Free Amazon seller tool · USD
FBA fee change calculator
Short answer
Subtract the old fee from the new fee and multiply by monthly units sold to estimate the monthly impact. A change from $3.22 to $4.71 at 600 units adds $894 a month, or $10,728 annualized. These are entered scenarios; check actual charged fees before investigating an error.
Calculate the fee change
USD only. Enter fees to the cent and a whole number of units. Inputs stay in this browser tab; no signup required.
Impact at your entered fees
Submit your scenario to see its impact. The starting values are an example.
How the calculation works
| Output | Formula |
|---|---|
| Per-unit fee change | new fee − old fee |
| Monthly cost change | per-unit change × monthly units |
| Annualized cost change | monthly change × 12 |
| Margin change (percentage points) | −per-unit fee change ÷ selling price × 100 |
For $3.22 → $4.71 and 600 units, the increase is $1.49 per unit, $894 per month and $10,728 annualized. At a $20 selling price, margin falls 7.45 percentage points if every other cost stays the same. Reversing those fees produces savings at the same volume.
Annualized impact assumes constant volume and fees for twelve months. This is not a sales forecast. Zero monthly units gives zero monthly and annual impact. An old fee of zero still gives a dollar difference; a relative percentage increase from zero is undefined.
What this does not do
This calculator does not calculate overall profit or profit margin: it has no cost of goods, advertising or other costs. The optional margin result isolates the effect of this one fee change.
Check the charges before investigating an error
Use comparable old and new amounts for the same fee type, product, marketplace and currency. Estimates from an alert or fee preview may differ from actual charged fees. Compare your scenario with the transaction charges and their dates in Seller Central.
An increase alone does not prove a measurement error, category change or right to reimbursement. Rate updates, price changes and packaging changes can also affect fees. Review the relevant evidence before requesting a correction.
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