GUID Generator – Generate GUID Online (Free Tool)
Free online GUID Generator tool to generate GUIDs for Windows and .NET applications. Create Globally Unique Identifiers in standard format with hyphens or braces. Generate multiple GUIDs at once for database testing. All generation happens locally in your browser.
Example Output
Five random v4 GUIDs (UUIDs) generated locally using crypto.randomUUID() — globally unique with vanishingly small collision probability.
a3f8d2c1-9e7b-4f5a-8c1d-2b3e4f5a6c7d 4e9c8b2a-5d1f-4e8b-9c3a-1f2d3e4b5c6a ...
What is GUID Generator?
Generate GUIDs (a.k.a. UUIDs) in your browser — v4 random (default) or v1 timestamp-based. The v4 generator uses `crypto.randomUUID()` for true cryptographic randomness, with collision probability so small that 1 billion GUIDs per second for 100 years still has near-zero collision risk.
Why use this tool?
- Touch-friendly UI, fine on phones for on-the-go edits
- No registration, account, or installation required
- No API keys to manage and no rate limits to monitor
- Built for developer workflows: copy-friendly output, syntax-aware highlighting where useful
- Works with very large inputs (multi-megabyte JSON, long regex patterns, big tables)
How to use
- Choose UUID version (v4 random or v1 timestamp)
- Set the count (1-1000+)
- Click Generate — copy individual or all as JSON/CSV
- Toggle case (upper/lower) and braces format
Examples
Primary-key seed
Generate 50 GUIDs for primary keys in a SQL Server table where IDs must be globally unique across servers.
Microsoft-style braces
Toggle braces on for `{a3f8d2c1-…}` format used in Windows registry and .NET configs.
Idempotency keys
Generate a single GUID to use as an idempotency key for a Stripe / payment API call.
Common use cases
- Database primary keys (SQL Server, .NET, Azure)
- Idempotency keys for API requests
- Distributed-system unique identifiers
- Test fixture IDs
- Registry / config-file unique tokens
Troubleshooting
- Need exact UUID format with specific case
- Use the case toggle (default lowercase). Some systems (.NET, COM) prefer uppercase; toggle on if needed.
- Bulk-generated GUIDs include duplicates
- Vanishingly unlikely with v4 (1 in 2^122). If you see duplicates, the generator is broken; the browser's native `crypto.randomUUID()` does not produce dupes in practice.
- v1 includes the MAC address
- Modern v1 generators (including this one) use random node IDs, not the real MAC — so you don't leak hardware fingerprints.
Frequently Asked Questions
GUID (Globally Unique Identifier) is a 128-bit integer used in Windows and .NET for unique identification. It is essentially the same as UUID but often formatted differently with hyphens and braces.
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