Extensions / FBA Revenue Calculator

FBA Revenue Calculator privacy policy

Last updated: October 28, 2026

FBA Revenue Calculator is a Chrome extension that shows Amazon fees, profit, ROI and margin on product pages on amazon.com and amazon.co.uk. This policy explains exactly what it does with your data.

The short version

• No account, no analytics, no trackers and no cookies in the extension.
• Every calculation runs on your device, using Amazon's public fee tables built into the extension. The only network request downloads exchange rates. It is made only when Amazon shows prices in a currency other than US dollars on amazon.com or British pounds on amazon.co.uk, and it contains nothing but a currency code.
• On product pages on amazon.com and amazon.co.uk it reads only the product details it needs for the calculation. It reads nothing from other websites: when you click the icon there, it only checks the tab address to tell you the site is not supported.
• It does not change links on Amazon and does not add affiliate tags.

What the extension reads

On product pages (addresses with /dp/ or /gp/product/) on amazon.com and amazon.co.uk, the extension reads the ASIN, the price and the currency Amazon shows prices in, the package or product size and weight, and the category from the breadcrumb. That is all the page content it reads: it does not read your Amazon account, orders, cart, search history or delivery address. These details are used on your device to calculate fees and are never sent anywhere.

Network requests

Amazon's fees are built into the extension in US dollars and British pounds. When Amazon shows prices in another currency, for example in euros when you deliver to the Netherlands, the extension needs an exchange rate. It downloads the latest European Central Bank reference rates from Frankfurter (api.frankfurter.dev), a free exchange rate service.

• The request goes to api.frankfurter.dev and contains only a currency code: from=USD on amazon.com or from=GBP on amazon.co.uk. It is sent without cookies and does not include the address of the page you are on. Frankfurter receives your IP address, as any website does.
• Once the rates are downloaded, the extension does not request them again for a day, or for an hour if the currency you need was missing. If the download fails, it tries again later.
• Without a connection, the extension uses the last rates it saved, however old they are. The card and the popup show the rate and its date.
• If there is no rate at all, the extension asks you to enter the price in US dollars or British pounds.

When Amazon shows prices in US dollars on amazon.com or in British pounds on amazon.co.uk, no request is made. The extension makes no other network requests and sends nothing to the developer.

What stays in your browser

The extension saves the following in chrome.storage.local, on this device only:

• Your settings: whether the card is shown on product pages, whether it is collapsed, and whether you are VAT registered.
• For each product you work with: the costs you enter (product cost, inbound shipping, months in storage), the currency of those costs, a sale price you type when the card has no price it can use from the page, with its currency (clearing the field deletes it), and any category, size or weight you correct by hand. Up to 500 products are kept; the oldest are removed first.
• The last exchange rates downloaded for US dollars and for British pounds, with the date of the rates and the time they were downloaded.
• The last values you used in manual mode.
• The state of the rating prompt: the number of days you saw a calculation, the last such day, whether you answered, how many times you chose “Not now”, and the date until which the prompt is hidden.

A sale price you change while the card uses the price from the page is not saved. Nothing is synced to your Google account. Everything is deleted when you remove the extension.

Permissions, explained

• storage — to keep the settings, costs, typed prices and exchange rates listed above on your device.
• scripting — to inject the card into Amazon product tabs that were already open when you installed or updated the extension, and again when you open the popup or use the right-click menu on a page where the card has not loaded, so you do not have to reload the page.
• contextMenus — to add “Show FBA Revenue Calculator” to the right-click menu on Amazon product pages.
• activeTab — when you click the extension icon, to read the address of the current tab, so the popup shows the numbers for the product you are viewing or tells you the site is not supported.
• Access to https://www.amazon.com/* and https://www.amazon.co.uk/* (Chrome shows this as “Read and change your data on www.amazon.com and www.amazon.co.uk”) — to read the product details above and show the card under the price on product pages. The extension adds nothing to other pages of these sites.

Pages the extension opens

• A welcome page, once, after you install the extension, and a short survey page after you remove it.
• After you have seen a calculation on 5 different days, the card on the product page and the popup ask “Is FBA Revenue Calculator useful?”. Choosing 4 or 5 stars opens the Chrome Web Store reviews page; choosing 1 to 3 stars opens a feedback page. “Not now” hides the question for 30 days; the second time, for good. Nothing is sent when you click.
• The welcome, survey and feedback pages are hosted on GitHub Pages and count visits with anonymous analytics. GitHub Pages and Google Fonts receive your IP address, as any website does. The survey and feedback forms send your answer to Google Forms only when you click “Send feedback”.
• “Compare with Amazon's official calculator” opens Amazon's Revenue Calculator on sellercentral.amazon.com or sellercentral.amazon.co.uk.

Changes

If this policy changes, the new version will appear on this page with a new date.

Contact

Questions about privacy? Open an issue on GitHub.

Amazon is a trademark of Amazon.com, Inc. or its affiliates. Chrome is a trademark of Google LLC. FBA Revenue Calculator is an independent project and is not affiliated with, endorsed by or sponsored by Amazon or Google.