UUID Bluetooth Utility

BLE UUID Converter

Convert Bluetooth Low Energy UUIDs between 16-bit, 32-bit and 128-bit Bluetooth Base UUID representations. Detect Bluetooth SIG base UUIDs and convert standard 128-bit UUIDs to the little-endian byte order commonly seen inside BLE advertising and GATT protocol data.

✓ 16-bit UUID ✓ 32-bit UUID ✓ 128-bit UUID ✓ Bluetooth Base UUID ✓ BLE Byte Order

BLE

UUID Conversion

● Ready

Conversion Mode Auto mode detects 16-bit, 32-bit or standard 128-bit UUID input.

128-bit Packet Byte Output BLE protocol fields often serialize 128-bit UUIDs least-significant octet first.

Bluetooth UUID / Hex Bytes Examples: 180D, 0000180D, 0000180D-0000-1000-8000-00805F9B34FB, or 16 little-endian packet bytes.

Bluetooth Base UUID: 00000000-0000-1000-8000-00805F9B34FB. A Bluetooth SIG 16-bit Assigned Number replaces the low 16 bits of the first 32-bit field, while a 32-bit Assigned Number replaces the complete first 32-bit field.

BLE UUID Conversion Result Converted

128-Bit Bluetooth UUID —

Detected Format —

16-Bit UUID —

32-Bit UUID —

128-Bit UUID —

Bluetooth Base Match —

Assigned Number Decimal —

Standard UUID Bytes —

BLE Packet Bytes —

Conversion Breakdown

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What Is a BLE UUID Converter?

A BLE UUID Converter converts Bluetooth service, characteristic and descriptor identifiers between compact 16-bit or 32-bit Assigned Numbers and their full 128-bit UUID representations.

The tool also handles byte-order conversion for 128-bit UUID values captured inside Bluetooth Low Energy advertising data, GATT data or other protocol structures.

Bluetooth Base UUID

Bluetooth defines a common base UUID used to expand Bluetooth SIG Assigned Numbers:

00000000-0000-1000-8000-00805F9B34FB

A 16-bit or 32-bit Bluetooth Assigned Number is inserted into the first 32-bit field.

Convert 16-Bit BLE UUID to 128 Bits

For a 16-bit UUID, pad the value to eight hexadecimal digits and insert it into the Bluetooth Base UUID.

16-bit UUID:
0x180D

32-bit expanded field:
0000180D

128-bit UUID:
0000180D-0000-1000-8000-00805F9B34FB

Convert a 32-Bit Bluetooth UUID

32-bit UUID:
12345678

Bluetooth Base UUID:
12345678-0000-1000-8000-00805F9B34FB

A 32-bit value can only be shortened further to a 16-bit Assigned Number when its upper sixteen bits are zero.

Convert 128-Bit UUID to 16 Bits

A 128-bit UUID can be represented by a Bluetooth 16-bit Assigned Number only when it matches the Bluetooth Base UUID pattern and the upper sixteen bits of the first field are zero.

0000180D-0000-1000-8000-00805F9B34FB

Base portion matches:
0000xxxx-0000-1000-8000-00805F9B34FB

Assigned Number:
0x180D

Bluetooth UUID Byte Order

A human-readable UUID is normally shown most-significant byte first. Bluetooth protocol data that contains a 128-bit UUID commonly carries the UUID value least-significant octet first.

Standard UUID:

0000180D-0000-1000-8000-00805F9B34FB

Standard byte sequence:

00 00 18 0D 00 00 10 00
80 00 00 80 5F 9B 34 FB

BLE little-endian packet bytes:

FB 34 9B 5F 80 00 00 80
00 10 00 00 0D 18 00 00

16-Bit UUID Byte Order in Advertising Data

A 16-bit service UUID inside BLE Advertising Data is also stored little-endian.

Service UUID:
0x180D

Advertising Data bytes:
0D 18

Therefore raw packet bytes 0D 18 represent UUID 0x180D, not 0x0D18.

Common BLE UUID Examples

Short UUID	Expanded 128-bit UUID
180D	0000180D-0000-1000-8000-00805F9B34FB
180F	0000180F-0000-1000-8000-00805F9B34FB
2A37	00002A37-0000-1000-8000-00805F9B34FB
2902	00002902-0000-1000-8000-00805F9B34FB

Custom 128-Bit BLE UUIDs

Manufacturers and application developers can also use custom 128-bit UUIDs that do not derive from the Bluetooth Base UUID.

12345678-1234-5678-9ABC-DEF012345678

Such a UUID cannot be shortened to a Bluetooth SIG 16-bit or 32-bit Assigned Number simply by removing fields. The complete 128-bit UUID identifies it.

BLE UUID Converter FAQs

What is the Bluetooth Base UUID?

It is 00000000-0000-1000-8000-00805F9B34FB and is used to expand Bluetooth SIG 16-bit and 32-bit Assigned Numbers.

How do I convert UUID 180D to 128 bits?

Pad it to 0000180D and insert it into the first field of the Bluetooth Base UUID, producing 0000180D-0000-1000-8000-00805F9B34FB.

Can every 128-bit UUID be converted to 16 bits?

No. Only UUIDs matching the Bluetooth Base UUID and containing a valid 16-bit value in the short-UUID position can be represented that way.

Can every Bluetooth Base UUID be converted to 32 bits?

Yes, when the final 96 bits match the Bluetooth Base UUID, the first 32 bits form its compact 32-bit value.

Why are BLE UUID bytes reversed in packet captures?

Bluetooth protocol fields commonly serialize UUID values least-significant octet first, while UUID strings are normally displayed in standard most-significant-byte-first notation.

What do bytes 0D 18 mean in BLE advertising?

As a 16-bit UUID encoded little-endian, they represent UUID 0x180D.

What is a custom BLE UUID?

It is a complete 128-bit UUID that does not necessarily derive from a Bluetooth SIG Assigned Number or the Bluetooth Base UUID.

Does this tool identify the service name?

The converter focuses on UUID representation and byte order rather than depending on a potentially changing Assigned Numbers name database.

Convert BLE UUID Formats

Expand Bluetooth short UUIDs, analyze 128-bit UUIDs and convert standard Bluetooth UUID strings to or from the little-endian byte order used in BLE protocol data.