Generate universally unique identifiers (UUID/GUID) instantly. Create version 4 random UUIDs in bulk with customizable formatting options.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems.
Version 4 UUIDs are randomly generated and have 2122 possible combinations, making collisions extremely unlikely.
UUID Version
Count (1-100)
Format Options
Generated UUIDs
Click Generate to create UUIDs
🛈Privacy Note: All UUIDs are generated locally in your browser using the Web Crypto API for cryptographically secure random values. No data is sent to any server.
What the UUID Generator Does and Why It Matters
The UUID Generator creates universally unique identifiers (also called GUIDs) on demand, with a choice of version and formatting and the option to generate many at once. A UUID is a 128-bit value designed to be unique without any central coordinating authority.
They are everywhere in software: primary keys, request IDs, idempotency keys, file names, and event identifiers. Generating them here is quick and local, which is convenient when you need a handful of valid identifiers for testing or seed data without writing code.
How to Use UUID Generator
Choose the UUID version you need (version 4 random is the common default).
Pick a format option such as lowercase, uppercase, or with/without hyphens if offered.
Set how many identifiers to generate for bulk output.
Click Generate to produce the values.
Copy a single UUID or the whole batch to your clipboard.
Regenerate as many times as you need fresh values.
Supported Inputs and Limitations
What you control
UUID version selection
Formatting options (case, hyphenation)
The number of identifiers to generate at once
What you get
One or many valid UUID strings
Copy-ready output for code, tests, or records
Consistent formatting across the batch
Known limitations
Version 4 uniqueness is practical rather than absolute, though the odds of a collision are astronomically small.
A UUID is an identifier, not a secret; do not use one as a security token or password.
Different versions encode different things (time, randomness); pick the one your system expects.
Privacy and Security
UUIDs are generated locally in your browser using its secure random source, so no values are sent to or stored by NovaTools. You can generate identifiers freely without any network activity, which keeps test data and internal IDs on your own machine.
Frequently Asked Questions
Which UUID version should I choose?
Version 4 (random) is the right default for most applications. Choose a time-based version only when your system specifically needs ordering or a timestamp embedded in the identifier.
Can two generated UUIDs ever collide?
In practice, no. A version 4 UUID has 122 random bits, so the probability of generating a duplicate is so small it is safe to ignore for ordinary use.
Is a UUID secure enough to use as a token?
Not by itself. UUIDs are meant to be unique, not unguessable in a security sense. For access tokens or secrets, use a generator designed for cryptographic randomness and treat the value confidentially.
Generate RFC 4122 compliant version 4 UUIDs (Universally Unique Identifiers) instantly. UUIDs are 128-bit identifiers that are virtually guaranteed to be unique across all systems. They're widely used in databases, APIs, distributed systems, and anywhere a unique identifier is needed.
How to Use
Set the Count (1-100) to generate multiple UUIDs at once.
Choose format options: UPPERCASE or Remove hyphens.
Click Generate UUID(s) to create your identifiers.
Click the copy icon next to any UUID to copy it individually.
Use Copy All to copy all generated UUIDs to your clipboard.
Use Download TXT to save UUIDs as a text file.
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. It's represented as 32 hexadecimal digits displayed in five groups separated by hyphens (8-4-4-4-12 format). UUIDs are designed to have an extremely low probability of collision.
What is UUID version 4?
Version 4 UUIDs are randomly generated. They contain 122 random bits (6 bits are fixed to indicate version and variant), providing 2122 possible combinations. This means the chance of generating the same UUID twice is astronomically small - effectively zero for practical purposes.
When should I use UUIDs?
UUIDs are ideal when you need unique identifiers without a central authority to coordinate ID allocation. Common use cases include: database primary keys, API resource identifiers, session tokens, file names, message IDs in distributed systems, and transaction IDs.
Are UUIDs secure for tokens?
UUIDv4 provides 122 bits of randomness, which is suitable for many token use cases. However, for high-security applications like session tokens or authentication codes, you may want to use additional security measures or consider dedicated token generation libraries.
Can UUIDs collide?
Theoretically yes, but practically no. With 2122 possible UUIDv4 values, you would need to generate about 1 billion UUIDs per second for 100 years to have a 50% chance of a single collision. For all practical purposes, UUIDs can be considered unique.
