What this is actually doing.
This is the focused version of “Line height visualiser”: do the one job, inspect the result, and move on without opening a full editor.
Type, Layout & Effects
Line Height Visualiser.
Preview body copy at a chosen line height.
1 Enter2 Adjust3 Use result
Input
Answer
One annoying job. No software. No account. Done in the browser.
1.5 line height
One annoying job. No software. No account. Done in the browser.
Body copy often lands comfortably around 1.4–1.7, depending on the typeface and measure.
Useful to know
Four things worth knowing.
Where it stops.
It solves the named job, not every problem around it.
What to inspect.
Judge it at the size it will actually be used. Typography and spacing are partly optical.
Worth knowing.
Keep the original until the finished result has worked in the place you made it for.