What Is a Good ACoS on Amazon Australia? The Formula and Break-Even ACoS From Your Margin

A good ACoS on Amazon Australia is one that sits below your break-even ACoS, and your break-even ACoS equals your profit margin before ad spend. ACoS is advertising cost of sales: ad spend divided by sales attributed to those ads. Amazon does not publish an average or recommended ACoS for Australia, so a figure like "25% is good" is a rule of thumb, not a standard. Your target comes from your own numbers: price, Amazon fees and cost of goods. The worked example below uses fees from Amazon's Australian pricing page.

What is the ACoS formula?

ACoS = ad spend / ad-attributed sales x 100.

If you spend A$20 on clicks and those clicks lead to A$80 of attributed sales, ACoS is 20 / 80 = 25%. The inverse is ROAS: 80 / 20 = 4.0. See the ACoS and ROAS glossary entries.

Two details matter.

• ACoS only counts sales Amazon attributes to the ad. It ignores organic sales that the ad helped create. TACoS divides ad spend by total sales to show that wider effect.
• Attribution has a window and a product scope. Sales credited to a click can include other products from the same seller, depending on the report. Read the column definitions in your console before you compare numbers across reports.

For how ads are billed, see the Amazon ads overview for Australia. Amazon charges only when an ad is clicked.

How do you calculate break-even ACoS?

Break-even ACoS is the share of the sale price you can spend on advertising before the sale makes no profit. The steps follow.

1. Start with the selling price.
2. Subtract the referral fee, which is a percentage of the total sales price including delivery and gift wrapping.
3. Subtract the fulfilment cost: the FBA fee, or your own shipping if you fulfil.
4. Subtract cost of goods, landed in Australia (product, freight, duty and prep).
5. Subtract any other per-unit costs, such as storage allowances or returns.
6. Divide what is left by the selling price. That percentage is your break-even ACoS.

For example, a product with a 34% margin before ads can spend up to 34% of each sale on ads and still break even on that sale. Spend more and you lose money on every ad-driven order.

What does a worked A$ example look like?

This is illustrative. The price and cost of goods are invented for the example; the two Amazon fees are taken from Amazon's public rates. For simplicity, treat every figure as excluding GST. If your listed price includes GST, remove GST (one-eleventh of the GST-inclusive price) before you start, and check whether your ad reports show sales with or without GST.

Assume a home and kitchen product that sells for A$40.00, ships in an FBA parcel weighing 501 to 1,000 g, and costs A$12.00 landed.

Amazon's page notes selected FBA fees were reduced effective 10 June 2026, so check the current rate for your size tier before you use this table for real. The Amazon Australia FBA fees guide covers the tiers, and the profit calculator automates the sum.

Now see what different ACoS levels do to profit per ad-driven order in this illustrative example.

So for this seller, "a good ACoS" is anything comfortably below 33.95%, and 23.95% or lower if they want a 10% profit margin after ads.

How do you turn break-even ACoS into a maximum bid?

Break-even ACoS also caps what a click can cost. Maximum cost per click at break-even = profit before ads x conversion rate (orders per click).

In the example above (illustrative figures), with an assumed 10% conversion rate, break-even CPC is A$13.58 x 0.10 = A$1.36. To earn a 10% margin after ads, the cap is (A$13.58 - A$4.00) x 0.10 = A$0.96. Bids above that lose money on average.

Your real conversion rate will differ, and it moves by keyword. See the bidding guide for how to set bids from this cap.

What counts as ad cost, and what does not?

Only clicks are charged on Sponsored Products and Sponsored Brands CPC campaigns; impressions are free. There is no monthly fee for the ads themselves, so ACoS covers click spend alone. The A$49.95 Professional plan fee is a selling cost, not an ad cost. If you want a full picture of profit, spread that fee across your units in step 5 of the break-even calculation. Agency or software fees are also outside ACoS; count them separately when comparing options. See agency vs in-house.

Should you accept a higher ACoS on a launch?

Sometimes. A new product with no reviews may convert poorly, and sellers often accept an ACoS above break-even for a set period to gather sales and reviews. The risk is that "temporary" becomes permanent. If you do it:

• Set a ceiling (for example, a maximum weekly loss you can afford) and a review date.
• Use TACoS to check that organic sales rise as ad spend works.
• Tighten bids once reviews and sales history build.

The launch plan is covered in Amazon PPC launch strategy.

Amazon lists a recommended minimum daily budget of 15 in local currency for Australia (A$15; confirm it in your ads console). Budget size and ACoS are separate decisions: budget caps total loss; ACoS tells you whether each unit of spend earns.

Why do published "average ACoS" numbers mislead?

Averages blend categories, price points, margins, brand and non-brand terms, and launch and mature products. A 40% ACoS may be fine for a 60%-margin product and ruinous for a 20%-margin one. We do not quote an Australian average because Amazon does not publish one and no reliable public source exists. Use these checks instead.

• Compare each product to its own break-even ACoS.
• Compare campaign types separately: branded and exact-match campaigns usually run lower than discovery campaigns.
• Compare periods that are alike: a sale event is not a normal week.

An Amazon PPC audit checks whether campaigns beat their targets.

FAQ

What is a good ACoS on Amazon Australia? One below your break-even ACoS, which is your profit before ads divided by the selling price. In our illustrative A$40 example that is 33.95%, and 23.95% leaves a 10% margin. Amazon does not publish an Australian benchmark.

Is 30% ACoS good? It depends on margin. At a 34% break-even, 30% earns a small profit. At a 25% break-even, it loses money on each ad-driven order. Compare it with that product's break-even, not a general rule.

What is the difference between ACoS and ROAS? They are inverses. ACoS is spend divided by sales; ROAS is sales divided by spend. A 25% ACoS equals a 4.0 ROAS. Many sellers use ROAS for the same decision, just expressed the other way up.

Does ACoS include GST? It depends on whether your sales and price figures include GST. Amazon's fee rates are quoted excluding GST. Check your report definitions, work in one basis consistently, and confirm tax treatment with a registered tax agent. This is general information, not tax advice.

Why is my ACoS high but sales growing? Ads may be lifting organic sales, so TACoS can fall while ACoS stays high. That is only fine if total profit holds up. Track TACoS and profit per unit, and set a review date for any launch overspend.

Should I optimise for low ACoS? Not at any cost. A very low ACoS can mean you are bidding too little to win volume. Aim for an ACoS under break-even that still delivers the sales and profit you need.

Next step

Work out break-even ACoS for each product, then set bids from it. If you would like specialists to apply it across campaigns, Blooprint offers Amazon Ads management for Australian sellers. The Australia hub lists related guides.