Methodology
Last updated: May 2026
How We Calculate
Each SumZA calculator uses formulas verified against official South African government sources. Below are the methodologies for our key calculators.
Tax & Salary Calculators
Our PAYE/Salary calculator uses the SARS tax brackets for the 2025/2026 tax year (1 March 2025 to 28 February 2026). We include:
- Primary rebate (R17,235)
- Additional rebate for persons 65+ (R9,444)
- Additional rebate for persons 75+ (R3,145)
- UIF at 1% of gross salary (capped at R181,728 per year)
- Tax threshold: R95,750 (under 65), R149,549 (65-74), R166,338 (75+)
Property Calculators
Bond repayments use the standard annuity formula: P = rPV / (1 – (1+r)^-n), where P is monthly payment, r is monthly interest rate, PV is loan amount, and n is number of months. Transfer duty follows the 2026 SARS brackets.
VAT Calculations
VAT is calculated at the current South African rate of 15% (as of 1 April 2018). Our calculator supports both adding VAT (VAT-inclusive) and removing VAT (VAT-exclusive) calculations.
UIF Calculations
UIF contributions are calculated at 1% of gross monthly salary for employees, with an equal contribution from employers, capped at the annual ceiling.
Overtime Calculations
Overtime rates follow the BCEA: normal overtime at 1.5x, Sunday work at 2x, and public holiday work at 2x the regular hourly rate.