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About this tool
Compare title variants side by side for length, mobile truncation, keyword position and shouting, with a transparent score out of 100.
This tester compares video title variants on the mechanical properties that decide whether a title is readable where it appears: total length against YouTube's 100-character limit, the point at which it clips in the sidebar, mobile feed and desktop search, whether the focus keyword survives inside the first 40 characters, and whether the title shouts. Each variant is scored out of 100 against a published five-part rubric, with every point traceable to a criterion. It measures structure, not click-through rate — that only a real test can tell you.
Open YouTube Title A B Tester on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
See each title clipped at four different surface widths, not just one generic count.
Thirty points for fitting the feed, twenty-five for keyword position, and so on — no hidden model.
Up to twelve variants ranked with the spread between best and worst shown.
One hundred characters, including spaces. Anything longer is rejected when you publish. The practical limit is much lower, because most surfaces clip the title well before that point.
It depends on the surface and device, but roughly 40 characters in the suggested sidebar, 55 in the mobile home feed and 70 in desktop search results. Treat those as working approximations — font, language and screen width all shift the real cut-off, which is why the important words belong first.
There is no reliable evidence that full capitals help, and they cost readability and accessibility — screen readers may spell out capitalised words letter by letter. One capitalised word for emphasis is common; a title in all caps mostly signals low quality.
No. It measures length, truncation, keyword position and tone, which are the things you can check before publishing. Actual performance depends on thumbnail, topic and audience, so run a genuine test in YouTube Studio to compare variants on real traffic.