Base64 to UUID
Decode URL-safe Base64 UUID values back into standard 36-character RFC 4122 UUIDs. Great for reversing compact IDs.
Base64 to UUID
Powered byJavaScript & RFC 4122
All decoding happens locally in your browser. Nothing is sent to any server.
Paste Base64 UUIDs and click Decode to see standard UUIDs.
What is a Base64 UUID?
A Base64 UUID is a compact URL-safe representation of a 16-byte UUID (128 bits). It usually appears as a 22-character string (without padding), and this tool converts it back into the standard 36-character RFC 4122 UUID format.
URL-safe format
This tool supports URL-safe Base64, where "+" becomes "-", "/" becomes "_", and padding is optional.
Validates length
The input must decode to exactly 16 bytes; otherwise the tool reports an invalid line.
Supports multiple values
Paste multiple Base64 UUIDs (one per line) and decode them all in one click.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value standardized by the IETF in RFC 4122. It’s typically represented as a 36-character string with hyphens.
Base64 provides a shorter representation of those 16 bytes, which this tool converts back into the canonical UUID string.
- 16 bytes = 128 bits
- Standard UUID string is 36 characters
- Base64 represents the same bytes in 22 characters (without padding)
- Base64 UUIDs are URL-safe when using the "-" and "_" variant
UUID Format
32 bits
16 bits
16 bits
16 bits
48 bits
This tool converts the 16 raw bytes represented by Base64 back into the canonical UUID string.
UUID Versions Compared
Any UUID version can be encoded in Base64, since they all use the same 128-bit size.
| Version | Generation Method | Use Case | Requires |
|---|---|---|---|
| v1 | Timestamp + MAC address | Time-ordered logging | Network interface |
| v2 | DCE security (UID/GID) | Legacy DCE systems | System identity |
| v3 | MD5 hash of namespace+name | Deterministic IDs | Namespace + name |
| v4 | Random | General purpose — UUID v4 Generator → | None |
| v5 | SHA-1 hash of namespace+name | Deterministic IDs (secure) | Namespace + name |
| v6 | Reordered timestamp (RFC 9562) | Sortable time-based IDs | Clock + node |
| v7 | Unix timestamp + random (RFC 9562) | Database-friendly sortable IDs | None |
Example Base64 UUIDs
Click an example to decode it into a standard UUID.
How This Base64 → UUID Tool Works
The tool validates that the input is a URL-safe Base64 string representing 16 bytes. It then decodes those 16 bytes and formats them as a standard UUID string (8-4-4-4-12).
Conversion happens entirely in your browser; nothing is sent to our servers.
Common Use Cases
Use this tool when you need to:
Frequently Asked Questions
Quick answers about Base64 → UUID decoding.
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