Most sellers price off one number: cost versus sale price. Buy at $62, sell at $189, that's a 40% margin — a good business.
Then the real costs arrive, one at a time and from different directions. Freight and duty on the way in. The processor's cut. A box, a label, and $12 of postage. The one-in-eleven order that comes back and can't be resold at full price. Forty dollars of ads to find the buyer in the first place. And a share of the rent, the software, and your own salary.
None of those show up in gross margin. All of them come out of the same $189. By the time they have, a business that looked like it kept 40% is keeping less than one percent — and it takes 250 orders a month just to cover the fixed costs.
Margin Desk does that arithmetic in one screen, so you find out before you've run the ads, not after.
Enter your figures once. Everything below recalculates as you type.
What lands in your pocket after every cost, including the fixed ones. Shown in dollars and as a margin, against the target you set.
Your break-even cost per order, and the break-even ROAS you have to beat. The two numbers to check before raising a budget.
Name a target margin and get the exact price that reaches it — plus the break-even price you must never go below.
A returned order earns nothing but still costs you postage, handling and the stock you can't resell. Priced in properly, not guessed at.
How many sales a month cover your fixed costs, and whether your current volume is clearing them or falling short.
Save a version, change a price or a supplier quote, save again. See what a five-dollar move does before you make it.
Fee presets for your own Shopify or WooCommerce store, Amazon, Etsy, eBay, Walmart Marketplace and TikTok Shop — every rate editable, because yours will differ.
Print a one-page summary with your own business name on it, or copy every figure straight into a spreadsheet. Useful for a partner, an accountant or a lender.
You receive a single web page. Save it anywhere — desktop, a shared drive, your own website. There's nothing to install and nothing to configure.
Double-click. It opens like a normal web page and runs entirely on your own machine, online or off. It works on a laptop, a tablet or a phone.
Your figures are remembered on your device between visits. Come back any time you change a supplier, a price or an ad budget.
Every calculation happens in your browser. Your costs, your suppliers and your margins are never sent anywhere, because there is no server to send them to. That also means no outage, no price rise, and no login to lose.
One number, one payment. Not another subscription competing with your ad budget.
No. There's no sign-up, no password and no recurring charge. You buy the file once and it's yours. Nothing expires and nothing phones home.
Nowhere. Every figure is worked out inside your browser, on your own machine. Your costs and margins are never transmitted, which is why the tool keeps working with the wi-fi off. Your last entry is saved on that device only, so opening it on a different computer starts fresh.
They're sensible starting points, not quotes. Real rates vary by category, country, plan and payment method, and the platforms change them. Every rate in the tool is editable, and the honest way to use it is to take the numbers off a recent payout statement — total fees divided by total sales — and type those in.
It's built around physical products sold online, where you buy or make a unit, ship it, and pay someone a cut. That covers most Shopify, Amazon, Etsy, eBay and WooCommerce sellers. If you sell digital goods or services, much of the model — freight, returns, fulfilment — won't apply.
Yes. Work out one product at a time and save each as a scenario to compare them side by side. It's built for going deep on the economics of a product, rather than importing a whole catalogue at once.
Say so and you'll get your money back — no argument and no form to fill in. You'll know within ten minutes of entering your own numbers whether it's telling you something you didn't already know.
Ten minutes with your own numbers is usually enough to change a price.
One-time payment · works offline · money back if it isn't for you
If Margin Desk isn't for you, email within 30 days of buying and you'll get a full refund. You don't need to give a reason and there's no form to fill in. Refunds are processed by Lemon Squeezy, who handle the payment, and land back on the card you paid with — usually within a few business days.
The calculator itself collects nothing. It runs entirely in your browser, stores your figures on your own device, and has no server to send anything to. This website sets no cookies and runs no analytics. When you buy, Lemon Squeezy acts as merchant of record and handles your payment details — we never see your card. We receive only your name, email address and what you bought, and we use that to deliver the file and answer support emails. Nothing is sold or shared.
The single business licence covers you and your own company — use it across every product and shop you own, on as many of your own devices as you like. The agency licence adds the right to use it in client work and to share the file with your team. Neither licence allows reselling it, giving it away, or publishing the file publicly.
Questions about any of this, or about a purchase: [email protected]. Emails are answered by a person, usually within a day.