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UUID / GUID Generator — Universal Unique ID
Generate cryptographically secure UUIDs / GUIDs (v4) instantly — universally unique identifiers in bulk, 4 formats, free.
✓ Free✓ No Login✓ UUID v4✓ Bulk Generate✓ 4 Formats✓ Download TXT
5
150
1 UUID Generated
166c61abb-7155-460c-bc60-edfff2359239
📚 UUID Structure
550e8400-e29b-41d4-a716-446655440000
Time low (8 hex)
Time mid (4 hex)
Version + time (4 hex)
Variant + clock (4 hex)
Node / random (12 hex)
⚡ Common Uses
→Database primary keys
→Session & auth tokens
→API request IDs
→File & asset naming
→Distributed system IDs
→Transaction references
UUID Versions Explained
There are five UUID versions (v1–v5), each using a different algorithm. v4 is by far the most common for web and software applications.
📖 How to Use the UUID Generator
1
Set the Quantity
Use the slider to choose how many UUIDs to generate at once — from 1 to 50.
2
Choose a Format
Pick Standard, UPPERCASE, No Hyphens or With Braces depending on what your code or database requires.
3
Generate & Export
Click Generate. Copy individual UUIDs, Copy All as a newline-separated list, or Download TXT for database seeding scripts.
❓ Frequently Asked Questions
What is the difference between a UUID and a GUID?+
None in practice — GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit standard; UUID (Universally Unique Identifier) is the RFC 4122 term. Every UUID this tool generates is a valid GUID — use the braces output format for Microsoft-style {xxxxxxxx-...} values.
How many bytes is a UUID (and how long is it)?+
A UUID is 128 bits = 16 bytes of data, written as a 36-character string: 32 hexadecimal characters plus 4 hyphens. Version 4 contains 122 random bits, which allows about 5.3 x 10^36 possible values — enough that collisions are effectively impossible.
What is a UUID?+
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal characters separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. It is designed to be unique across all space and time without a central authority.
What is the difference between UUID v1 and v4?+
UUID v1 is based on the current timestamp and the MAC address of the machine generating it. UUID v4 is randomly generated. v4 is recommended for most applications as it does not leak system information like MAC address or creation time.
Are UUIDs truly unique?+
UUID v4 uses 122 bits of randomness, giving 2^122 possible values (~5.3 × 10^36). The probability of generating two identical UUIDs is astronomically small — effectively zero for any practical use case.
What are UUIDs used for?+
UUIDs are used as primary keys in databases, session tokens, transaction IDs, file names, API request IDs, and anywhere a unique identifier is needed without coordination between systems.
Is it safe to use UUIDs as public-facing IDs?+
UUID v4 is safe to expose publicly as it reveals no information about your system. However, they are guessable in theory (given enough attempts), so for security-sensitive tokens consider using a cryptographic random string instead.