The terms EC-No and EC# refer to the seven-digit code (sometimes called the EC number) that has been allocated by the Commission of the European Communities for commercially available chemical substances within the European Union. The European EC Number should not be confused with the Enzyme Commission EC number for enzymes.
The "EC#" designation supersedes the outmoded EINECS and ELINCS designations, and the EC# codes include those on the so-called No-longer Polymers List, a list of substances that were on the European market between 18 September 1981 and 31 October 1993 and at the time were regarded as polymers, but are no longer regarded as such.
The EC# is made up of seven digits according to the pattern xxx-xxx-x.
EINECs numbers start with number 200-001-8.
ELINCS numbers start with 400-010-9
Numbers in the No-longer Polymers List start with 500-001-0.
The EC/EINECS/ELINCS Number may be written in a general form as:
in which R is the check digit and N represents a fundamental sequential number. The check digit is the remainder of the following sum after division by 11:
N1 + 2×N2 + 3×N3 + 4×N4 + 5×N5 + 6×N6