--- title: "UUID Generator: Free Online Tool with Guide & FAQs | ShoutingNow" description: Generate RFC 4122 UUIDs and Microsoft-style GUIDs in your browser. Switch between Version 1 (time-based), Version 4 (random), Version 7 (time-ordered), nil. url: "https://shoutingnow.com/tools/uuid-generator/" image: "https://shoutingnow.com/wp-content/uploads/2026/07/UUID-generator-and-benefits-overview-1024x683.webp" --- # UUID Generator Generate RFC 4122 UUIDs and Microsoft-style GUIDs without leaving your browser. Switch between Version 1 (time-based), Version 4 (random), Version 7 (time-ordered), nil, and braced GUID formats, one at a time or in a bulk batch of up to 500, with copy and download built in. Want a full walkthrough of UUID versions, database patterns, and the mistakes people usually make? Our [UUID Generator guide](https://shoutingnow.com/blog/uuid-generator-and-benefits-overview/) pairs with this [free UUID Generator tool](https://shoutingnow.com/tools/uuid-generator/) and covers v1, v4, v7, nil, and GUID use cases. ## What this tool does A **UUID** (Universally Unique Identifier) is a 128-bit value written out as 32 hexadecimal digits split into five groups: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Developers reach for UUIDs as database primary keys, correlation IDs in logs, opaque public URLs, and session tokens, mainly because they stay unique without needing a central allocator to hand them out. Our generator runs entirely in your browser using crypto.getRandomValues(), and crypto.randomUUID() where the browser supports it. Nothing gets sent to a ShoutingNow server. ## UUID versions supported Tab Standard Best for Version 1 RFC 4122, timestamp + random node Legacy systems that expect time-ordered v1 IDs; generally prefer v7 for new work. Version 4 RFC 4122, random Default choice for primary keys, API IDs, and session tokens. Version 7 RFC 9562, Unix ms + random Sortable, time-ordered IDs for distributed databases (PostgreSQL, Cassandra). Nil/Empty RFC 4122, all zeros Placeholder meaning “no UUID assigned”, not a real identifier. GUID Same bits as UUID, braced uppercase Windows, .NET, COM, and registry tooling that expects {XXXXXXXX-...}. ## How to generate UUIDs 1. Pick a version tab: Version 4 is selected by default. 2. Click Generate: a new UUID appears in the results panel with a one-click Copy button. 3. Bulk mode: enter how many you need (1 to 500), click Generate, then Copy all or Download to a file. 4. Switch versions: each tab keeps its own bulk count; results refresh when you generate again. ## UUID format breakdown Every standard UUID is 128 bits displayed as 36 characters including hyphens: - 8 hex digits: time_low (v1/v7) or random (v4) - 4 hex digits: time_mid or random - 4 hex digits: version nibble + remaining bits - 4 hex digits: variant field + clock/random - 12 hex digits: node (v1) or random (v4/v7) The version number appears in the third group (e.g. 4 for v4, 7 for v7). The variant bits in the fourth group mark the value as RFC-compliant. ## Common UUID versions (reference) Version Method Notes v1 Timestamp + MAC/random node Sortable by time; may leak hardware hints in older implementations. v3 Name-based (MD5) Deterministic from namespace + name, not offered here; use when reproducibility is required. v4 Random Recommended for most new applications. v5 Name-based (SHA-1) Deterministic like v3 with stronger hash, generate in code when needed. v7 Unix timestamp + random Modern time-sortable alternative to v1. ## Where UUIDs are used - Database primary keys: avoid auto-increment collisions when merging shards. - Public API resource IDs: opaque, non-sequential URLs. - Order and transaction IDs: unique across services without coordination. - Log correlation: trace a request across microservices. - File and object storage keys: S3-style paths with no central counter. ## Privacy and disclaimer UUIDs from this tool get generated locally using your browser’s secure random source, and ShoutingNow never stores the values it produces. They come as-is with no warranty of uniqueness, so always enforce a uniqueness constraint in your own database. The nil UUID, worth noting, is a fixed constant rather than a generated value. ## Learn more Read our step-by-step guide: [UUID Generator Guide](https://shoutingnow.com/blog/uuid-generator-and-benefits-overview/). ## Related tools - URL Encode & Decode - Sitemap Link Counter - QR Code Generator - Password Strength Checker - Character Counter - Browse all tools ## Frequently Asked Questions ### What is a UUID? It is a 128-bit identifier written as 32 hexadecimal characters split into five hyphen-separated groups. It stays unique across systems without needing a central registry, which makes it a natural fit for database keys and distributed IDs. ### Which UUID version should I use? **Version 4** works as the default for most apps, fully random and simple. Reach for **Version 7** when you need IDs that sort by creation time in an index, and only use **Version 1** when a legacy system specifically requires it. **GUID** gives you the Microsoft-style braced uppercase format. ### How many UUIDs can I generate at once? Bulk mode handles up to **500** per click, with results listed one per line, so use Copy all or Download to a file to grab them. ### Are these UUIDs RFC 4122 compliant? Version 1, 4, and nil outputs follow the RFC 4122 field layout with correct version and variant bits. Version 7 follows RFC 9562, and GUIDs simply wrap a Version 4 UUID in braces with uppercase hex. ### Is the UUID generator free? It is, generate as many single or bulk UUIDs as you need with no signup required, since everything processes right in your browser. ### Where can I learn more about UUID use cases? Check our [UUID Generator guide](https://shoutingnow.com/blog/uuid-generator-and-benefits-overview/) for version comparisons, database examples, formulas, common mistakes, and a link back to the [free generator](https://shoutingnow.com/tools/uuid-generator/). ```json [{"@context":"https://schema.org","@type":"Organization","name":"ShoutingNow","url":"https://shoutingnow.com/","logo":{"@type":"ImageObject","url":"https://shoutingnow.com/wp-content/themes/shoutingnow-theme/assets/images/logo.png"},"sameAs":["https://x.com/makani20","https://www.linkedin.com/in/makani20/","https://post-see.com"],"contactPoint":{"@type":"ContactPoint","contactType":"customer support","email":"support@shoutingnow.com","url":"https://shoutingnow.com/contact/"},"slogan":"Learn. Build. Grow."},{"@context":"https://schema.org","@type":"WebPage","name":"UUID Generator","description":"Generate RFC 4122 UUIDs and Microsoft-style GUIDs in your browser. 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