How we calculate
No black box: here are the formulas, an example you can recalculate, where our fee and tax numbers come from, and what we do not know.
The formulas
The Shop-Check and all profit calculators use the same calculation engine. Everything is per order, with one unit per order.
- Net price
gross price ÷ (1 + VAT rate)- Expected net revenue
net price × (1 − return rate)- Product cost
purchase price × (1 − return rate)- Fees
fee % × gross price + fixed fee- Return cost
cost per return × return rate- Contribution
expected net revenue − all costs- Margin
contribution ÷ expected net revenue- Break-even price
price-independent costs ÷ ((1 − return rate) ÷ (1 + VAT) − fee %)- Price for target margin m
price-independent costs ÷ ((1 − return rate) × (1 − m) ÷ (1 + VAT) − fee %)
The Shop-Check feeds your typical product into exactly these formulas. Monthly values are the result per order × your orders per month. If you leave the orders empty, we show no monthly values.
A worked example
These are the default values of the profit calculator. Open the calculator and you get the same numbers.
| Selling price (incl. 19% VAT) | €39.99 |
|---|---|
| Purchase price (net) | €12.00 |
| Shipping per order | €4.50 |
| Marketplace fee | 15% |
| Ad cost per order | €3.00 |
| Return rate · cost per return | 10% · €5.00 |
| Other costs | €0.50 |
| Price without VAT | €33.61 |
|---|---|
| Expected net revenue (after 10% returns) | €30.24 |
| All costs per order | €25.30 |
| Profit per order (contribution) | €4.95 |
| Margin | 16.4% |
| Break-even price (incl. VAT) | €31.83 |
| Price for a 25% margin (incl. VAT) | €46.26 |
Open this example in the calculator
Calculated or estimated?
- Calculated
- Follows exactly from your numbers, e.g. the profit per order or the break-even price.
- Estimated
- Needs an assumption that we state next to it – for example that you keep selling the same number of products after a price increase, or that your return rate halves.
- Not calculable
- When your numbers are not enough, we say so instead of guessing. We never invent a potential.
Where our numbers come from
Fees and tax rates come only from official pages. Each number carries the date we last checked it. Our tests fail if a platform fee was not checked for more than 90 days, so we have to look again.
Amazon Seller Profit Calculator
- Amazon – seller pricing (DE) (checked on October 21, 2026)
- Amazon – seller pricing (US) (checked on October 21, 2026)
E-commerce Profit Calculator
- business.gov.au – Goods and services tax (GST) (checked on October 20, 2026)
- Canada Revenue Agency – GST/HST rates (checked on October 20, 2026)
- CBIC (India) – GST rates (checked on October 20, 2026)
- European Commission – Taxes in Europe database (VAT rates of EU countries) (checked on October 20, 2026)
- GOV.UK – VAT rates (checked on October 20, 2026)
- Swiss Federal Tax Administration – VAT rates (checked on October 20, 2026)
Etsy Fee & Profit Calculator
- Etsy – Fees & Payments Policy (checked on October 21, 2026)
- Etsy Help – Fees (checked on October 21, 2026)
- Etsy Help – Offsite Ads (checked on October 21, 2026)
- Etsy Help – Payment processing fees (checked on October 21, 2026)
- Etsy Help – Regulatory operating fee (checked on October 21, 2026)
Product Feed Validator
- Google Merchant Center – GTIN [gtin] (checked on October 20, 2026)
- Google Merchant Center – Product data specification (checked on October 19, 2026)
ROAS & Break-even ROAS Calculator
- Google Ads Help – About Target ROAS bidding (checked on October 21, 2026)
Shopify Profit Calculator
- Shopify – official pricing (AT) (checked on October 21, 2026)
- Shopify – official pricing (DE) (checked on October 21, 2026)
- Shopify – official pricing (GB) (checked on October 21, 2026)
What happens with your numbers and files
- Calculators and the Shop-Check calculate in your browser. We do not store your numbers. If you share a result link, the numbers are part of that link.
- Catalogue and feed files are read and analysed in your browser. The file content never reaches our server.
- To unlock a paid analysis, your browser only asks our server whether you have access and books one credit. For the feed check it also sends a short fingerprint of the file (a hash), so the same file is not charged twice. The fingerprint cannot be turned back into the file.
- The catalogue analysis may keep the file in this browser tab (up to about 1.5 million characters) so a reload does not lose your work. It is gone when you close the tab.
- Only if you sign in and save a Shop-Check plan do we store that plan (the numbers of the plan link) on our server, so you can open it again.
Limits
- The results are estimates based on your numbers. They are only as good as the numbers you enter.
- This is not tax or legal advice. VAT rules have many special cases (e.g. reduced rates, distance sales, small businesses). For your situation, ask a tax adviser.
- Platform fees change. Check the date next to each source and compare with your own invoices.
Found a mistake in a formula or a number? Tell us via the feedback link in the footer – we fix it and update the date.