What this site is for
CalcRabbit started with a reseller's problem. Every marketplace publishes its fees, but none of them show you what a sale actually leaves in your pocket once shipping, sales tax, promoted listings and the payment processor have all taken their cut. Working that out by hand for every listing is tedious, and most of the calculators online either round in the wrong place or quietly use last year's rates.
So we built calculators that do it properly, and then kept going: mortgages, refinancing, paychecks, freelance tax, and the everyday sums like sales tax, paint and concrete. Every one answers a single question, shows the formula it used, walks through a real example, and links to where its numbers came from.
How the calculators are built
- Money is never a floating-point number. Every calculation runs in exact decimal arithmetic and rounds to the cent at the same step the platform does, so eBay's $0.40 per-order fee and Poshmark's $2.95 flat fee come out the way they appear on a real statement.
- Every calculator exists twice. The page is rendered on our server with the answer already worked out, then recalculates in your browser as you type. The two implementations are written separately and run against the same set of test cases before anything is published. If they ever disagree, the site doesn't build.
- Rates are dated facts. Fee schedules and tax tables live in one place with the date they took effect, the date we last checked them, and a link to the platform's own page. That date is printed on every calculator that uses them.
- The page works without JavaScript. You get the full answer, the breakdown, the example and the FAQ before a single script loads.
Where the rates come from
Directly from the source: eBay's, Mercari's, Poshmark's, Depop's, Etsy's, PayPal's and Stripe's published fee pages, the IRS for federal brackets and the Social Security wage base, and state revenue departments for sales tax. When a platform changes a fee we update the table, bump the checked date, and the change flows through to every calculator and guide that uses it. If you spot one we've missed, the contact form is the fastest way to tell us.
What we don't do
We don't give financial, tax or medical advice; the calculators show you the arithmetic, and the decisions are yours. We don't sell your data, we don't run affiliate links, and we don't ask you to sign up for anything. The site is supported by advertising, which is described in the privacy policy.
Who's behind it
CalcRabbit is made by a small team with a background in software and online selling. We're based in the United States and the site is written for US rates and rules. Guides are written by us, checked against the sources they cite, and dated so you can see when they were last reviewed.
Questions, corrections and requests: info@calcrabbit.com, or the contact page.