Small Business Calculators Australia

Decision guides and worked examples

Use these guides to check assumptions, understand the formulas and stress-test the result before acting.

• Break-Even ROAS vs Profitable ROASCalculate the ad-spend threshold that covers variable costs and the stricter ROAS needed to fund overhead and profit.
• Ecommerce Contribution Margin ExplainedMeasure the money each order contributes after variable costs but before fixed overhead.
• How GST Affects Ecommerce Profit in AustraliaRemove GST correctly from customer revenue and avoid overstating margins, CAC limits and ROAS.
• How Returns Change Your Real Customer Acquisition CostInclude refund rate, reverse logistics and lost product value when judging ecommerce advertising.
• How to Price Products When Discounts Are ExpectedSet an Australian ecommerce price that remains viable after normal promotions, GST, fees and returns.
• Gross Margin vs Net Profit in EcommerceUnderstand the layers between product margin, contribution after ads and final business profit.

Useful supporting calculators

Use these focused tools to check individual figures alongside the broader decision calculators.

• GST Calculator AustraliaAdd, remove or isolate Australian GST.
• Profit Margin CalculatorCheck profit as a percentage of revenue.
• Markup CalculatorCalculate price from cost and markup.
• Unit Price CalculatorCompare cost per unit or package size.

Why basic markup regularly underprices a business

Markup only compares the selling price with a selected cost. It can miss payment processing, GST, packaging, fulfilment, advertising, refunds, returns, discounts and the owner’s time. A 100% markup does not automatically mean a 50% net profit margin once those costs are included.

The product-pricing calculator solves backwards from a target profit margin while accounting for both fixed and percentage-based selling costs. It displays the GST component, break-even price and profit per sale so the assumptions remain visible.

Why a sole trader cannot divide salary by billable hours

An employee’s salary is supported by paid leave, employer super, equipment, administration, insurance and a steady flow of paid hours. A sole trader must fund those items from the rate charged to clients. They also spend time quoting, marketing, invoicing, learning, travelling and following up work that may not be billable.

The hourly-rate calculator starts with the income you want to retain, adds business costs and buffers, then divides the total by realistic billable hours—not every hour you intend to work.

GST registration and tax are not interchangeable

GST collected from customers is generally not business income available to spend. Income tax is separate and depends on taxable profit and the owner’s circumstances. The calculators separate GST from tax and super buffers rather than combining them into one vague percentage.