About

About Flip Profit HQ

A small, independent business that makes reseller fee calculators, a profit sheet and an offline app. This page explains how the numbers are made and checked, so you don’t have to take them on faith.

Fees last checked November 9, 2026

Who we are

Flip Profit HQ is a small independent team. We are not affiliated with, endorsed by or sponsored by Whatnot, eBay, Poshmark, Mercari, Depop, Etsy, Meta or any other marketplace. Their names appear only to describe which fees and sales reports our tools work with.

We don’t put names or faces on the site. Instead, we show our work: every fee rule, its official source and the date we checked it are public on the Fee Ledger, every change is dated on the changelog, and you can email us about anything.

The site and the free calculators went live on October 6, 2026, along with Pro. To hear from real sellers early, we’re giving 10 Pro licenses to founding testers in exchange for honest feedback.

What the tools do

  • Free fee calculators for Whatnot, eBay, Poshmark, Mercari, Depop and Etsy, plus a side-by-side comparison. Enter a sale and see the estimated fees and what you keep. No sign-up.
  • The Core sheet ($29): a Google Sheet that runs the same fee rules on every sale you log or import, then takes out shipping, supplies and what you paid.
  • Pro ($49): the Pro sheet plus the Flip Profit HQ app, which works offline and installs on your phone, with tools for pricing, sourcing, listings, grading, shows, returns and year-end records.

It’s record-keeping, not tax advice. Nothing logs into, scrapes or automates any marketplace; imports only read report files you download yourself.

How fees are calculated and checked

  1. One fee table. Standard US seller fee rules for Whatnot, eBay, Poshmark, Mercari, Depop, Etsy, Facebook Marketplace, TCGplayer, Vinted and TikTok Shop live in one data file. Each rule records its official source page and a confidence level: high means we read it on the platform’s own help page; medium means an official source we couldn’t read in full. The Fee Ledger publishes all of it.
  2. One engine. A single fee engine turns that table into numbers. Every fee amount on this site, on the calculators, the answer pages, the examples and the free widget, is computed by that engine from the table when the site is built. None is typed in by hand. The app uses the same engine as you type.
  3. Hand-checked tests. The engine has automated tests whose expected results were worked out by hand from the published rules, with the arithmetic written next to each case so it can be re-checked.
  4. Official sources first. Fee rules are checked against each marketplace’s official help pages. The last full re-check of every platform was October 4, 2026; the dates each source page was updated are on the Fee Ledger.
  5. A fee-change watch, twice a week. Every Monday and Thursday, a scheduled check compares each platform’s official fee pages, and recent fee news, with our fee table. If something changed, it’s reviewed against the official page before the table is updated; then the calculators, the sheets and the Fee Ledger change together and the change is dated on the changelog. Last check: November 9, 2026.
  6. How it’s built. AI tools helped write the code for this site, the sheet’s formulas and the app. That’s why the tests above exist: the numbers are checked against hand-worked examples rather than trusted because the code produced them. Formulas in the sheet stay unlocked, so you can check the math yourself.

Limits. The calculators use standard US seller rates. Store subscriptions, promotions, ads, sales tiers, payment methods, state taxes on fees and account-specific rules can change your real fees. Treat every number as an estimate and confirm on the platform’s official fee page before relying on it.

Your data

  • Calculators: they run in your browser. What you type isn’t sent to us or stored.
  • The app: local-first. There’s no account; your records stay in your browser’s storage on your own device, and we keep no copy. Backups are files you download and keep. Activating a Pro license sends only the key and a random device ID.
  • The sheet: your copy lives in your own Google Drive. We can’t see it.
  • Email: if you join the list, we use your email for Flip Profit HQ updates and never sell it.

The full details are in the privacy policy.

The wrong-fee promise

If a fee in our calculators, sheet or app is wrong, tell us with a link to the platform’s official fee page. If you’re right, we fix it, update the Fee Ledger and add a dated line to the changelog. If you bought the sheet or Pro and would rather have your money back, we’ll refund you.

Contact

Support: flipprofithq@gmail.com

Request a calculator Report a wrong fee

Flip Profit HQ is independent and not affiliated with any marketplace. Fee rates are estimates based on publicly available information checked on the dates shown. Not tax, legal or financial advice.