Reverse VAT calculation: how to remove 15% VAT
Have a VAT-inclusive price and need the amount before VAT? Here is the formula SARS uses, step by step, with worked examples in Rand.
A "reverse VAT" calculation takes a price that already includes VAT and splits it into the amount excluding VAT and the VAT itself. You need it whenever you only know the final price: a till slip, a quote, a supplier invoice or an online price. In South Africa this is common because, as the SARS VAT 404 Guide for Vendors (opens in new tab) puts it, all prices charged, advertised or quoted by a vendor must include VAT at the applicable rate. So the VAT-inclusive figure is usually the one you see first.
If you just want the answer, use the SA VAT Calculator and choose Incl. VAT (remove VAT). Read on to understand how it works and how to check it by hand.
The formula: the tax fraction 15/115
The standard VAT rate in South Africa is 15% (SARS: Value-Added Tax (opens in new tab)). A VAT-inclusive price is therefore made up of 100 parts of price plus 15 parts of VAT, or 115 parts in total. The VAT is 15 of those 115 parts. SARS calls this the tax fraction, and the VAT 404 guide uses 15/115 when working out the VAT contained in an amount.
VAT = VAT-inclusive amount × 15 ÷ 115
Amount excluding VAT = VAT-inclusive amount ÷ 1.15 (or the inclusive amount minus the VAT)
Both lines give the same answer. Dividing by 1.15 is the quickest way on a phone calculator; multiplying by 15/115 is the quickest way to get the VAT on its own.
Worked examples
Example 1: R115.00
R115.00 × 15 ÷ 115 = R15.00 VAT. The amount excluding VAT is R115.00 − R15.00 = R100.00. This is the simple case that proves the formula: 15% of R100 is R15, and R100 + R15 = R115.
Example 2: R1 000.00
R1 000.00 ÷ 1.15 = R869.5652…, which rounds to R869.57 excluding VAT. The VAT is R1 000.00 − R869.57 = R130.43. As a check, 15% of R869.57 is R130.4355, which rounds to R130.44, and R869.57 + R130.44 = R1 000.01. That one-cent difference is a rounding effect, explained below.
Example 3: R49.99
R49.99 ÷ 1.15 = R43.4696…, which rounds to R43.47. The VAT is R6.52.
Example 4: R2 300.00
R2 300.00 ÷ 1.15 = R2 000.00 exactly, so the VAT is R300.00. Round numbers that are multiples of 115 split cleanly; most amounts don't.
The most common mistake: taking 15% of the inclusive price
It is tempting to remove VAT by subtracting 15% of the VAT-inclusive price. That gives the wrong answer, because the 15% was originally calculated on the smaller, VAT-exclusive amount.
Take R1 000.00 including VAT. 15% of R1 000.00 is R150.00, which would leave R850.00. But adding 15% VAT back to R850.00 gives only R977.50, not R1 000.00. The correct VAT is R130.43, leaving R869.57. Taking 15% of the inclusive price overstates the VAT by R19.57 on every R1 000.
Equally, removing VAT is not the same as a 15% discount. Removing VAT from a price reduces it by about 13.04% (15 ÷ 115), not 15%.
Rounding to the cent
Most reverse VAT results have more than two decimals, so they have to be rounded. The SA VAT Calculator rounds the amount excluding VAT to the nearest cent, rounding half a cent up, and then works out the VAT as the difference. This means the two parts always add back up to the exact price you entered, which is usually what you want when you are splitting an invoice or a receipt.
Because of rounding, adding VAT to a rounded VAT-exclusive figure can occasionally land one cent away from the original inclusive price, as in Example 2. This is normal. Your accounting system may apply its own rounding rule, so for VAT returns always use the figures on your actual tax invoices rather than a recalculated amount.
Removing VAT from several amounts
If you have a list of VAT-inclusive amounts, such as items on a receipt, open Line items / bulk mode on the calculator. Each line is calculated and rounded on its own and the totals add up the rounded lines. If you instead remove VAT from the grand total, the result can differ by a cent or two from the sum of the lines. Neither approach is "wrong", but be consistent and follow what appears on the tax invoice.
When there is no VAT to remove
A reverse VAT calculation only makes sense if the price actually includes VAT at 15%. It does not apply to:
- Zero-rated supplies, which are taxed at 0%, such as certain basic foodstuffs listed in the VAT Act. There is no VAT inside the price. See zero-rated vs exempt supplies.
- Exempt supplies, such as certain financial services, residential accommodation and public transport, on which no VAT is charged.
- Sellers who are not registered for VAT. Only registered vendors charge VAT. See VAT registration thresholds.
To remove VAT at a different rate, type that rate into the calculator's rate field. The general tax fraction is rate ÷ (100 + rate).
Quick reference
| Incl. VAT | Excl. VAT | VAT |
|---|---|---|
| R49.99 | R43.47 | R6.52 |
| R115.00 | R100.00 | R15.00 |
| R1 000.00 | R869.57 | R130.43 |
| R2 300.00 | R2 000.00 | R300.00 |
For more amounts, see VAT on common amounts.
Sources
All checked on 10 October 2026.