Register Address Converter
Convert Modbus register addresses between the request offset (0-based), 1-based sequence number and 5/6-digit reference addresses.
Address conversion
Converted addresses appear here...
Reference table
Common address examples...
How to use the register address converter
Choose the data area
Select the data area first: holding registers (4xxxx), input registers (3xxxx), coils (0xxxx) or discrete inputs (1xxxx). The tool uses that area's reference prefix to interpret the input.
Enter an address
You can type any of these forms and the tool converts between all of them:
- Request address (0-based protocol offset, range 0–65535), e.g.
0 - Sequence number (1-based), e.g.
1 - 5-digit reference, e.g. holding register
40001 - 6-digit reference, e.g.
400001
Examples
Holding register 40001 is request address 0; 400001 also means request address 0. Click Examples to load a sample.
Protocol note: Reference addresses such as 40001 are a common datasheet convention, not a guarantee that a device supports that exact address. Always confirm with the device manual before sending. Function 03/04 register requests use the 0-based protocol address.