Data methodology

1. Marketplace facts

Fees, fee formulas, listing limits, protection windows and payout rules come from each marketplace's official pages, read on the date shown in the article's sources list. We keep:

Where official pages disagree with each other, we quote the part that is unambiguous and point out the conflict. One example is a worked example that uses a different threshold from the text above it.

2. Worked examples

Examples use round, plausible numbers so that the method is easy to follow. They describe how to calculate, not what the market is. Every chart built on them is labelled "Illustrative example, not market data".

We do not publish figures like "average sell-through rate on Vinted" or "typical margin on sneakers". We have not measured them in a way we could defend, and we have not found public sources that measure them reliably. Articles show you how to measure these numbers for your own items instead.

3. Calculator formulas

The calculators run in your browser, and nothing you type is sent to us. Each tool page explains its formula. The core ones are:

Marketplace presets in the fee calculator only cover fees that work as "a percentage plus a fixed amount per sale", and only where we confirmed the numbers on the marketplace's own page. Each preset shows its source and date. Fees that depend on category, seller level or listing packages can't be captured in one preset; enter your own numbers for those.

4. reva price estimates

Some articles show what reva displays for a listing. reva reads public listings on Vinted, OLX and Allegro Lokalnie, groups comparable items, and builds a five-level price ladder:

Some limits to keep in mind:

• "Left the market" is not the same as "sold". A listing can disappear because it sold, because the seller removed it, or because it was reserved off-platform. reva cannot see which. The fair value is therefore an estimate of where items stop being available, not a record of sale prices.
• Estimates depend on comparables. A rare item, an unusual condition or a poorly described listing gives fewer and weaker comparables. reva shows a price confidence level for this reason. Treat a low-confidence estimate as a starting point for your own research.
• Nothing is guaranteed. Prices are estimates of the market at the time they were calculated. They are not promises of what you will sell for.

Screenshots and mock-ups of reva in articles use example values unless the caption says otherwise.

5. What we will not do

• Invent statistics, survey results or "studies".
• Present a competitor's missing public statement as a missing feature.
• Show an example number without marking it as one.
• Describe reva features that are still in build as available.

Read more in our editorial policy, or start with the resale pricing guide to see these methods in use.