About this calculator
Adding a percentage to your cost to set a price ignores the fees that come out of every sale. This calculator works backwards: give it your cost, your fees and the margin you want to keep, and it tells you the price to charge, with and without VAT.
It works for online shops, marketplaces and anyone taking card payments. You enter your own fee rates, because platform fees change and yours may be different.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
£10 cost, 10% + 30p fees, 30% margin, 20% VAT
- Price to charge (before VAT)
- £17.17
- Price including VAT
- £20.60
- Fees you'll pay
- £2.02
- Your profit per sale
- £5.15
- Profit margin achieved
- 29.99%
Charging £17.17 before VAT (£20.60 with 20% VAT) covers a cost of £10.00 and £2.02 of fees, and leaves £5.15 profit.
The same, with fees charged on the VAT-inclusive price
- Price to charge (before VAT)
- £17.76
- Price including VAT
- £21.31
- Fees you'll pay
- £2.43
- Your profit per sale
- £5.33
- Profit margin achieved
- 30.01%
Charging £17.76 before VAT (£21.31 with 20% VAT) covers a cost of £10.00 and £2.43 of fees, and leaves £5.33 profit.
£50 cost, 20% margin, no fees, no VAT
- Price to charge (before VAT)
- £62.50
- Price including VAT
- £62.50
- Fees you'll pay
- £0.00
- Your profit per sale
- £12.50
- Profit margin achieved
- 20%
Charging £62.50 before VAT (£62.50 with 0% VAT) covers a cost of £50.00 and £0.00 of fees, and leaves £12.50 profit.
The formula
Every sale has to cover your cost, your fees and your profit, all out of the price:
Price = (cost + fixed fee) ÷ (1 − fee % − margin %)
With a £10 cost, a 30p fixed fee, 10% fees and a 30% margin: £10.30 ÷ (1 − 0.10 − 0.30) = £10.30 ÷ 0.60 = £17.17. The fees come to £2.02 and the profit is £5.15, which is 30% of the price. The price with 20% VAT is £20.60.
Why not just add up percentages to the cost?
Fees and margin are both shares of the price, not the cost. Adding 40% to a £10 cost gives £14, but 10% fees and a 30% margin of that price only leave 60% (£8.40) to cover a £10 cost. The cost is left short. Dividing by (1 − fee % − margin %) fixes this.
Fees on the VAT-inclusive price
Some platforms take their percentage from the total the customer pays, VAT included. That's a bigger fee on your VAT-free price: 10% of a VAT-inclusive total is really 12% of the price before VAT at a 20% rate. Choose “The price including VAT” above if that's how yours works. Check your platform's current fee terms, which this calculator deliberately doesn't hard-code because they change.
Frequently asked questions
How do I price a product to include fees?
Divide your cost plus any fixed fee by 1 minus the fee percentage minus the margin you want, all as decimals. The result is the price that leaves that margin after fees.
What's the difference between this and the profit margin calculator?
The margin calculator handles cost and price only. This one also takes marketplace or payment fees and VAT into account, which is what most sellers actually face.
Should I show customers the price with VAT?
That depends on your customers and the law. Many sellers to consumers must show prices including VAT. The calculator gives you both the price before VAT and the price including it.
What if I'm not VAT registered?
Choose the 0% rate. Then the price before VAT and the price the customer pays are the same.
Does this include postage?
Only if you add it to the cost. If you charge customers separately for delivery, leave it out. If you include free delivery in the price, add your postage cost to the product cost.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.