Free tool

MPAN validator + DNO lookup

Paste a supply number to verify its check digit, read off the distributor id, and resolve the responsible DNO. Add the site postcode and the tool cross-checks the two — flagging the wrong-DNO mismatch that quietly stalls applications. Runs entirely in your browser.

MPAN (13-digit core or 21-digit supply number)Site postcode

The S-number

The bill “supply number” is 21 digits. The 8-digit top line carries the profile, meter time-switch and line-loss classes; the 13-digit core holds the two-digit distributor id, a unique identifier, and a check digit. The distributor id is what ties the meter to its DNO.

Valid checksumdistributor id 21

Supply number018011452101234567895

Distributor id21

DNO from MPANNational Grid Electricity Distribution

Licence areaSouth Wales

DNO from postcodeNational Grid Electricity Distribution

MPAN and postcode agree on National Grid Electricity Distribution.