Seller Fee & Profit Calculator

Sell online? Work out the price that actually leaves you the money you wanted.

MarginBase is a fee, margin and break-even calculator for people who sell online — resellers, makers and small shop owners. Type in a few numbers, get the answer straight away, and get back to selling. No accounts, no sign-in, no setup.

PRICE IT SO THE FEES DO NOT EAT YOUR PROFIT

Every marketplace takes a cut: a percentage of the order plus a flat charge per sale. Most calculators tell you what is left after the cut. This one works backwards. Tell it what you want to keep and the fee rate you pay, and it gives you the price to list at — the exact price that leaves your target amount in your pocket once the fees come off.

Rates differ by marketplace, by category and by country, and they change. So you type in the percentage fee and the flat fee you actually pay. That means the maths fits wherever you sell, and it keeps working when the rate card changes.

FIVE CALCULATORS SELLERS ACTUALLY USE

- Fee-adjusted price. Enter the amount you want to keep, the percentage fee and the flat fee per order. Get the price to list at.
- Selling price. Enter your cost and the margin or markup you want. Get the price to charge.
- Margin and markup. Enter cost and selling price, see margin % and markup % side by side — the two numbers sellers mix up most, and the mix-up that quietly eats a listing's profit.
- Break-even. Enter fixed costs, price per unit and cost per unit, see how many units and how much revenue you need before you are in profit.
- Monthly cash check. Enter cash on hand, money coming in and money going out, see your projected end-of-month balance.

WHO IT IS FOR

- Resellers and flippers pricing thrift, clearance and wholesale finds.
- Makers and handmade sellers pricing materials, hours and craft-fair stock.
- People selling on marketplaces such as Etsy, eBay, Poshmark, Mercari, Depop or Vinted, and on their own Shopify store: enter the rate that marketplace charges you and price accordingly.
- Small shops and print-on-demand sellers checking a price survives payment processing.
- Anyone who has sold something and found the payout smaller than expected.

BUILT FOR SPEED ON A PHONE

- Plain-language answers, no finance jargon.
- One-handed, portrait-first, numeric keypad input.
- Your recent inputs are kept per calculator, on the device.
- Exact decimal maths, so the number you see is the number you get.

FULLY OFFLINE, FULLY YOURS

- Works completely offline after install. No internet is ever required, so it works in a basement thrift store with no signal.
- No account and no sign-in.
- Everything stays on your device. There is no cloud sync and there are no servers.

A SIMPLE PAID APP

- One-time purchase. Install it and the whole product is yours.
- No subscriptions, no ads, no in-app purchases, no locked "premium" features.

WHAT IT IS NOT

MarginBase is a small, sharp calculator with deliberately limited ambition. It is not a finance platform, not accounting software, not a collaboration tool, not a subscription service, and not an all-in-one business app. It does not do bookkeeping, invoicing, tax, inventory, forecasting or reporting, and it does not connect to your shop or read your orders. It does one job well: the pricing, margin and break-even maths behind every sale.

MarginBase is an independent app. It is not affiliated with, endorsed by or sponsored by any marketplace, and all trademarks belong to their respective owners. Fee rates change, so always enter the rate your marketplace currently charges you.