eBay Seller Fee Calculator

WHAT IT DOES

eBay Seller Fee Calculator automatically detects the item price on any eBay listing page and calculates the estimated seller fees you would pay when selling that item. The tool breaks down the final value fee (based on category and store tier), insertion fee, and promoted listing fee, then shows the total fees, net profit, and profit margin. This helps sellers quickly evaluate whether a listing is worth creating, compare profit margins across different items, and make informed pricing decisions before listing items for sale.

WHERE IT RUNS

This extension works on eBay at www.ebay.com. It functions on item listing pages, including the main listing view, bid pages, and buy-it-now listings. The tool automatically detects the item price regardless of where it appears on the page and adapts to eBay's various listing layouts.

HOW TO USE

Install the extension and navigate to any eBay item listing. The tool automatically detects the item price and displays a fee breakdown in the overlay panel. Customize the fee calculation by adjusting the Final Value Fee percentage (default 13.6%), Insertion Fee (default $0.35), Promoted Listing Fee percentage (default 5%), and selecting your Store Subscription tier (No Store, Basic, Premium, or Anchor) — each tier applies a discount to the final value fee. Click "Calculate Fees" to refresh the calculation after changing settings or viewing a new item. The results show a detailed breakdown including the item price, each fee component, total fees, net profit, and profit margin percentage.

TECHNICAL SECTION — FEE CALCULATION ENGINE

The extension extracts the item price using a multi-selector strategy that targets eBay's price display elements including .ux-price, .vi-price, #prcIsum, and itemprop="price". It also handles currency formatting by removing commas and dollar signs. The fee calculation engine applies the configured final value fee percentage (adjustable by category) and store discount based on the selected subscription tier. Category detection uses breadcrumb navigation to identify the item's category and applies category-specific fee adjustments — for example, electronics (10%), clothing (12%), and collectibles (14%). The promoted listing fee is calculated as a percentage of the item price, and the insertion fee is added as a fixed cost. The net profit is calculated as price minus total fees, and the profit margin is expressed as a percentage of the price.

THE PANEL — DRAG / PER-SITE POSITION / SNAP / COLLAPSE / RESIZE / ESCAPE

The overlay panel is fully interactive and designed for seamless multitasking. Drag it anywhere on the screen using the handle at the top of the panel; the position is saved per site so it stays where you left it across sessions. The panel includes a snap-to-edge feature that gently anchors the overlay to the nearest screen edge when released. Click the collapse button to minimize the panel to a compact pill showing the current profit estimate; expand it again with a single click. Resize the panel vertically by dragging the bottom-right corner to view more controls. Press the Escape key at any time to instantly close the overlay; it reappears on the next page navigation or refresh.

PLEASE NOTE

This extension requires the free BotGentz companion extension to function, as it provides the underlying content script injection and cross-origin communication framework. No personal data, browsing history, or eBay data is stored, transmitted, or shared. Settings are stored locally in your browser using GM_setValue and are never sent to any external server. The extension does not access or store login credentials, financial data, or personally identifiable information. The fee calculations are estimates based on publicly available eBay fee information and may not reflect your actual fees due to promotions, category-specific variations, or changes in eBay's fee structure. The tool does not account for shipping fees, taxes, or other costs associated with selling. Always verify fees on eBay's official fee pages before listing items.