Developer Utility

UUID v1/v4 Compare Generator

Generate UUID v1 and UUID v4 at the same time and compare the differences between time-based and random-based UUIDs.

Generate UUID v1 Create example UUID v1 values and examine the characteristics of time-based UUID structures.

Generate UUID v4 Generate multiple random-based UUIDs commonly used in modern software development.

Version Comparison Compare generation methods, recommended use cases, and considerations for UUID v1 and UUID v4.

Generation Count 5

Generation Mode v1 + v4

v1 Results 0

v4 Results 0

UUID Generation Settings

Choose the number of UUIDs to generate and the UUID version. UUID v4 is the most common choice for general development.

Selection Guide

Choose v1 when generation order or time sequence matters. Choose v4 when you need general-purpose unique IDs, filenames, or test data.

Generation Count

Generate between 1 and 100 UUIDs.

Generation Mode

Compare v1 + v4 Generate both versions side by side. Generate UUID v1 Only Generate time-based UUID examples. Generate UUID v4 Only Generate random-based UUIDs.

UUID v1 Results

UUID format generated using timestamp information.

Ready

UUID v1 results will appear here.

UUID v4 Results

UUID format generated from random values.

Ready

UUID v4 results will appear here.

UUID v1 / v4 Comparison

Quickly review the differences between both UUID versions.

Category	UUID v1	UUID v4
Generation Method	Time-based	Random-based
Characteristics	Generation order and timing can be partially inferred	Highly random and widely used as a general identifier
Recommended Usage	Testing internal identifiers where time sequence matters	User IDs, filenames, API test IDs, and general identifiers
Considerations	Time-related information may be exposed depending on implementation	Does not include chronological ordering information

Help

What is the UUID v1/v4 Compare Generator?

This developer utility generates UUID v1 and UUID v4 values and helps compare their generation methods and practical differences. It can be useful for sample database keys, filenames, test data, and temporary identifiers.

Features

Generate UUID v1 format
Generate UUID v4 format
Generate and compare both versions simultaneously
Generate up to 100 UUIDs at once
Copy individual results or all results
Download results as TXT

Difference Between UUID v1 and UUID v4

UUID v1 is time-based and may reveal generation order or timing. UUID v4 is random-based and is the most widely used version in web development and identifier generation.

Important Notes

UUIDs generated by this tool are created within your browser. For security-sensitive purposes such as authentication tokens, API secrets, or cryptographic keys, use dedicated secure generation methods instead.

Which UUID version should I use?

Unless you specifically need time-based ordering, UUID v4 is generally recommended because it is random-based and widely supported.

Are UUIDs guaranteed to be unique?

UUIDs are designed to make collisions extremely unlikely. While no method guarantees a mathematically perfect zero-collision rate, UUIDs are generally considered sufficiently unique for practical applications.