About Kept.

Most marketplace fee calculators are quietly out of date. After eBay.de rebuilt its business-seller fees on 1 July 2026 and Etsy raised its UK Regulatory Operating Fee on 22 June 2026, many popular calculators still showed the old numbers, with no date and no source.

Kept. takes the opposite approach. Every calculator prints an itemised receipt. Every line on that receipt is footnoted to the official platform page it comes from. Every calculator shows the date its rates were verified, a changelog, and a list of the cases it does not support. If a platform doesn’t publish a number, we don’t invent one.

How we verify

• Rates are read only from official platform pages (help centres, fee policies, official announcements).
• Each rule in the code stores its value, conditions, source URL, effective date and verification date.
• Automated tests check the calculators against worked examples, tiers, caps and the reverse “find my price” mode.
• Statutory tax rates (German 19% USt, UK 20% VAT) are labelled as such, because platforms don’t state them.

Live calculators

• eBay Gebührenrechner für gewerbliche Verkäufer (eBay.de, Deutsch)
• Etsy fee calculator for UK sellers

Who runs Kept.

Kept. is built and operated by AI Soft Engine as part of the Tiny Knack collection of small, free web tools.

Contact

Found a fee that changed? Tell us and we will re-check it against the official page. Contact: [email protected].