Ecommerce Profit Calculator — Find Your True Profit Per Sale

Name: Ecommerce Profit Calculator
Author: James Blanckenberg

Last reviewed: 17 May 2026

True per-unit profit after platform fees, shipping, ad spend, and tax. Presets for Amazon FBA, Etsy, eBay and Shopify.

Ecommerce profit per unit = Selling Price − Product Cost − Platform Fee − Shipping − Ad Spend − VAT. On a $29.99 Amazon FBA sale with $8 product cost, 15% platform fee, $3.50 shipping, and $2 ads, you net about $12. Most sellers underestimate platform fees and ad spend.

How it works

Pick the platform you sell on — fee percentage pre-fills. Enter your selling price, product cost, shipping cost, and advertising cost per sale. For UK and SA, VAT is removed from the gross selling price first. What's left after all deductions is what actually reaches your bank account per unit sold.

Common mistakes

Treating VAT as revenue — UK and SA sellers show prices inclusive of VAT, so the gross deposit from a marketplace looks larger than the actual sale. VAT goes to HMRC or SARS, not into your bank balance. Strip it out before subtracting fees, or per-unit profit will be overstated by 13–17%.
Ignoring returns and refunds — apparel and electronics can see return rates of 15–30%, and a returned item forfeits the platform fee, the shipping out, and usually the ad spend that won the sale. Profitability calculated on shipped units overstates true take-home; build a return allowance into shipping or ACOS to model the real economics.
Spending on ads without tracking per-unit ACOS — total monthly ad spend tells you nothing about whether each sale is profitable. Track advertising cost per sold unit (ACOS). A $30 product with a $9 ad cost (30% ACOS) and a 40% gross margin only nets $3 after fees and shipping — paid traffic at that level is unsustainable.

When to use this calculator

Use this for every new SKU on Amazon FBA, Etsy, eBay, or Shopify before you list it, and re-run quarterly as platform fees and ad costs drift up. It is built specifically for marketplace sellers who pay variable platform fees, shipping, and ad costs that do not appear on a standard income statement.

If you are not a marketplace seller and want a simple gross/net margin view, the Profit Margin Calculator is faster. If you are setting the selling price from scratch with a target margin in mind, start with the Pricing Calculator and then audit the result here.

See the formula

Net Profit = Selling Price − Product Cost − Platform Fee − Shipping − Ad Spend − VAT

Platform Fee = Selling Price × (Platform Fee % / 100)

Example: $29.99 sale | $8 cost | 15% fee | $3.50 shipping | $2 ads
  Platform Fee = $4.50
  Net Profit   = $29.99 − $8 − $4.50 − $3.50 − $2 = $11.99
  Net Margin   = 40%

Worked example

A US Amazon FBA seller lists a kitchen product at $29.99. Landed product cost (including freight from the supplier and inbound shipping to an Amazon warehouse) is $8.00. Amazon's FBA fulfilment fee for the size tier is $4.50. The 15% referral fee comes to $4.50. Sponsored-product PPC averaged out across recent sales runs at $3.00 per unit sold (a 10% ACoS). A reserve for returns and damages adds $1.50, and the variable shipping back to customers in edge cases averages $0.80.

Adding all costs: $8.00 + $4.50 + $4.50 + $3.00 + $1.50 + $0.80 = $22.30. True per-unit profit is $29.99 − $22.30 = $7.69 — a 25.6% net margin. The seller's naive maths (price minus product cost) suggested $21.99 of profit per unit and 73% margin. The $14.30 of platform-and-fulfilment costs is the gap most Amazon sellers miss until they run a complete profit calculation.

The two biggest levers are PPC and return rates. Cutting PPC from $3.00 to $2.00 per sale (an 8% ACoS instead of 10%) lifts net profit to $8.69 — a 13% per-unit profit increase from a single metric. Reducing the return reserve from $1.50 to $0.50 by fixing a product-defect cluster does the same. Both levers are usually within the seller's control; the FBA fee and referral fee are not.

Frequently Asked Questions

Why is my ecommerce profit lower than I expected?

Most sellers underestimate their true costs. Platform fees (10–20%), shipping (10–25% of revenue), advertising (10–30%), and payment processing all erode your margin. This calculator adds all these up — the result is often a shock for sellers who only calculated product cost vs. selling price.

What are Amazon FBA fees?

Amazon FBA (Fulfilled by Amazon) charges a referral fee (typically 8–15% depending on category) plus fulfilment fees based on product size/weight (typically $3–$8 per unit). There are also monthly storage fees. Enter your total fee as a percentage of selling price in this calculator.

How do I calculate Etsy profit?

Etsy charges a 6.5% transaction fee, a payment processing fee (3–4%), and a listing fee ($0.20 per item). Enter 6.5% as the platform fee and add the listing fee to your fixed costs. Etsy also collects VAT in the UK and SA on your behalf.

What profit margin should I target in ecommerce?

Target a minimum net profit margin of 20–30% per unit after all fees and costs. Below 15% leaves no room for returns, price competition, or ad spend increases. Below 10% is generally not viable as a sustainable ecommerce business.

How does advertising cost affect ecommerce profitability?

Advertising cost per sale (also called ACOS — Advertising Cost of Sale on Amazon) directly reduces your net profit. An ACOS of 30% on a $30 product means you spend $9 in ads per sale. Tracking ad spend per unit sold (not total campaign spend) is essential for accurate profitability analysis.

How does VAT change my ecommerce profit in the UK and SA?

If you are VAT-registered, the gross selling price is shown inclusive of 20% VAT in the UK or 15% in South Africa. You owe that VAT to HMRC or SARS, so it never reaches your bank account. The calculator strips it out before calculating profit. In the US, sales tax is collected at checkout and remitted to the state — also not your money. Always work in net-of-tax numbers when comparing per-unit profitability.

What is the biggest mistake new ecommerce sellers make on profit?

Pricing based on product cost alone and ignoring variable costs per sale. A $20 product that cost $8 looks like a 60% margin — until you subtract a $3 platform fee, $4 shipping, $3 ad spend, and $0.60 in payment processing. Real net profit is $1.40, or 7%. Run every product through this calculator before launching, and re-run quarterly as fees and ad costs change.

What if I have returns or refunds — how do I factor those in?

Returns are usually expressed as a percentage of orders (5–15% is typical, higher in apparel). To bake them in, increase your platform fee or shipping cost slightly to reflect the real cost per sold-and-kept unit. For example, a 10% return rate on a product that costs $4 to ship adds about $0.40 in absorbed shipping per net sale. Returns also forfeit the original ad spend, so add a small premium to ACOS too.

What if my advertising cost per sale is zero?

That means you are getting all your traffic from organic, repeat, or referral sources — the most profitable kind of revenue. The calculator will return a higher net profit, which is correct, but be cautious about assuming this can scale. Most ecommerce businesses need paid ads to grow beyond their existing audience. Model the same product with a realistic ACOS (20–30%) to see what scaled economics look like.

How is ecommerce profit different from a regular profit margin calculation?

A regular profit margin treats cost as a single COGS line. Ecommerce profit breaks variable costs into four moving parts — product cost, platform fee, shipping, and ads — because each one behaves differently. Platform fees scale with price, shipping scales with weight, and ad cost scales with competition. Treating them separately exposes which lever to pull when margin slips, instead of just "costs are up."

Glossary

Platform Fee: The marketplace cut taken on each sale. Amazon referral fees are typically 15%; Etsy charges 6.5% transaction plus listing and payment fees; eBay sits around 12-15%.
ACoS: Advertising cost of sale — ad spend divided by ad-attributed revenue. The per-unit ad cost that has to come out of gross margin before it becomes profit.
FBA: Fulfilment by Amazon — Amazon stores, picks, packs and ships your inventory in exchange for a per-unit fulfilment fee based on size and weight.
Landed Cost: The all-in product cost including supplier price, inbound freight, duties, and inspection. The right number to use in this calculator, not the supplier invoice alone.

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Methodology & sources

Rates last verified: May 2026

Read the full methodology →

Platform fee defaults: Amazon FBA 15%, Etsy 6.5%, eBay 13%, Shopify 2.9%. Headline rates only — your actual fees may include category-specific premiums or volume discounts. Check your platform's seller dashboard for the exact split.

Primary sources

Rates are reviewed annually or when a region changes its headline rate. If you spot one that's out of date, email [email protected].

For information only. This calculator does not constitute financial, accounting, or tax advice. Consult a qualified professional before making business decisions.

Try these scenarios

Pre-filled examples — click any chip to load the inputs and result.

How to calculate ecommerce profit per unit

Pick your platformClick Amazon FBA, Etsy, eBay, Shopify, or Custom — the platform fee % pre-fills accordingly.
Enter selling price and product costYour listing price and the landed cost of the product to you (including shipping into your warehouse).
Add shipping and ad spend per saleOutbound shipping cost (if you cover it) and the advertising cost attributable to each sale.
Set the VAT rate (optional, UK/SA)VAT is removed from the gross price for VAT-registered sellers in UK and SA.
Read net profit and net margin per unitThe result shows what actually reaches your bank after every deduction.

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Written by

James Blanckenberg

Founder, BusCalcTools

Founder of BusCalcTools and FinnCalc. Builds practical financial calculators for small business owners and freelancers across the US, UK, and South Africa.

Editorial review by: James Blanckenberg, Founder & Editor

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