Amazon FBA calculator for UK sellers.
Paste an ASIN and Amazon fills in the box, the category, the live buy box price and its own fee estimate for that product. Or type the numbers yourself. Either way you get the referral fee, the fulfilment fee, the digital services fee and VAT taken off in the right order — with the profit, margin, ROI and break-even price that are left. No sign-up, no email.
We ask Amazon for the packed size, the weight, the category, the live buy box and Amazon's own fee estimate for that ASIN, then fill the form in. Every field stays editable.
Where the numbers come from
Type an ASIN and the size, weight, category and live buy box price come from Amazon's own catalogue and offer listing, along with Amazon's fee estimate for that specific product. Type the numbers instead and the fulfilment fees come from Amazon's published UK rate card, effective 1 July 2026, read straight off the table, with the referral percentages from the UK column of the same document. Nothing here is an average: a size and weight Amazon does not publish a rate for is reported as unavailable rather than filled in with something plausible.
Why the two can disagree
The rate card is the schedule; Amazon's estimate is what it says it would charge for one particular ASIN today, and the two differ often enough to matter — a product Amazon has classified into a different fee group, a fulfilment rate that has moved since the card was published, a promotion. When both are available the page shows them side by side rather than picking one quietly, and the estimate from Amazon is the one used by default.
The dimensional weight trap
Amazon charges a parcel on the greater of its actual weight and its volume converted to weight. A 30 × 20 × 10 cm box weighs 1.2 kg as far as the fee is concerned no matter what is inside it, so a light product in a roomy box is charged as though it were heavy. Envelopes are the exception — those go on real weight alone. This calculator applies the rule Amazon applies, which is why the charged weight is shown next to the answer.
VAT, three ways
The same price, cost and fee mean three different profits depending on how you are registered, and most calculators model one of them. A registered seller hands a sixth of the shelf price to HMRC and reclaims the VAT on stock and fees. A seller below the threshold hands over nothing but pays 20% more for stock, prep and Amazon's fees than the headline figures suggest. The Flat Rate Scheme trades the reclaim away for a flat percentage of gross turnover. Pick yours and the whole decomposition changes.
Break-even, not guesswork
The break-even figure is the lowest price at which this unit stops losing money, solved against the same fee logic rather than approximated — which matters, because dropping the price can move you into a cheaper referral band or qualify the listing for Low-Price FBA. It is the number to set as your floor if you reprice automatically.
- Oversize tiers. Anything past a standard parcel (45 × 34 × 26 cm, 11.9 kg) is charged as a base fee plus a per-kilo rate across six overlapping tiers. Those are on Amazon's rate card.
- Amazon's "selected categories" parcel table. Footwear, clothing, grocery, mattresses and a dozen others use their own parcel rates and are weighed on real weight only.
- Storage and the rest. Monthly storage, long-term storage, removals, returns processing and low-inventory cost coverage are all real and none of them are per-unit-at-the-sale. Folding an average into a per-unit answer is how a calculator quietly misleads you.
- Your cost of goods. Amazon knows the fees; only you know what you paid. Connect your account and Eve keeps a cost against every SKU so this maths runs itself.
This is the arithmetic. Eve is the rest of it.
A calculator answers one question about one product. Connect your Seller Central account and Eve answers it for every SKU you own and every line of a supplier list, using the fees Amazon actually charged you.
Common questions.
Is this calculator free?
Yes, and there is nothing to sign up for. The arithmetic runs entirely in your browser. The only thing that leaves your device is the ASIN, if you choose to look one up — never your costs, your prices or anything else you type.
What happens when I enter an ASIN?
We ask Amazon four things about it: what the product is, the dimensions and weight of the box Amazon ships, what it currently sells for, and what Amazon estimates it would charge in referral and fulfilment fees. Those fill the form in and every field stays editable — if Amazon's packed dimensions look wrong for how you send it, change them. Your cost of goods is the one number nobody can look up for you.
How accurate is it?
With an ASIN, the referral and fulfilment fees are Amazon's own estimate for that product, so they are as accurate as anything short of your own fee reports. Entered by hand, the fees are Amazon's published UK schedule applied with Amazon's own size-tier and dimensional-weight rules, which for a product inside the envelope and parcel tiers should match Amazon's own revenue calculator to the penny. Either way, storage, returns and removals are charged separately from the sale and are not in this number.
Why does my light product cost so much to ship?
Almost always dimensional weight. Amazon charges parcels on the greater of the real weight and the box volume divided by 5,000, so a 30 × 20 × 10 cm box is charged as 1.2 kg however little is in it. Shrinking the box is often worth more per unit than shaving the product's weight. The calculator shows the charged weight next to the answer so you can see which one is being used.
What is the digital services fee?
A charge Amazon adds on top of the referral and fulfilment fees, worth 2% of the two combined in the UK. It is small per unit and easy to leave out, which is exactly why it is worth including — it is the difference between a 3% margin and a 2% one.
What is Low-Price FBA?
A cheaper fulfilment rate Amazon applies automatically to products priced at £20 or less including VAT, or £10 or less in a handful of categories including Beauty, Health and Personal Care, Grocery, Books, Office Products and Kitchen. It is on by default here because Amazon applies it whether or not you ask. Untick it to compare.
Should I enter cost including or excluding VAT?
Excluding — the net figure on the supplier's invoice, in every VAT regime. If you cannot reclaim it, the calculator adds the 20% back for you. Entering it two different ways depending on registration is how a cost column ends up meaning two different things, and it is the single most common way these calculations go wrong.
Does it cover FBM or merchant-fulfilled?
Not directly. For a merchant-fulfilled listing, set the FBA side aside and treat your own postage and packaging as the prep cost — the referral fee, the digital services fee and the VAT arithmetic are identical.
Do you have a calculator for other marketplaces?
This one is Amazon UK. Inside the application the same maths runs against whichever marketplace your account is authorised for, using the fees Amazon reports back for your own listings rather than a published schedule.
Now do it for your whole catalogue.
Eve connects to Seller Central, reads the fees Amazon actually charges you, and runs this same decomposition across every order and every SKU you own. Free plan, no card.