GST Calculator
Add or remove GST and calculate receipts after entered processing fees.
Amount and GST rate
Enter the price before GST to add GST, or the total including GST to remove it.
Defaults to Australia's 10% GST. Enter another applicable rate if needed.
Payment processing fee (optional)
Applied to the GST-inclusive payment. Leave 0 for no percentage fee.
Use the treatment on your processor's tax invoice. Fee GST uses the rate above.
Results
Correct the marked input to calculate GST.
GST amount
$275.00
At the GST rate enteredGST-exclusive amount
$2,750.00
Before GSTGST-inclusive total
$3,025.00
Including GSTReceived after fees
$3,025.00
Total less the processing feeAdding 10% GST to $2,750.00 gives $275.00 GST and a total of $3,025.00.
GST and payment breakdown
The processing fee is charged on the GST-inclusive total. It does not change the GST on the sale.
| Measure | Amount |
|---|---|
| GST-exclusive amount | $2,750.00 |
| GST at 10% | $275.00 |
| GST-inclusive total | $3,025.00 |
| Processing fee as quoted | $0.00 |
| GST in the processing fee | $0.00 |
| Processing fee charged | $0.00 |
| Amount received after the fee | $3,025.00 |
| Received less GST on the sale | $2,750.00 |
Models one taxable sale. GST and fees round to cents, with half cents rounding up.
Fee GST appears separately. It is not offset against GST on the sale.
PDF opens your print dialog. CSV includes inputs and results. Your entries stay in this browser.
Adding and Removing GST
To add GST, multiply the amount before GST by 10% and add the result. To find the GST included in a total at 10%, divide the total by 11. Australia's GST is 10% on most goods and services, as the ATO's guide to how GST works explains. The rate is the same in every state and territory, including NSW, Victoria, Queensland and WA.
The divisors differ because the 10% rate applies to the price before GST, also called the GST-exclusive or ex-GST price. A GST-inclusive total is 110% of that price. Its GST is therefore 10/110 of the total, which is one-eleventh. The business.gov.au guide to registering for GST uses the same fraction: a $1,100 computer bought including GST carries $100 GST.
- Incorrect: $110 × 10% = $11 GST. This applies the rate to a total that already includes GST, so it overstates the tax.
- Correct: $110 ÷ 11 = $10 GST, leaving $100 before GST.
For any rate, the GST in a total equals the total × rate ÷ (100 + rate). New Zealand's GST rate is 15%, according to Inland Revenue's GST guide. At that rate, GST is 15/115, or 3/23, of a total that includes it. Enter 15% in the GST rate field to use it.
Reverse GST Formula
The reverse GST formula divides a GST-inclusive total by 11 to find the GST, then subtracts that GST to find the amount before GST. For example, $100 before GST plus $10 GST gives a $110 total. Reversing it, $110 ÷ 11 = $10 GST, and $110 less $10 leaves $100 before GST.
Small amounts need cent rounding. At $0.05 before GST, the GST is exactly half a cent. For a tax invoice with one taxable sale, the ATO's tax invoice rules round GST to the nearest cent, rounding 0.5 cents up. GST becomes $0.01 and the total $0.06. Reversing $0.06 gives about 0.55 cents of GST, which also rounds to $0.01, so the amount before GST returns to $0.05.
The calculator rounds the GST first, then adds it to the amount or subtracts it from the total. The amount before GST and the GST therefore always add up to the total shown. For an invoice with several taxable sales, the ATO allows rounding on the invoice total or on each sale. The two methods can differ by a cent.
Fees, Commission and Net Receipts
Work out GST from the amount the payer is charged, before a processing fee comes out. The processor's fee is a separate charge and does not change the GST on your sale. The calculator shows the GST on the sale, the fee and the amount received as separate figures.
In this hypothetical example, a client pays a $110 invoice including GST by card. The processor charges an entered 2.5% plus $0.30, so the fee is $2.75 plus $0.30, or $3.05. You receive $106.95, and the GST on the sale stays $10. After setting that GST aside, $96.95 remains.
- Incorrect: $106.95 ÷ 11 = $9.72 GST. The fee does not reduce the price of your sale.
- Correct: $110 ÷ 11 = $10 GST, worked out before the fee.
Enter the percentage and fixed fee from your own processor's current pricing, whether that is PayPal, a card terminal or another payment service. The example rates are not any processor's published price.
Processing fees do not all carry the same GST treatment. A fee can include GST, have GST added to the quoted rate or carry no GST. The ATO treats financial supplies, such as lending money, as input-taxed sales with no GST in their price. Choose the treatment your processor's statement or tax invoice shows. If the processor adds GST to the $3.05 fee in the example, the fee becomes $3.36 including $0.31 GST, and you receive $106.64.
GST credits depend on eligibility and supporting records. The calculator separates fee GST without claiming a credit or netting it against GST on your sale.
The same split applies to commission that includes GST. For commission paid with a recipient-created tax invoice (RCTI), use the GST treatment shown on that invoice. Choose Remove GST and enter the GST-inclusive commission to check it. Reading an RCTI and commission statement shows how to match that GST to the deposit after deductions.