UUID Version 1 Generator (Time-Based)
Create UUID version 1 identifiers, which embed a precise timestamp and traditionally a network card address. This tool generates time-ordered UUIDs, useful for scenarios where sortable, time-based unique identifiers are required.
UUID v1 Generator
Generate time-based UUID version 1
How to use
Enter your data in the input field, click Convert, and the result will appear in the output field. You can then copy or download the result.
How it works
Generate UUID version 1 identifiers that embed the current timestamp and a unique node identifier. UUID v1 creates time-ordered unique IDs suitable for database keys and event tracking.
The generator combines a 60-bit timestamp (100-nanosecond intervals since October 15, 1582), a 14-bit clock sequence, and a 48-bit node ID to create globally unique identifiers.
Example generated UUIDs:
Generated UUID v1: 6ba7b810-9dad-11d1-80b4-00c04fd430c8 Structure breakdown: 6ba7b810 - Time low (32 bits) 9dad - Time mid (16 bits) 11d1 - Time high + version (16 bits, version=1) 80b4 - Clock sequence + variant (16 bits) 00c04fd430c8 - Node ID (48 bits) Key property: UUIDs generated later have higher values.
Each generated UUID is unique even when created in rapid succession. The clock sequence increments to prevent collisions when multiple UUIDs are generated within the same timestamp tick.
When You'd Actually Use This
Database primary keys
UUID v1 as primary keys are roughly time-ordered, improving index performance compared to random UUIDs. Inserts go to the end of the index, reducing page splits.
Event sourcing and audit logs
Events need unique IDs that preserve order. UUID v1's embedded timestamp means sorting by ID approximates sorting by time. Useful for replay and debugging.
Distributed system coordination
Multiple services generate UUIDs without coordination. The combination of timestamp and node ID ensures uniqueness across the entire distributed system.
Session and transaction tracking
Generate unique session IDs that encode creation time. Debugging becomes easier when you can see approximately when a session was created from its ID.
File naming for uploads
User uploads need unique filenames. UUID v1 prevents collisions and groups files by upload time when sorted alphabetically. Better than sequential numbers for distributed storage.
Message queue correlation
Track messages through a pipeline with UUID v1 correlation IDs. The time component helps identify bottlenecks and understand message flow timing.
What to Know Before Using
UUID v1 reveals generation time.Anyone with a UUID v1 can extract approximately when it was created. This is a feature for auditing but a privacy concern for user-facing identifiers.
Node ID may expose machine identity.Original UUID v1 used MAC addresses as node IDs. Modern implementations often use random node IDs to prevent tracking which machine generated a UUID.
Clock sequence handles time rollback.If the system clock is set backward, the clock sequence changes to maintain uniqueness. This prevents duplicate UUIDs during NTP adjustments or daylight saving transitions.
UUID v1 is not cryptographically secure.Don't use UUID v1 as security tokens or passwords. The predictable structure makes it unsuitable for authentication or authorization purposes.
Pro tip: For public-facing identifiers where you don't want to reveal creation time, use UUID v4 (random) instead. Reserve UUID v1 for internal system IDs.
Common Questions
What's the difference between UUID v1 and v4?
UUID v1 is time-based with embedded timestamp and node ID. UUID v4 is completely random. v1 is time-ordered (better for databases), v4 is unpredictable (better for security).
Can UUID v1 collisions occur?
Extremely unlikely. The combination of timestamp, clock sequence, and node ID provides 122 bits of uniqueness. You'd need to generate billions per second for years to have any risk.
How do I generate UUID v1 in code?
Most languages have libraries: Python (uuid.uuid1()), Node.js (uuid.v1()), Java (UUID.nameUUIDFromBytes for v3/v5, third-party for v1). Use established libraries, don't roll your own.
Is UUID v1 still recommended?
For internal system IDs where time-ordering helps, yes. For public identifiers or security-sensitive uses, prefer UUID v4. Many modern systems use v4 or ULID for better privacy.
What happens if two machines have the same node ID?
Collisions could occur if they generate UUIDs at the same timestamp. This is why proper implementations use unique node IDs (MAC address or random) for each generating instance.
Can I sort UUIDs v1 by time?
Yes, UUID v1 is lexicographically sortable by time. Later-generated UUIDs have higher values. This makes them efficient for database indexes and time-range queries.
What's the timestamp resolution?
100-nanosecond intervals (10 million per second). The timestamp is a 60-bit counter. This provides fine granularity and won't overflow for thousands of years.
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