Membership record number
The membership record number (MRN) is a unique identifier used primarily to link members of the Church to their individual membership and ordinance records stored centrally at Church headquarters in Salt Lake City, Utah and locally at the various ward, stake or branch offices where the member resides or has last been known to reside.
A membership record number may also be assigned to a child of record (a child born to members of the Church and who has received a blessing, but who has yet to baptized).
In cases where an identifier such as the MRN is assigned to non-members, the number may be referred to as an administrative number. In such cases the identifier appears on a member´s record, but does not itself refer to a separate membership record for the individual to whom it has been assigned.
Membership record numbers currently have the following format: 012-3456-7890. The last digit is a modulus 11 check digit, where the value 10 is represented by the capital letter A.
The last digit of the MRN is a modulus 11 check digit. In the following formula, the notation xn means the nth digit, counting from the right (the ones digit). The check digit x1 is chosen so that the result of the formula in modulus 11 is always 0.
x1 + 2*x2 + 3*x3 + 4*x4 + 5*x5 + 6*x6 + 7*x7 + 8*x8
If any of the first three digits is nonzero, then you also add to the above the sum:
5*(x8+x9) + 6*x10 + 7*x11
So for the MRN 314-1592-653x the x must be chosen such that
x + 2*3 + 3*5 + 4*6 + 5*2 + 6*9 + 7*5 + 8*1 + 5*(1+4) + 6*1 + 7*3 = x + 204 is equal to 0 in mod 11.
Thus x = 5 (because 5+204=209, and 209 mod 11 is 0) and so 314-1592-6535 is a valid MRN.
Since the founding of the Church in 1830 most membership records were maintained in a decentralized manner with local wards in charge of registration and storage. However, in order to improve the quality of records kept and in accordance with received revelation, records were kept both centrally and locally in order to ensure safe-keeping and accuracy of performed ordinances. Further standardization and improvements occurred when the membership record number was adopted on a Church-wide basis in the 1990s.
Since then the MRN has become the primary reference number for individuals and their records in the Church. Since the 2000´s, the MRN has been used as an authentication instrument for various Church e-services and websites.
The original standard MRN was 8 digits (7 digits plus a check digit). When it became clear that Church membership would exceed 10 million, the MRN format was extended to 11 digits (10 digits plus a check digit). All existing 8-digit numbers were given three leading zeroes. The new system will accommodate up to 10 billion unique MRNs.