Why this exists

I sell physical products in both the US and German marketplaces, and I kept running into the same problem. A SKU that my spreadsheet said was returning 18% was returning 11%. The tools I was checking against disagreed with each other and with Seller Central, and every one of them wanted my email address before it would show me a number.

So I built the calculator I wanted: one that shows the arithmetic, cites where each rate came from, and lets me put the same product against two marketplaces at once. Then I made it public, because the number of sellers who are quietly losing money on cross-border listings is much larger than the number who are talking about it.

Who maintains it

[Your name] — [one or two sentences: where you sell, what you sell, how long you have been doing it. Be specific. "I have run FBA inventory in the US and German stores since [year]" is worth more than any credential.]

Contact: [[email protected]]. Corrections about a fee rate are especially welcome — see the methodology page for how they are handled.

How it is funded

Today: it isn't. There are no ads, no affiliate links, no sponsored placements, and no email capture on this site. Nothing you enter into the calculator is transmitted anywhere — every calculation happens in your browser.

If that changes, it will be stated here and dated, before it changes.

What this site refuses to do

• It will not guess your fulfilment fee. It asks you for it, because that number is per-product and a category average is a lie with a decimal point.
• It will not ask you to sign up to see a result. The result is the point.
• It will not invent an accuracy claim. The referral rates come from Amazon's published schedules and the date they were retrieved is on every page that uses them.
• It will not give tax advice. It models the arithmetic of VAT. Whether you are registered, what rate your product attracts, and where you owe it are questions for an accountant.

What comes next

The obvious gap is the other European storefronts. France, Italy, Spain and Poland share most of the German fee structure but not the fee base, because the VAT rates differ. That is the next thing worth building — but only once this version has been checked against enough real accounts to trust it.

Known weaknesses

Two, and they are worth stating plainly. Fulfilment fees are only as good as what you type in. And the returns model is deliberately pessimistic — it assumes a returned unit is a total loss, which overstates the cost for categories where returns are resellable.

Both are documented on the methodology page rather than buried.