Seller profit calculators

We went through nineteen of them before building these. The pattern was consistent.

Stale fees. The deepest and most feature-complete eBay calculator on the web still states its fees are "current as of November 27, 2022" — before the present 13.6% structure existed. The largest tool farm in the niche, with 97 calculators across fifteen marketplaces, publishes no effective dates at all. Four of the nineteen give a fee date of any kind.

The 2026 Amazon changes. On 15 January 2026 fulfilment fees split into three price bands instead of one fee per weight tier. On 17 April a 3.5% fuel and logistics surcharge went on top of every FBA fee. Most calculators model neither, which understates the fulfilment fee by roughly fifteen to forty cents a unit.

VAT on the fees themselves. Marketplaces charge VAT on their own fees to sellers who have not supplied a VAT number, and you cannot reclaim it. One of the nineteen models this. Several ship UK and German pages with no VAT handling whatsoever, which makes their output materially wrong for exactly the sellers those pages target.

Returns. None of them model a return rate. A 6% return rate does not cost 6% of profit — it costs the outbound fulfilment fee you do not get back, the return handling, and the stock you cannot resell. On apparel it is the difference between a healthy margin and a loss.

Duty. Not one of the nineteen includes import duty in net margin. Since the US $800 de minimis exemption ended in August 2025, duty is often the single largest cost line for a seller importing from Asia.

If you sell in the UK, the EU, India or Australia, your listed price includes tax. That portion was never yours — you are collecting it for the tax authority and remitting it. A seller treating a £120 inclusive price as £120 of revenue overstates margin by the full twenty percent, which is usually more than their entire actual margin.

Every calculator here takes a tax rate and a mode, strips inclusive tax out of revenue, and still charges the marketplace commission on the gross figure — because that is what Amazon, eBay and Etsy actually do.

Your advertising dashboard tells you what your ACOS is. It cannot tell you what ACOS you can afford, because that depends on the fee stack sitting underneath the sale — the referral fee, the fulfilment fee, the surcharge, the landed cost of goods and your return rate.

Break-even ACOS is simply profit before advertising divided by selling price. If a $40 product makes $10 before ads, you can spend up to 25% of revenue on advertising before the campaign starts buying sales at a loss. Divide that $10 by clicks per order and you have a bid ceiling. Neither number exists anywhere in Seller Central.