GST Quote Calculator for Australian Tradies

GST is 10%, and it goes on top

The ATO describes GST as a broad-based tax of 10% on most goods, services and other items sold or consumed in Australia. For a tradie that means the labour and materials on nearly every job. Adding it is the easy direction: multiply the ex-GST price by 1.1. A $1,000 job becomes $1,100 and the extra $100 is the GST you collect for the ATO. It is not your income and it should never be counted as profit.

You only add GST if your business is registered for it. The ATO's registration page sets the threshold at a GST turnover of $75,000 or more, and says registration is optional below that. Not registered? Then there is no GST line on your quote and you cannot issue a tax invoice. If you are close to the threshold, read do I need to put GST on a quote before your next big job, because crossing it changes every price you send.

The divide-by-11 rule

Going the other way trips people up. If a total already includes GST, the GST inside it is one eleventh of the total, not 10% of it. The reason is simple: the inc-GST total is 110% of the ex-GST amount, so the GST is 10 parts out of 110. The ATO's own tax invoice rules describe the GST as exactly 1/11 of the total price on a fully taxable sale.

Check it: $2,500.00 x 1.1 = $2,750.00. Take 10% off the total instead and you get $275.00 of GST, which overstates it by $25.00, and the ex-GST figure you then compare to your costs is too low. That matters when you are checking the profit on a job, because the job profit calculator works on ex-GST money and so should you.

Quoting a homeowner? Show the total including GST

When you show a price to a consumer, the ACCC's price display rules say the total price must be displayed as a single figure, and that figure must be the minimum total cost including any taxes. You can still show the ex-GST amount as a component, but the inc-GST total has to be at least as prominent. The ACCC notes an exception for prices shown only to other businesses, which is why quoting a builder ex-GST is common practice.

The habit that keeps you out of trouble on both sides is three lines on every quote: the ex-GST amount, the GST, and the inc-GST total. A homeowner sees the number they will actually pay. A builder can read the ex-GST figure they will claim against. And nobody rings you a week later arguing about whether "$2,500" had GST in it or not. If the price on the document is an estimate rather than a fixed quote, say so - the difference is spelled out in quote vs estimate.

Tax invoice basics

Once you are registered, your invoices need to be tax invoices. The ATO's tax invoice page says that if a customer asks for one you must provide it within 28 days, unless the sale is $82.50 inc-GST or less. For taxable sales under $1,000 it lists seven details the document must make clear:

• That the document is intended to be a tax invoice.
• The seller's identity.
• The seller's ABN.
• The date the invoice was issued.
• A brief description of the items sold, including the quantity (if applicable) and the price.
• The GST amount payable, shown separately or, when the GST is exactly 1/11 of the total, as the words "Total price includes GST".
• The extent to which each sale on the invoice is a taxable sale.

For sales of $1,000 or more the ATO adds one more line: the buyer's identity or ABN. Most trade jobs clear that bar, so the simplest approach is to put the customer's name and address on every invoice and never think about it again. TrackYaTradie quotes and invoices carry your business details and show the GST as its own line when you are registered for GST, so the documents you send are built for these rules from the start.

GST is the last step in pricing, not the first. Get your charge-out rate right so labour covers its true cost, put a markup on the job with the markup vs margin calculator, then add GST to the ex-GST price. Once the job is running, tracking hours and costs against that price is what job costing means in practice, and it is the part TrackYaTradie does for you.

Common questions