They are not answering the same question
Before comparing outputs it is worth noticing that these tools are not all estimating the same thing. One may be estimating the aftermarket resale value of a name — what another investor would pay. Another may be estimating end-user value, which is typically far higher and far less likely to be realised quickly. A third may be estimating what the name would fetch through its own marketplace. Three different questions produce three different numbers without any of them being wrong.
What each is built on
Broadly, appraisal engines draw on three kinds of input: recorded aftermarket sales, keyword and search data such as volume and advertising cost, and structural features of the name itself — length, extension, whether it is a dictionary word, whether it contains hyphens or numbers. Each tool weights these differently, and the ones operated by marketplaces have access to their own transaction history, which is data nobody else holds. Check each provider's own documentation for what it says it uses, because the weighting changes over time.
Registrar and marketplace tools
An appraisal offered by a registrar or marketplace sits inside a business that wants you to transact. That is not a reason to dismiss the number — access to proprietary sales data is a genuine advantage, and these are among the most data-rich tools available. It is a reason to read it in context: the estimate is a step in a funnel toward listing, buying or renewing, and the incentive does not point toward conservatism.
Keyword-driven tools
Tools built primarily on search and advertising data are strongest on descriptive, commercial names — the sort of phrase a business would target in paid search. Where a name maps cleanly to a keyword with real advertising spend behind it, this approach has something concrete to measure. It is weakest on invented brandables, which have no search volume by definition, and it can overvalue long descriptive phrases that read well as keywords but poorly as brands.
Where they agree, and what that means
Agreement between tools is the most useful signal any of them produce. If three engines built on different data land within a narrow band, the name has dense comparable sales and the range is real. That is worth more than any individual figure, and it is the case where you can price with reasonable confidence.
Where they disagree, and what that means
A wide spread — the kind where the low and high differ by a factor of ten — is not a sign that one tool is broken. It means the name sits in a category with sparse or highly variable comparable data, usually a short acronym, a coined brandable, or a name in a low-volume extension. The correct conclusion is that no automated estimate should drive your decision, and that you need either real comparable sales or a human view.
How to use all three properly
Run the name through each, record the low, high and spread, and ignore the average — averaging three estimates of different quantities produces a number that measures nothing. Use the spread to judge confidence, use the lowest figure as a floor for what a reseller might pay, and treat the highest as an end-user ceiling that requires the right buyer to materialise. Then verify against comparable sales, which is the only external evidence available.
The number none of them can give you
All three are estimating value in the abstract. None can tell you whether the name will sell, which is the question most owners actually have. That depends on discovery, pricing and buyer demand at a particular moment, and it is answered by listing the name where buyers look and seeing what happens — not by a fourth appraisal.
- The tools estimate different things — reseller value, end-user value, marketplace value.
- Agreement between them signals dense comparable data and a real range.
- A ten-fold spread means no automated estimate should drive the decision.
- Do not average them; read the low as a floor and the high as a conditional ceiling.