Seller Fees Calculator

io.github.NarwhalThePongPublished by GitHub account NarwhalThePongv1.0.1Updated Oct 29, 2026

Gumroad, Stripe, PayPal and Etsy seller fees, payouts and break-even prices. Local, no API key.

The publisher's own server: Calculator Tools MCP

VerifiedSTDIODesktop onlyFinanceBusiness & Commerce

Overview

AI-generated overview

Local MCP server that calculates seller fees, payouts and break-even prices for Gumroad, Stripe, PayPal and Etsy (US sellers, USD).

What you can do
  • Calculate fees and net proceeds for a single sale on Gumroad, Stripe, PayPal or Etsy, with platform-specific options such as Discover, high volume, card processing, international, quantity, shipping, sales tax and offsite ads
  • Work out what you keep per sale and in total across a given number of units
  • Find the lowest price that still leaves a target amount after fees
  • Compare one price across Gumroad direct, Gumroad Discover, Stripe, PayPal and Etsy, ranked by best net
  • Look up default rates, available options and official source pages per platform
When to use it
Useful when you sell digital or physical products through Gumroad, Stripe, PayPal or Etsy and want quick fee, payout or break-even estimates while planning prices, without leaving the assistant.
Requirements
Runs as a local process via npx or from source; requires Node.js 18 or newer. No API key, account or network access is needed.
Before you install
Figures are planning estimates only, not tax or accounting advice, and default rates are dated, so verify against each platform's current pricing page. The README discloses that the author also sells related paid products (a browser extension and a Google Sheets add-on) and links to them.

Installation

In SourceWeft

  1. Open Seller Fees Calculator in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

seller-fees-mcp

A free Model Context Protocol (MCP) server that works out seller fees, payouts and break-even prices for Gumroad, Stripe, PayPal and Etsy (US sellers, USD). Everything runs locally: no API key, no account, no network calls.

Tools

ToolWhat it does
feeFee and net for one sale. Gumroad direct includes the 2.9% + $0.30 card processing; options discover, high_volume, processing (card/none). PayPal type and international, Stripe extra_pct, Etsy qty, shipping, sales_tax_pct, offsite_ads.
payoutWhat you keep per sale and in total for units sales.
price_for_targetLowest price that leaves at least target after fees.
compareOne price across Gumroad direct, Gumroad Discover, Stripe, PayPal (checkout, card, goods) and Etsy, best net first.
platformsDefault rates, options and official source pages.

Default rates are as of Oct 20, 2026. Gumroad direct: 10% + $0.50 plus card processing 2.9% + $0.30 (5% + $0.50 with high_volume); Discover: 30% all-in. Stripe: 2.9% + $0.30. PayPal Checkout: 3.49% + $0.49. Etsy: $0.20 listing, 6.5% transaction, 3% + $0.25 processing. Check each platform's pricing page before relying on a number. Planning estimates only; not tax or accounting advice.

Install

Requires Node.js 18 or newer.

npx

bash
npx -y seller-fees-mcp

From source

bash
git clone https://github.com/NarwhalThePong/seller-fees-mcp.git && cd seller-fees-mcp && npm install && npm testnode src/server.js

Desktop MCP clients

Add to your client's MCP config file:

json
{  "mcpServers": {    "seller-fees": { "command": "npx", "args": ["-y", "seller-fees-mcp"] }  }}

Cursor

Add to ~/.cursor/mcp.json (or .cursor/mcp.json in a project):

json
{  "mcpServers": {    "seller-fees": { "command": "npx", "args": ["-y", "seller-fees-mcp"] }  }}

For a local checkout, use "command": "node", "args": ["/path/to/seller-fees-mcp/src/server.js"].

Example

fee with { "platform": "gumroad", "amount": 19 } returns a fee of $3.25 ($2.40 Gumroad + $0.85 card processing) and a net of $15.75.

Prefer a web page?

Disclosure: these are our own products. The calculator pages are free; Creator Payout Calculator Pro is a paid product we sell.

Prefer a spreadsheet?

Seller Fee Formulas for Google Sheets, $9: custom functions such as GUMROADFEE, STRIPEFEE, PAYPALFEE and ETSYFEE, plus price solvers for the price you need to keep a target amount, on a whole column at once. Our own paid product (the MCP server stays free).

License

MIT

Source: README.md at commit 6633a66

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v1.0.1LatestOct 29, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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