxxx

When to Use UUID v6

UUID v6 is the modern time-ordered version optimized for lexicographic sorting. Use it whenever time-ordering matters:

Audit logs & event sourcing Cassandra time-series keys Append-only B-tree writes Distributed tracing IDs Time-stamped records Sequential event queues Message broker IDs Monitoring systems Enterprise legacy systems Legal audit trails

When NOT to Use UUID v6

Do not use UUID v6 for session tokens, CSRF tokens, API keys, or any security credential. The predictable timestamp component reduces the search space, making brute-force attacks feasible. Use UUID v4 for security-sensitive identifiers.

Comparison

UUID v6 vs Other UUID Versions

Understand when to choose UUID v6 over other versions.

Version	Generation Method	Sortable?	Private?	Best For
v1	Timestamp + MAC/random node	By timestamp	No (reveals time)	Time-ordered logging, Cassandra
v2	DCE Security (POSIX UID/GID)	Partial	No	Legacy DCE systems
v3	MD5 hash of namespace+name	No	Deterministic	Name-based IDs (MD5)
v4	Fully random (122 bits)	No	Yes	General purpose — use our UUID v4 tool
v5	SHA-1 hash of namespace+name	No	Deterministic	Name-based IDs (SHA-1)
v6	Reordered timestamp (RFC 9562)	Lexicographically	No	Sortable replacement for v1
v7	Unix ms timestamp + random (RFC 9562)	Lexicographically	Partial	Modern database-friendly sortable IDs

For most new projects, UUID v7 is the recommended sortable alternative to v6. For random/anonymous IDs, choose UUID v4. See the complete UUID versions guide on our main UUID Generator page.

FAQ

Frequently Asked Questions

Everything you need to know about UUID v6 and this generator.

A UUID v6 is a time-ordered UUID defined by RFC 9562. It encodes a reordered 60-bit timestamp (100‑nanosecond intervals since October 15, 1582), a 14-bit clock sequence, and a 48-bit node identifier. The 13th character is always '6', indicating version 6.

UUID v4 is entirely random (122 bits of entropy) and reveals nothing about when or where it was created. UUID v6 encodes a reordered timestamp and node identifier, making values lexicographically sortable but not private. Use v4 for security tokens; use v6 (or the improved v7) for time-ordered records. See our UUID v4 Generator for a direct comparison.

Yes. Reverse the v6 reordering by extracting the high, mid and low timestamp fields from the first three bytes, masking off the version nibble. Combine them into a 60‑bit value, subtract the Gregorian offset (122,192,928,000,000,000 100ns intervals) and divide by 10,000 to get Unix milliseconds. The decoded time appears automatically below in the "UUID v6 Field Anatomy" section.

No. UUID v6 is NOT suitable as a session token, CSRF token, or API key. The timestamp component makes it partially predictable — knowing one UUID v6 narrows the search space for nearby ones. For security-sensitive identifiers, always use UUID v4 or a dedicated cryptographic random token generator.

No. Web browsers do not expose MAC addresses. This tool generates a cryptographically random 48-bit node value for every batch, with the multicast bit (bit 0 of the first octet) set to 1 to signal it is not a real hardware address — exactly as RFC 4122 recommends for environments without MAC access. No identifying information about your device is ever used.

UUID v6 is well-suited for time-ordered logging, audit trails, Apache Cassandra primary keys (where the TIMEUUID type previously used v1), distributed tracing, and any scenario where knowing the generation order of identifiers matters. Its lexicographically ordered timestamp fields reduce index fragmentation in append-heavy B-tree databases.

For new projects requiring sortable time-based UUIDs, UUID v7 (RFC 9562) is the modern recommendation. It uses a Unix millisecond timestamp in the most-significant bits, making it lexicographically sortable (v6 already sorts correctly, but v7 is preferable for new systems). UUID v7 also pairs better with modern databases. UUID v6 remains appropriate for compatibility with older v1 systems and when a 100‑ns timestamp is required.

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UUID v6 Generator

UUID v6 Generator

What is a UUID v6?

UUID v6 Format

UUID v6 Field Anatomy

Example UUID v6 Values Generated Now

How UUID v6 Generation Works

When to Use UUID v6

UUID v6 vs Other UUID Versions

Frequently Asked Questions

What is a UUID v6?

How is UUID v6 different from UUID v4?

Can I extract the timestamp from a UUID v6?

Is UUID v6 secure for session tokens?

Does this tool use my real MAC address?

When should I use UUID v6?

Should I use UUID v6 or UUID v7 for new projects?

Complete UUID Tools Directory

UUID Generation

UUID Validation

UUID Parsing

UUID Formatting

UUID Conversion

Developer UUID Generators

Alternative ID Generators

25+ UUID & ID Tools

Explore All Free Developer Tools