PAYG Withholding Calculator
Enter gross pay, frequency, and tax scale. The calculator returns weekly equivalent, tax withheld, and net pay using the ATO Statement of Formulas (NAT 1004). HELP/HECS, leave loading, and tax offsets are not modelled.
How PAYG withholding works
For each pay period, convert to a weekly equivalent, look up the matching coefficient bracket for the employee's tax scale, apply y = a × x − b, then convert back to the pay period.
The ATO publishes coefficient tables for six tax scales: 1 (no tax-free threshold), 2 (tax-free threshold claimed, most employees), 3 (foreign resident), 4 (no TFN, flat 47%), 5 (full Medicare exemption), 6 (half Medicare exemption).
For weekly pays, take whole dollars in gross pay and add 99 cents to get your x. For fortnightly: divide by 2. Monthly: × 3 ÷ 13. Quarterly: ÷ 13.