About
SellerTools
SellerTools provides free ecommerce calculators to help sellers understand the numbers behind their business — profit, margins, platform fees, and advertising performance — before they commit money to inventory or ads.
What we do in one sentence
We build free, instant calculators that show ecommerce sellers exactly what they keep on every sale — after every fee, cost, and deduction — so they can make decisions based on real numbers, not assumptions.
The problem we're trying to solve
Most sellers launch products without understanding true profitability. SellerTools aims to fix that.
Every day, ecommerce sellers make expensive decisions based on incomplete numbers. They see a product cost of $12 and a selling price of $40 and assume they're making $28 per sale. They're not.
By the time you add the platform fee (2–15% depending on the channel), the payment processing fee (another 2–3%), the shipping cost, the return rate, and the cost to acquire the customer through ads — that $28 can become $6. Or zero. Or negative.
This isn't a rare edge case. It's how most products actually perform once all costs are factored in. The sellers who scale are the ones who know their numbers in advance and price accordingly. The ones who struggle are doing the maths wrong, or not doing it at all.
SellerTools exists to close that gap. Every calculator on the site is built to answer one specific question that a real seller needs to answer before they spend money — and to answer it in under a minute, with no spreadsheet, no signup, and no guesswork.
"The sellers who scale are the ones who treat $28 gross profit and $28 net profit as completely different numbers — because they are. Our tools make that distinction impossible to miss."
Built for every type of ecommerce seller
Whether you're sourcing products to resell, building a brand, selling on a marketplace, or scaling with paid ads — the fundamental problem is the same: you need to know what you actually keep.
Dropshippers
You're testing products fast and the margins are tight by default. The difference between a winner and a money pit is often less than $5 per sale — but only if you're counting every cost. Platform fees, payment fees, ad spend per conversion, and return rates all cut into what looks like a healthy gross margin.
Ecommerce brands
You've built a product and a price point. Now you need to know what margin that leaves before you commit to ad spend, hire fulfilment staff, or pitch to a retailer. Gross margin is a starting point — net margin is the number that determines whether the business model actually works.
Marketplace sellers
eBay, Amazon, and Etsy each have their own fee structures — and each one takes a bigger slice than most sellers expect. An item that's profitable on one platform can be marginal on another. Knowing the exact fee load for each channel before you list is the difference between growth and churn.
Advertisers running paid ads
ROAS is not profit. A 4× ROAS on a low-margin product can still mean you're losing money on every sale. Before you set a Target ROAS or a CPA bid in Meta, Google, or TikTok, you need to know the minimum ROAS your product economics can sustain — and how much room you have above that floor.
Making ecommerce numbers transparent
The goal is to make accurate profit calculations accessible to every seller, regardless of where they are in building their business.
Ecommerce has a numbers problem. Platforms have every incentive to make their fee structures complex and hard to calculate in advance. Sellers often discover the true cost of a channel only after they've already listed, advertised, and sold — by which point changing course is expensive.
SellerTools exists to shift that balance. Every tool is free, requires no account, and stores nothing. All calculations run entirely in your browser. Your product costs and margins are your business — they stay on your device.
The aim is simple: if a seller can spend five minutes with one of these calculators before sourcing a product or launching an ad campaign, they'll make a more informed decision. Over thousands of sellers, that adds up to less wasted money and better businesses.
No paywalls, ever
Every calculation, every feature, every result is available without a free trial, a credit card, or an upgrade prompt. The tools work fully the first time you open them and the thousandth.
No data collected
Nothing you type into these calculators is sent to a server or stored anywhere. Your product costs, margins, and ad data are private by design. The URL share feature works by encoding your numbers in the link itself — not on our servers.
Speed over complexity
Each tool is designed to answer one question clearly and quickly. There are no multi-step wizards, no onboarding flows, no dashboards. You open the page, enter your numbers, and get an answer in under a minute.
Built for decisions, not reports
The goal of every calculator is to help you make a specific decision: should I sell this product? Is this margin scalable with ads? What's the maximum I can pay per click? Numbers for the sake of numbers aren't useful — numbers that drive action are.
Works everywhere you work
Fully responsive on mobile, tablet, and desktop. Built to be used at a trade show, in a supplier meeting, in a warehouse, or at a desk. Every shareable link loads identically regardless of device.
Share any scenario
Every set of inputs generates a unique URL. Send it to a supplier, business partner, or accountant — they'll see exactly what you're looking at, with the same numbers, on any device, with no account required.
See your real profit in under a minute
Pick a calculator, enter your details, and get exact profit, margin, fees, and ad targets — instantly and for free.