Amazon FBA Profit Calculator
Amazon takes a referral fee, a fulfilment fee, storage, and sometimes a returns processing fee. This calculator puts all of them on one line so you can see the unit economics before you buy inventory.
| Line item | Amount |
|---|---|
| Sale price | — |
| Referral fee | — |
| FBA fulfilment fee | — |
| Storage | — |
| Inbound freight | — |
| Product cost | — |
| Ad spend | — |
| Profit per unit | — |
Why FBA margins collapse after the first year
The mistake almost every new seller makes is calculating margin as price minus product cost minus referral fee. That figure looks wonderful — often 50% or more — and it is wrong by roughly half.
Four costs sit between gross and net, and three of them are invisible at the sourcing stage:
| Cost | Typical share of price | When it hits |
|---|---|---|
| Referral fee | 15% | Every sale, instantly |
| FBA fulfilment | 10–20% | Every sale, instantly |
| Inbound freight | 3–8% | At purchase, per unit |
| Storage | 1–3% | Monthly while it sits |
| Advertising | 10–25% | Until organic rank builds |
| Returns | 2–8% | Unpredictably |
Add them up and a product with a 50% gross margin lands at 10–20% net. That is why the same product can be a business for one seller and a slow bleed for another — the difference is whether they modelled the last four lines before buying inventory.
What the numbers should look like
20–30% net margin is the healthy band for a private-label product. Below 15%, you have no buffer for a Q4 storage surcharge, a competitor undercutting you by 20%, or a return spike. Above 35% is unusual and often means you under-invested in advertising — the sales will not sustain themselves.
A second check that matters more than margin percentage: absolute profit per unit. A 25% margin on a $12 product is $3. One return, one ad click overspend, and the unit is gone. Many experienced sellers will not touch a product under $5 profit per unit no matter how attractive the percentage looks.
How to use this before you order inventory
Run three scenarios: pessimistic, base case, and a 20%-off promo. If the pessimistic case is negative, the product is too thin. If only the optimistic case works, you are betting on everything going right — and with FBA storage fees peaking in Q4 and returns clustering after Christmas, everything rarely goes right.
Frequently asked questions
Is the referral fee charged before or after the fulfilment fee?
They are independent. The referral fee is a percentage of the sale price; the fulfilment fee is a flat charge by size and weight tier. Both are deducted from your disbursement.
Why is my calculator result different from Seller Central?
Fulfilment fees depend on exact packaged dimensions and weight, which Amazon measures itself. If your product is near a size-tier boundary, use Seller Central's Revenue Calculator with your real measurements — a half-inch can move you into a higher fee bracket.
Should I include ad spend here?
Yes, if you are running PPC. Divide total monthly ad spend by units sold and enter it per unit. Excluding it is the single most common way sellers convince themselves a losing product is profitable.
Do these rates stay the same?
No. Amazon revises referral schedules and fulfilment fees regularly, and adds seasonal storage surcharges in Q4. Always confirm current rates in Seller Central before committing to a purchase order.
Last reviewed: October 2026. Fulfilment fees vary by size tier and are set by Amazon; enter your actual quoted fee for accuracy.