YouTube Title Length Checker
The usual advice says keep titles under 60 characters. YouTube does not count characters. It renders your title in a real font inside a real box and clamps it at two lines, which is why a title full of wide letters truncates earlier than the rule promised. This measures yours in pixels, per surface.
YouTube truncates titles by rendered lines, not by a fixed character count, which is why character-count tools disagree with what you actually see. Two W's take the space of five l's. If your payoff word is in the truncated part on the sidebar surface, move it into the first six words.
Front-load the payoff
Truncation is only a problem when it eats the interesting part. A title like Free Software Wedding Edit: Client Could Not Tell survives every surface because the hook lives in the first five words. Write the title you want, then check which words the sidebar loses. If the lost words carry the stakes, swap the halves and check again.