Amazon FBA Calculator
Build the full FBA fee stack — referral, fulfilment, the fuel surcharge and storage that quadruples in the fourth quarter — and see the net that actually reaches you.
Amazon FBA Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Excludes advertising, returns processing and inbound freight.
- Referral rates vary by category and are periodically revised.
- Fulfilment fees depend on size tier and weight band.
In short: Storage is the seasonal trap. At 34.99 the fee stack is 11.94 — a 34.1265% take rate — and the same unit costs 3.0769 times more to store between October and December than it does the rest of the year.
Formula
fees = max(referral%, minimum) + fulfilment × (1 + surcharge) + storage
peak storage applies October to December
[('referral', 'on the TOTAL price including shipping'), ('surcharge', 'on fulfilment only, not on referral'), ('peak storage', 'Oct–Dec, several times the base rate'), ('not included', 'advertising, returns, inbound freight')]
Worked Example
- Take the greater of the referral percentage and the minimum.
- Add the fulfilment fee and its surcharge — not the referral's.
- Add storage at the off-peak rate.
- Re-check storage at the fourth-quarter rate.
- Deduct goods for the net, then subtract advertising separately.
A 34.99 unit pays 5.25 referral at 15%, 6.05 fulfilment plus a 0.21 fuel surcharge at 3.5%, and 0.33 storage at 0.42 cu ft × 0.78 — 11.84 in total, a 33.8296% take rate. From October to December the same unit costs 1.01 to store, 3.0769 times more. After 9.50 of goods the net is 13.65, a 39.0126% margin against a 72.8494% gross margin before fees. The professional plan pays above 40.39 units a month; at 420 units it costs 0.10 each.
Strengths & Limits Of This Model
Where this engine is strong
- Applies the surcharge to fulfilment only, as Amazon does
- Shows peak storage as a multiple of the base rate
- Honours the referral minimum on low-priced items
Where it stops
- No advertising term
- Size-tier fees vary
Practical Use Cases
Product selection
Testing whether a product survives the fee stack.
Seasonal planning
Pricing the fourth-quarter storage increase.
Pricing decisions
Finding the price a target margin requires.
Plan selection
Comparing professional against individual.
Channel comparison
Feeding the marketplace comparison page.
Methodology & Editorial Standards
The referral fee takes the greater of the percentage and the category minimum, matching how it is actually charged. The fuel and inflation surcharge is applied to the fulfilment fee ALONE, not to the whole stack, since applying it to the referral overstates cost. Storage is computed at both the standard and the fourth-quarter rate so the seasonal multiple is visible rather than discovered. Advertising, returns and inbound freight are deliberately excluded and named, because including estimates for them would disguise which figures are published rates and which are assumptions.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Amazon FBA Calculator — 10 Expert FAQs
10 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
What fees does Amazon charge FBA sellers?
A referral fee as a percentage of the sale price, a fulfilment fee per unit, a surcharge on that fulfilment fee, monthly storage by volume, and a subscription. Advertising, returns processing and inbound freight sit on top and are frequently the difference between a modelled profit and an actual loss.
Is the referral fee charged on shipping?
Yes. The referral applies to the total price the buyer pays including any shipping and gift wrap you charge, so raising shipping to protect your margin partly funds Amazon's commission instead.
Why does storage cost so much more in the fourth quarter?
Because warehouse capacity is scarcest when demand peaks, so the rate rises steeply from October to December — commonly around three times the base. Slow-moving inventory held through that window is where FBA margins quietly disappear, and aged-inventory surcharges compound it.
Does the fuel surcharge apply to the referral fee?
No, only to the fulfilment fee. Modelling it against the whole fee stack overstates your costs, and modelling it not at all understates them. It is a small distinction per unit that compounds across thousands.
What referral rate applies to my category?
It varies substantially — lower for electronics and computers, around fifteen per cent for most general categories, higher for apparel and jewellery, and very high for a few specialised ones. Verify your specific category rather than assuming the common figure.
What is the referral minimum?
A floor charged when the percentage would produce less. It makes low-priced items disproportionately expensive to sell through the marketplace, which is why very cheap products generally do not work on FBA without bundling.
Should I use the professional or individual plan?
Divide the monthly subscription by the per-item fee to find the break-even unit count. Above it the professional plan is cheaper, and it also unlocks features that matter for serious selling. Below it the per-item plan is the rational choice.
What margin do I need to make FBA work?
Materially more than for an own store, because the fee stack commonly consumes a quarter to two-fifths of the sale price before advertising. A product with a modest gross margin will not survive the arithmetic no matter how well it sells.
Are advertising costs really unavoidable?
On any competitive listing, effectively yes. Organic placement on a crowded search result is difficult to achieve and harder to hold, so sponsored placement functions as a cost of doing business rather than an optional growth lever.
How do returns affect FBA economics?
Substantially. Amazon's returns policy is generous by design, some categories carry a returns processing fee, and returned units may be unsellable. Build a returns allowance into your margin rather than discovering it in a quarterly reconciliation.