Why there is no number here
Keyword difficulty is not something a search engine publishes. Every tool that shows one has built its own estimate, and every one of those estimates is derived from the same raw ingredient: the pages currently ranking on the first page, and how many other sites link to them. Strip that away and there is nothing left to calculate from.
Getting it requires two paid feeds — a search-results provider that reports the live first page for a keyword in a specific country, and a link-metrics provider that reports how many referring domains each of those pages has. Neither is connected to this tool. Rather than estimate around the gap, the tool reports the gap.
This is a deliberate trade. A fabricated 63 looks more useful than "no score", right up until somebody picks a keyword because of it. A number derived from nothing is not a cautious number — it is a wrong one, and it carries the authority of the interface it is printed in.
How the score is built when data is available
The model uses six signals, each weighted, all of them derived from the current results for the keyword. Domain strength of the ranking sites carries 25%, the strength of the specific ranking pages 20%, the backlinks those pages hold 20%, the number of distinct referring domains 15%, how uniform the first page is 10%, and how much room search features leave for organic results 10%.
Signals with no data are not counted as zero. They are named, excluded, and the remaining weights are rescaled — so a missing backlink feed lowers confidence rather than dragging the score toward easy. A score is only produced when at least five results are available and the signals with data cover at least 60% of the total weight; below that, the answer is again no score.
The result is labelled AllSolutions4You Difficulty, not Google Keyword Difficulty. It is our estimate on our scale, it is not a Google metric, and it cannot tell you whether you will rank.
What to do without a difficulty score
Open the search results for the keyword yourself and read the first page. If the results are large publishers, established retailers and comparison sites, the keyword is competitive regardless of what any tool would have scored it. If several results are forum threads, thin blog posts or pages that do not really answer the query, there is room.
Length is a rough proxy worth using. A three- or four-word phrase usually faces fewer strong pages than a single word, because the intent is narrower and fewer sites have written for it specifically. It is a weaker signal than the real thing, which is why it is presented here as a description of the keyword rather than as a difficulty rating.
For a portfolio of keywords rather than one, Google Search Console is the honest source. It reports the impressions and positions you already have, which is data about your own site, not an estimate about somebody else's.