Australian GST Calculator
Easily add or remove Goods and Services Tax (10%) from any amount.
Net Amount (Ex GST): $XX.XX
GST Component (10%): $XX.XX
Total Amount (Inc GST): $XX.XX
The Verdict: Is “Manual GST” worth the risk?
Best for: Aussie sole traders who need to quickly double-check a single receipt, and NDIS providers who need to ensure they aren’t accidentally overcharging participants for GST-free services.
The Reality: For most tradies, GST is a straightforward 10%. But for NDIS providers, it is a compliance minefield. If you charge GST on a service that the ATO deems “GST-free,” you are legally required to remit that money to the ATO anyway—meaning you can’t just keep it as profit. Conversely, if you don’t charge it when you should, that 10% comes directly out of your pocket during an audit.
The Bottom Line: Use this calculator for a quick fix, but don’t rely on “mental math” for your BAS. Sole automatically applies the correct 2026 GST logic to your NDIS invoices and expenses, ensuring you claim every cent of your “Input Tax Credits” without the headache of manual calculations.
How to Calculate GST Manually
If you don’t have a calculator handy, here are the simple formulas used by the ATO:
- To Add GST: Multiply your figure by 1.1.
- Example: $\$100 \times 1.1 = \$110$
- To Remove GST: Divide the total figure by 11.
- Example: $\$110 \div 11 = \$10$ (This is the GST amount).
- To Find Ex-GST Price: Divide the total figure by 1.1.
Do NDIS Providers Charge GST?
This is one of the most common questions we get. Generally, most NDIS supports are GST-free if:
- The client is an NDIS participant.
- The supply is “reasonable and necessary” as per their plan.
- The service is listed in the NDIS Determination.
However, you still need to deal with GST if:
- Expenses: You pay GST on your business expenses (fuel, laptops, supplies). You can claim this back as “Input Tax Credits.”
- Non-NDIS Work: If you do private work alongside NDIS work, that private work is likely taxable.
Registration: If your turnover exceeds $75,000, you must register for GST, even if your sales are GST-free.
Make “BAS Time” Boring
Calculating GST on a single receipt is easy. Tracking GST across 12 months of expenses and income for your Business Activity Statement (BAS) is hard.
Sole does it for you:
- Expense Tracking: We automatically extract the GST from your receipt photos.
- Real-Time Estimation: See exactly how much GST you’ve collected vs. how much you’ve paid.
- Instant Reports: Generate a BAS-ready report in one click.
Hourly Rate Calculator – Ensure your rate covers your tax obligations.
Sole Trader Tax Guide – Understand your wider tax responsibilities.
Australian GST & NDIS: Frequently Asked Questions
What are the “Four Pillars” for GST-free NDIS services?
To legally provide a service GST-free under Section 38-38 of the GST Act, you must meet all four of these criteria:
- The participant must have an active NDIS plan.
- The support must be “Reasonable and Necessary” as defined in that plan.
- There must be a written agreement (like a Service Agreement) between you and the participant.
- The service must be a “legislated” support listed in the 2021 NDIS Determination (which has been extended through 2027).
What happens if I accidentally charge GST on an NDIS invoice?
If you charge GST in error, the ATO still requires you to remit that amount. To fix this, you must issue a Credit Note to the participant or Plan Manager for the full amount, then issue a new GST-free Tax Invoice. You must then refund the overpaid GST portion to the client. Sole makes this “Void and Reissue” process simple to keep your ledger clean.
I’m under the $75k threshold. Do I still need this calculator?
If you aren’t registered for GST, you cannot charge it on your invoices, and you cannot claim back the GST you pay on supplies (like fuel or tools). However, once you hit that $75,000 turnover, registration is mandatory. Many NDIS providers choose to register early so they can claim “Input Tax Credits” on their business overheads, even if their NDIS income remains GST-free.
Are “Non-Face-to-Face” supports also GST-free?
Yes, provided they meet the same four criteria as your direct support. If you are writing a report or doing plan-related admin that is a “reasonable and necessary” part of the participant’s care, it is typically GST-free.
What is a “Mixed Supply” invoice?
This happens when you sell a taxable item (like a general-purpose piece of equipment) alongside a GST-free service (like therapy). Your invoice must clearly itemize which parts include GST and which do not. Sole’s invoice builder handles mixed supplies automatically, calculating the 10% only on the specific items you flag as taxable.
Can a Plan Manager reject my invoice if I add GST?
Yes. If a service is legally GST-free, a Plan Manager may reject the invoice to protect the participant’s budget. Furthermore, if adding 10% GST pushes your total price above the NDIS Price Limit, the invoice will be rejected immediately.