Google snippet preview
Shows how your title and description look on Google, and whether they are too long.
Your browser does the calculations: what you type is never sent or stored.
Why the title is measured in pixels
Google doesn't count letters: it looks at how much space they take up. An "m" is wider than an "i", so two titles with the same number of characters can have different widths. Beyond about 580 pixels, the title gets cut off with "...".
What makes a good result
The title says straight away what the page is about, with the keyword at the start and the brand at the end. The description doesn't change your position on Google, but it convinces people to click: between 70 and 160 characters, concrete, with no promises you can't keep.
Mind the rules: for food, in the European Union health claims are only allowed if they are authorised (Regulation (EC) No 1924/2006). The tool warns you if it finds words like "detox" or "weight loss".