Check Digit

The check digit is a clever mathematical safeguard built into every MPAN. It's calculated using a specific formula applied to the preceding digits. When you enter an MPAN into a system, it recalculates this digit - if it doesn't match, you've made a typo somewhere.

This might seem like a small detail, but in an industry where incorrect meter numbers can lead to bills going to the wrong customer or consumption being misallocated, it's an important line of defence. The calculation uses a series of prime numbers as multipliers, making it highly effective at catching common errors like transposed digits.

How it works: The check digit validates the "MPAN Core" - the last 13 digits of the full MPAN. Each of the first 12 digits is multiplied by a prime number weight: [3, 5, 7, 13, 17, 19, 23, 29, 31, 37, 41, 43]. The products are summed, and the formula (sum % 11) % 10 produces the check digit.

For most users, you don't need to understand the maths - just know that if a system rejects your MPAN, double-check you've entered all the digits correctly.