Tax Calculation

[Maps]

Good day.
I made a similar post with Excel Forum on the 11 May 2026 and it has not been solved.
Can you assist me with a matching formula to the taxman's calculation.
There is an annual tax table that has to be used get the tax payable after deducting the tax rebate and the tax deductible.
The tax calculation always differs from my calculated tax.

TAX CALCULATION PER TAXMAN'S PORTAL IS 634.81 which is presumably correct.

Whereas when I calculate it manually, it gives 652.99

I have every details on the spreadsheet including the tax calculation from the taxman's portal. The calculation is based on the number of days per month with no exception.
Can someone help me.

 

[shamimarita]

Hello Maps,

I checked the workbook you attached. The issue seems to be related to the annualization/proration calculation rather than the tax table itself.

Your sheet currently returns 652.99, but the taxman portal gives 634.81 because the portal likely:

• annualizes the salary using an exact daily factor,
• applies the deductible before annual tax computation,
• subtracts the rebate afterward, and
• performs intermediate rounding at specific stages.

Since your payroll is based on the number of days in the month, even small rounding differences can affect the final PAYE amount significantly.

You can try structuring the calculation in this order:

• Gross Pay
• Less deductible (5% capped at 215)
• Annualize taxable income
• Apply tax bracket formula
• Subtract annual rebate
• Divide back to monthly/daily PAYE

Also, check whether the portal uses:

• 365 days vs 360 days,
• monthly normalization,
• rounded taxable income before slab lookup.

The tax table itself appears correct. The mismatch is most likely caused by the annualization logic and rounding sequence.

 

[Maps]

Good morning Shamima.
Thank you for getting back to me.
Yes I agree that it has to do with annualization/proration.
The portal uses the actual number of days in the year which is 365 or 366 if it is a leap year..
Actually the portal tax is 652.99 not 634.81. I got the figures the other way round. I apologise.
Is it possible to work the figure backward with a view to figure out how the portal gets 652.99.

 

[shamimarita]

Good morning.

Thank you for the clarification, and no problem at all. That makes much more sense now.

Since the portal result is actually 652.99, your manual calculation is likely very close to the correct logic already. Yes, it should be possible to work backward from the final figure to identify the exact annualization and rounding method used by the portal.

Because the portal uses the actual number of days in the year (365/366), the difference will probably come from one of these areas:

• Exact daily-rate annualization formula
• Whether the deductible is applied before or after annualization
• Intermediate rounding to 2 decimals at each stage
• How the annual rebate is prorated
• Whether taxable income is rounded before applying the tax slab

In many payroll systems, even a small rounding adjustment during annualization can change the PAYE by several Rand.

One approach would be to:

• Start from the portal PAYE value (652.99)
• Reconstruct the annual tax before rebate
• Add back the rebate
• Reverse the slab formula
• Compare the resulting annual taxable income with your worksheet value

That should help identify the exact point where the variance occurs.