Free Amazon FBA calculator UK: fees, profit and ROI (2026)

The calculator above does the sum. Below it is every fee behind the number, and why each one moves.

Every retail arbitrage buy comes down to one sum: what the item sells for, minus everything Amazon takes, minus what you paid. Get that sum right and each buy is a decision. Get it wrong and you find out six weeks later, when the payout is smaller than the shopping bill. This is a walk through every fee that sits inside an Amazon FBA calculator for UK sellers, what each one depends on, and the places a calculator quietly gets it wrong.

The numbers below describe Amazon's UK rate card effective 1 July 2026, whose non-peak UK rates are unchanged from February, and which retailscout's own fee model and the calculator above are built on: 22 referral categories, envelope and parcel size tiers, a general parcel table and a separate one for selected categories, and the festive peak rates from 15 October 2026 to 14 January 2027. Amazon changes these, so treat any figure you read anywhere, here included, as something to check rather than memorise.

What an FBA calculator actually has to get right

A calculator is only as good as the four things it needs to know: what the item sells for, what category Amazon files it under, how big and heavy it is once packed, and what it cost you. Miss any one of those and the answer is confident and wrong. Category drives the referral fee. Size and weight drive the fulfilment fee. Price drives both, because several fees step at price thresholds. And your own cost is the one number Amazon has never heard of.

The referral fee, and the price tier most people miss

The referral fee is Amazon's commission on the sale, charged on the total price whether you fulfil the order yourself or Amazon does. Most people carry "about 15 percent" in their head, and for a lot of categories that is right. The trouble is the exceptions, and they are not small.

• Consumer electronics and computers sit at 7 percent.
• Tools and home improvement sit at 13 percent.
• Amazon device accessories sit at 45 percent.
• Clothing steps through 5, 10 and 15 percent as the price rises.
• Automotive charges a lower rate on the portion of the price above a threshold.

The part that catches sellers out is that several categories are tiered by price, not flat. Grocery is 5 percent at or under £10 and 15 percent above it. Beauty, health and personal care is 8 percent at or under £10 and 15 percent above. Vitamins and supplements do the same 5 to 15 step. Home is 8 percent at or under £20 and 15 percent above.

That is a cliff, not a slope. A supplement at £9.99 pays roughly 50p in referral. The same supplement at £10.01 pays roughly £1.50. Three times the fee for two pence of extra revenue. If your calculator applies one flat percentage taken from wherever the listing happened to be priced when the data was collected, it will bill you 5 percent on a £15 sale, and the deal will look about a pound a unit better than it is. On a case of 24 that is the whole margin.

There is also a floor. Most categories carry a minimum referral fee of £0.25 per item, so very cheap items do not get a proportionally tiny commission. Media, books included, is exempt from that minimum but carries a £0.50 closing fee instead, which is the one fee people forget entirely when they price up a pallet of books.

The fulfilment fee, and why size tier is where estimates go wrong

The fulfilment fee is what Amazon charges to pick, pack and ship the unit. It is not a percentage. It is a lookup: Amazon measures the packaged unit, drops it into a size tier, and charges the rate for that tier and weight band. Envelopes come first, then parcels, then oversize, each with its own dimension caps and weight limits. For parcels, the weight that counts is usually not what the scales say: Amazon uses the greater of the unit weight and the dimensional weight, which is length times width times height in centimetres divided by 5,000, in kilograms. A light but bulky box is billed as if it were heavier. Clothing, accessories, rucksacks and handbags are the exception, billed on unit weight.

There are also two parcel tables, not one. Most categories use the general table. Amazon's selected categories, among them grocery, clothing, footwear, pet clothing and food, home linen and rugs, and luggage accessories, use a separate table with its own size bands, charged on unit weight. So the same box can cost a different amount depending on what is inside it.

Because it is a lookup rather than a formula, being slightly wrong about a dimension is not slightly wrong about the fee. A box six millimetres too deep drops out of one tier and into the next, and the fee steps. This is why a calculator that guesses the tier from rough dimensions can be out by a pound a unit in either direction, and why it matters whether the figure you are looking at is Amazon's own published fee for that specific product or a model's reconstruction of it.

In the deal analyser, without a connected Amazon account, retailscout uses Amazon's published fulfilment fee for the product wherever there is an active FBA offer to read it from, and falls back to a dimensional model only when there is not. The two are labelled differently in the breakdown, so you can see which one you are looking at rather than having to trust it blind. The calculator at the top of this page has no product to read a fee from, so it always shows the model, and says so. Connect your selling account and the analyser goes a step further, which is the section on Amazon's own fees below.

Low-Price FBA, and its two different thresholds

Amazon runs a cheaper fulfilment rate for small, light, inexpensive units, which matters enormously in arbitrage because that describes a great deal of supermarket clearance. The catch is that the price threshold is not one number. For most categories it is £20. For beauty, health and personal care, business, industrial and scientific supplies, office products, grocery, books, Amazon device accessories and kitchen, it is £10.

So the same £15 sale price qualifies for the cheaper rate in one category and not in another, and the unit also has to be small and light enough to sit in the qualifying size bands. A calculator that applies a single threshold across every category will either overstate your fees on a £15 toy or understate them on a £15 shampoo. Neither error is one you want while standing in an aisle deciding whether to clear the shelf.

What the rate card actually charges, shape by shape

Searches for the FBA rate card usually want one thing: the actual numbers, for something the size of what is in the trolley. The card itself is twenty-odd pages of size bands, and reading it cold gives you every figure except the one you need. So here is the card priced for seven shapes a UK arbitrage seller genuinely picks up, worked out by the same fee model that runs the calculator at the top of this page.

Every figure is the fulfilment fee only, on Amazon's UK rate card effective 1 July 2026, at standard rates outside the festive peak window, with the 1.5 percent fuel surcharge already in it and nothing of your own added. Sizes are the packed box rather than the product, because that is what Amazon measures.

• Envelope - a boxed pack of trading cards, 19 by 12 by 2 cm, 60 g, selling at £12.99. Tier: envelope. Fulfilment £1.54.
• Large envelope - a small beauty item, 15 by 6 by 4 cm, 120 g, at £9.99. Tier: large envelope. Fulfilment £2.46.
• Small parcel - a shampoo bottle, 20 by 6.5 by 6.5 cm, 350 g, at £9.99. Tier: small parcel. Fulfilment £2.74.
• Small parcel, selected category - a grocery multipack, 34 by 24 by 11 cm, 900 g, at £14.99. Fulfilment £3.12.
• The identical box, general table - the same 34 by 24 by 11 cm box at the same weight and price, filed under beauty instead of grocery. Fulfilment £3.30.
• Medium parcel - a boxed board game, 40 by 30 by 6 cm, 1.1 kg, at £24.99. Tier: medium parcel. Fulfilment £3.53.
• Large parcel - a small kitchen appliance, 30 by 22 by 22 cm, 1.5 kg, at £34.99. Tier: large parcel. Fulfilment £3.59.

The useful thing in that list is not any single figure, it is the spread. From the smallest envelope to the largest parcel Amazon will take at standard rates, the fulfilment fee moves by about £2.05. A pack of cards and a kitchen appliance cost almost the same to pick, pack and ship. The fee is close to a fixed cost per unit, and it does not care what the item sells for.

That single property explains most of what experienced sellers do. If fulfilment is roughly £1.54 to £3.59 whatever you are shipping, then it is a small share of a £30 sale and an enormous one of a £6 sale. On the shampoo bottle above, fulfilment alone is 27 percent of the sale price before Amazon has taken a penny of commission. This is why cheap units are the ones the rate card punishes, and why a clearance shelf full of 50p items is usually a worse aisle than it looks.

The fourth and fifth rows are the same cardboard box twice, £0.18 apart. Grocery is on Amazon's selected-category parcel table, which prices on unit weight, so the box is charged on its 900 g. Beauty is on the general table, which prices on the greater of unit and dimensional weight, and 34 by 24 by 11 cm works out at 1,795 g dimensional. Same box, same scales, different table, and nothing about the product tells you which one applies.

The £1 price rise that leaves you worse off

Two of the fees on that rate card step at a price, and on a cheap item the steps are close enough together to land on the same product. Take the shampoo bottle. Priced at £9.99 it is inside the £10 beauty threshold, so it pays an 8 percent referral fee and qualifies for Low-Price FBA fulfilment. Priced at £10.99, £1 more, it pays 15 percent and the standard fulfilment rate.

• At £9.99: referral £0.80, fulfilment £2.74, digital services fee £0.07, one month of storage £0.02. Amazon takes £3.63 and you keep £6.36.
• At £10.99: referral £1.65, fulfilment £3.05, digital services fee £0.09, storage £0.02. Amazon takes £4.81 and you keep £6.18.

Selling it for a pound more leaves you £0.18 worse off per unit. Not less profitable in percentage terms, actually worse off in pounds. Nothing on the shelf, the listing or the Keepa chart warns you, and a calculator carrying a single referral rate and a single Low-Price threshold will show the £10.99 price as the better one. It is the clearest argument there is for pricing a buy on the real card rather than a rule of thumb.

Storage is the quiet one on the same list. At standard rates, one month costs £0.02 for the shampoo bottle, £0.19 for the board game and £0.39 for the kitchen appliance. Pennies, and easy to leave out. In the October to December window the same three items cost £0.05, £0.38 and £0.77, and they keep being charged for every month the stock sits there. The fee that hurts is never the one month you planned for.

Read the list the other way and it is a sourcing instruction rather than an accounting one: the rate card rewards small, light, branded lines that sell above about £12, which is a fair description of the health and beauty aisle and a poor description of the seasonal homeware end. Our guide to the best shops for retail arbitrage in the UK goes chain by chain on where those lines actually sit.

The smaller fees that still move the answer

• Digital services fee - In the UK this is 2 percent added on top of your Amazon fees, meaning the referral, the fulfilment fee, storage and any closing fee. It is not charged on your own costs. Per unit it is pennies, across a quarter it is real, and a surprising number of hand-built spreadsheets do not have a line for it.
• Fuel and logistics surcharge - A 1.5 percent surcharge on FBA fulfilment fees, effective from 17 April 2026. Worth knowing where it is applied: Amazon's own published per-product fulfilment fee already includes it, so a calculator that adds it again on top of that figure is double-charging you. It only belongs on a modelled estimate.
• Monthly storage - Charged per cubic foot per month, and it roughly doubles for the October to December peak. Clothing sits on a cheaper rate. Because it is per month, the honest version of this fee depends on how long you think the stock will sit, which is a judgement about sell-through rather than a property of the product. Our walk through Amazon's peak fees and Q4 storage works one product through before and during peak.
• Long-term storage - An additional charge on units that have been sitting a long time. The discipline it is trying to teach is a real one: overbuying a slow line costs more than the dead capital.
• Returns and removals - Returns can carry a processing cost and removing unsold stock is not free. Leave some slack on higher-return categories rather than modelling it per unit.

The costs Amazon's own calculator does not know about

Amazon's revenue calculator answers a narrower question than the one you are asking. It tells you what Amazon takes. It does not know what you paid, what your prep costs, or what it costs you to get the box to a fulfilment centre. Those are yours to add, and they are the difference between a fee breakdown and a profit figure.

• Cost per unit, which for a multipack means the shelf price divided out properly.
• Prep, whether that is your own time, polybags and labels, or a prep centre's per-unit rate.
• Inbound shipping, usually easiest to carry as a rate per kilogram of the shipment.
• Anything else, a catch-all for the costs that are real but awkward, fuel for the sourcing trip included.

In retailscout these live in your settings rather than being retyped per product, alongside your minimum ROI, so the profit figure you see is on your numbers and not on a generic template. The point of putting them in settings is that a cost you have to remember to add is a cost you will eventually forget to add.

VAT, which moves the answer in both directions

If you are VAT-registered, you owe output VAT on your sales, but you can reclaim the VAT on Amazon's fees and, where the goods were bought VAT-inclusive, on your cost too. If you are not registered, you cannot reclaim the VAT Amazon adds to its fees, so your effective fee load is higher, though you are also not handing over a fifth of every sale.

The subtlety worth building in is that the VAT rate is a property of the item, not of you. Most goods are 20 percent, but plenty of what sits on a supermarket clearance shelf is zero-rated or reduced-rated, and treating a zero-rated grocery line as though it carried 20 percent output VAT will make a genuinely good buy look like a bad one. retailscout takes the item VAT rate per lookup for exactly this reason, and shows the figure that applies to you rather than both, so you are not reading the wrong one by accident.

A worked example, done properly

Take a health and beauty item you can buy on clearance at £4.50 and that sells on Amazon at £16.99. Illustrative figures, but the shape is the point.

• Sale price £16.99.
• Referral at 15 percent, because £16.99 is above the £10 beauty threshold, is about £2.55. At 8 percent it would have been £1.36, so the tier alone is worth £1.19 a unit.
• Fulfilment is £2.13, for a 20x15x2cm envelope at 150g. No Low-Price rate applies, because £16.99 is above beauty's £10 threshold.
• Storage for a couple of months on something that small is about 3p.
• Digital services fee at 2 percent of those Amazon fees is about 9p.
• VAT on those Amazon fees, which you cannot reclaim unless you are VAT-registered, is about 96p.
• Your cost £4.50, prep 20p, inbound 5p.

That lands at roughly £6.48 profit a unit on a £4.75 all-in cost, which is a strong ROI. Now change one thing: buy the same item at £8.50 instead of £4.50 and the profit falls to about £2.48, and the ROI falls by more than half. Same product, same fees, completely different decision. This is why the answer to "is this a good deal" is never a property of the product, and why what counts as a good ROI on a retail arbitrage buy is worth settling before you are standing in the shop.

These figures are for a seller who is not VAT-registered. If you are registered, you reclaim the VAT on Amazon's fees but owe output VAT on the sale: the same item nets about £5.36 rather than £6.48 when the £4.50 buy was VAT-inclusive and you reclaim that too, and about £4.61 if it was not.

FBA or FBM: what changes in the sum

Fulfilling orders yourself (FBM) rather than sending stock into Amazon (FBA) does not make the fee sum simpler. It moves the costs around: some lines disappear, one arrives, and whether you come out ahead depends on a number only you know.

• Gone - The fulfilment fee, monthly and long-term storage, and inbound shipping to a fulfilment centre.
• Still there - The referral fee, with the same category tiers and price cliffs, any closing fee, and the 2 percent digital services fee on those.
• New - Your own packaging and postage to the customer, on every order.

Run the health and beauty example above as FBM, on the same basis. Sale £16.99, referral still about £2.55, the digital services fee on that about 5p, VAT on those fees about 52p, cost £4.50. No fulfilment fee, no storage, no inbound, and prep folds into your own packing. That leaves about £9.37 before you post it, against £6.48 as FBA. So on this item FBM comes out ahead if packing and posting one unit costs you less than about £2.89, and FBA comes out ahead if it costs more. Change the size or the weight and that break-even moves, which is why the question deserves a calculator rather than a rule of thumb.

The fees are also only part of that choice. An FBM offer is usually not Prime, which changes how it competes for the Buy Box, and the time you spend packing orders is a cost that appears on no fee schedule. In the retailscout analyser the choice is a switch: FBA asks how many months you expect the stock to sit in storage, FBM asks for your postage cost, and the profit and ROI recalculate on whichever you pick.

When a fee cannot be priced, and why unknown beats zero

Sometimes there is no active FBA offer to read a fulfilment fee from and no usable dimensions to model one either. The tempting thing for a calculator to do is treat that as zero, because zero renders nicely and the profit number looks healthy. It is also the single most dangerous thing it can do: a missing fulfilment fee overstates your profit by the entire fee, and it does it silently, on exactly the obscure products where you are least able to sanity-check the answer yourself.

A calculator should say it does not know. retailscout marks that case as unknown rather than showing a confident £0.00, which is less satisfying to look at and considerably better for your bank balance. If you take one habit from this piece, make it this: when a fee line reads zero, find out whether that means free or means nobody knows.

Estimated fees or Amazon's own: know which number you are reading

Every fee figure a calculator shows you comes from one of three places, and it is worth knowing which. The first is a model: a rate card, plus the category and dimensions the calculator thinks the product has. The second is Amazon's published fulfilment fee for that product, read from an active FBA offer. The third is Amazon's own fee estimate for the product at the price you are looking at, asked for through a selling account. Each has less guessing in it than the one before. A model can file a product under the wrong category and bill you the wrong referral tier; the third leaves the category to Amazon, which is the one that files the product in the first place.

retailscout uses the third wherever it can. Connect your Amazon selling account in Settings, on a paid membership or during the free trial, and the profit figure is worked out on the fees Amazon returns for that product at that price. Our estimate shows first so you are not staring at a spinner, and Amazon's figure replaces it when it arrives. The same answer feeds the analyser and the other profit figures in the app, so one product at one price shows one profit wherever you look at it.

Under the profit sits a line naming every deduction: referral, fulfilment, any closing or other fees, and the digital services fee. Two parts of it stay ours, and say so. Amazon's answer does not usually include the digital services fee, so that 2 percent is added by us and marked as an estimate; and storage depends on how long you expect the stock to sit, which only you can judge. When Amazon cannot price every fee for a product, which happens most often when it is out of stock, or when no account is connected, the figure carries a small "Estimated fees" label instead of passing itself off as exact.

The connection is read-only, it is the same one behind our check on whether you can sell a product before you buy it, and disconnecting it in Settings deletes the results we fetched for you. One thing to keep in proportion: Amazon calls its figure an estimate too. It is the best number available before a sale, and your settlement report is still the final word on what a sale actually cost.

Doing this in a shop, not at a desk

All of the above is manageable at a kitchen table with a spreadsheet. It is not manageable on a trolley in a supermarket with forty minutes left before the school run, which is where arbitrage decisions actually get made. That gap is the whole reason deal analysers exist.

retailscout's deal analyser does this sum from a barcode scan: category and referral tier, size tier and fulfilment fee, the smaller fees, your prep and inbound and VAT settings, then profit and ROI on the price in front of you, with a 0 to 100 buy score and the price and rank history behind it. It is part of the membership rather than a separate subscription, at £14.99 a month with a 7-day free trial and cancel anytime.

The fees are also only half of a sourcing trip. Knowing a clearance line is profitable is no use if you drive to four shops that do not stock it, which is what our guide to Tesco clearance and how to route it is about.

The same sum decides an online buy, where the thing being judged is a price that moved rather than a yellow sticker. If that is the side you source on, our piece on how Amazon price drops work and how to catch them covers why a big percentage off tells you far less than the fee arithmetic underneath it.

A fee calculator on the Amazon page you are already on

Online sourcing puts the same sum somewhere else: a browser tab rather than an aisle. Copying an ASIN out of Amazon and into a separate calculator is exactly the kind of friction that turns checking every product into checking some of them.

The retailscout Chrome extension opens a side panel beside the Amazon product page you are on, and that panel is the deal analyser itself rather than a cut-down copy. Your cost, prep and VAT settings, the FBA or FBM switch and, with a connected account, Amazon's own fees all come with it. On a category or search page, right-click a product link and analyse that link without opening it. Highlight a price on a retailer's page and you can send it across as your buy price. The extension is included in the membership.

The takeaway

Amazon's fees are not complicated once they are laid out, but they are big enough, and stepped enough, that guessing them turns winners into losers. Check the referral tier rather than assuming 15 percent. Check whether the price sits above or below the category's threshold. Use Amazon's own fee figure for the product where you can get one, and know when you are looking at an estimate instead. Price FBM against FBA when the item is small enough to post. Add your own costs and your item's VAT rate, because Amazon will not. And treat a zero as a question rather than an answer.

If you are new to all of this, start with our beginner's guide to retail arbitrage in the UK. If you're still deciding which tool should be doing this sum for you, our guide to the best retail arbitrage apps for UK sellers compares what each one is actually for.

And the fee sum is only one of the checks a buy has to pass. Our walkthrough of the seven checks behind Amazon FBA deal analysis puts it in order alongside sales velocity, price history, seller counts and eligibility, and shows a beauty item where charging a pound more leaves you with less.