Every CPF submission in Singapore lives or dies on one tiny detail: the NRIC check digit. Get one digit wrong, mistype one letter, or transpose two numbers, and your entire CPF EZPay upload will be rejected. The CPF Board’s system uses the check digit to verify that every NRIC and FIN on your spreadsheet is structurally valid before it accepts the submission. This article explains what the NRIC check digit is, why it matters for payroll, and how to validate NRICs in your spreadsheet without paying for specialised software. There is also a free tool at the end if you would rather skip the formula entirely. ...