UUID Generator

Generate standard Version 1, 4, or 5 Universally Unique Identifiers (UUIDs) in bulk.

Generator Settings

v4 is the standard cryptographically secure random UUID.

Max 5000

Generated UUIDs

fact_check Reviewed by Senior Editor
verified Reviewed: Jul 28, 2026
update Updated: Jul 28, 2026
commit v2.0.0
schedule 5 min read

lightbulb When to use this tool

  • check_circle Generating a unique primary key before inserting a new record into a database that uses UUIDs as identifiers.
  • check_circle Creating test fixture data that needs unique identifiers — user IDs, order IDs, session tokens — for unit tests or integration test setups.
  • check_circle Generating a unique name for an uploaded file to prevent filename collisions in a storage bucket.
  • check_circle Creating a unique correlation ID to trace a request through a distributed system's logs.
  • check_circle Generating multiple UUIDs at once for seeding a database with test data.

Why use our tool?

Cryptographically Random — Uses crypto.randomUUID()

Bulk Generation — 1 to 100 UUIDs at Once

Standard and Compact Format

One-Click Copy for Single or All

Zero Server Dependency

How it works

1

Set the quantity of UUIDs to generate (default: 1, max: 100).

2

Select the output format: standard hyphenated (RFC 4122) or compact no-hyphen.

3

Click 'Generate UUID(s)' — the output appears immediately.

4

Click 'Copy' next to any individual UUID, or 'Copy All' to copy the entire batch.

5

Click 'Generate' again to produce a fresh set — each generation produces entirely new, independent identifiers.

Examples

science Single UUID for Database Record

science Bulk UUID Generation for Test Fixtures

Frequently Asked Questions

What is the probability of generating a duplicate UUID? expand_more
Effectively zero in any practical scenario. UUID v4 has 122 bits of randomness (the remaining 6 bits are fixed version/variant markers). The probability of a collision when generating n UUIDs is approximately n²/(2^123). To have even a 50% chance of a collision, you would need to generate approximately 2.71 × 10^18 (2.71 quintillion) UUIDs. At a rate of one billion UUIDs per second, this would take about 86 years. For all practical database, application, and distributed system uses, UUID collisions can be treated as impossible.
What is the difference between UUID v4 and other UUID versions? expand_more
UUID v1 is generated from the current timestamp and the network interface's MAC address — making it time-ordered and potentially traceable to the generating machine. UUID v3 is deterministically generated by hashing a namespace and name with MD5. UUID v4 is entirely randomly generated — the most widely used for general-purpose unique identifiers. UUID v5 is like v3 but uses SHA-1 instead of MD5. UUID v7 (2024 RFC) is a newer format that combines a millisecond timestamp with random bits, providing both uniqueness and time-based ordering — useful for database indexing. For most use cases, v4 is the correct choice.
What is the difference between UUID and GUID? expand_more
GUID (Globally Unique Identifier) is Microsoft's term for the same concept as UUID (Universally Unique Identifier). They use the same 128-bit format and the same RFC 4122 specification. The terms are interchangeable in practice — GUIDs are UUIDs by a different name. Microsoft's SQL Server, .NET, and COM systems use the term GUID; most other environments (databases, web APIs, programming languages) use UUID.
Should I use UUIDs or sequential integer IDs in my database? expand_more
Each has trade-offs. Sequential integer IDs are compact, index-efficiently, are human-readable, and have predictable ordering. Their main weaknesses: expose record counts (user ID 47 reveals you have around 47 users), are guessable in sequential APIs (/user/47, /user/48), and require a central authority to assign (the database sequence). UUID v4 identifiers are unpredictable, work in distributed systems without central coordination, don't expose record counts, and allow client-side ID generation before insertion. Their weaknesses: larger (16 bytes vs 4-8 bytes), random UUIDs fragment B-tree indexes causing performance issues at scale (UUID v7 solves this with time-ordering). For most web applications, UUIDs are the better default. For high-write-throughput systems, UUID v7 or time-sortable alternatives are preferred.
Can I use UUIDs as file names for uploaded files? expand_more
Yes — this is a common and recommended pattern. When users upload files, storing them under their original filenames causes collision risks (two users uploading 'profile.jpg' would overwrite each other) and security risks (path traversal attacks using crafted filenames). The standard approach is to generate a UUID at upload time and store the file as {uuid}.{extension} — e.g. 7b5e8e40-2a3d-4f6b-9c1d-8e7f3a2b0c5d.jpg. The original filename is stored in the database. This is the pattern used by most cloud storage integrations (AWS S3, Google Cloud Storage, Azure Blob).

More Developer & Security