How to use the drop cap size calculator
A drop cap enlarges the first letter to anchor the top of a paragraph, and sizing it by eye leaves it off the baseline of the last line it covers, with a gap underneath or the letter poking out. This calculator takes the body size, line height, line count and the cap height ratio of both fonts, returns the drop cap font size and line-height, and writes the CSS to paste.
The height covered is (lines - 1) x body line height + body cap height, because that is the distance from the cap line of the first line to the baseline of the last. The drop cap font size is that height divided by the drop cap font's cap height ratio, and line-height cancels out to exactly that ratio. Written as of October 2026.
No recommended line count is offered. There is no authoritative figure and the answer depends on page size and copy length. Cap height ratios differ per font, so they are inputs too. Ascender and descender metrics and browser differences in first-line handling are not modeled, so expect to nudge the margin a pixel or two after pasting the CSS. The initial-letter version does not work in Firefox.
Frequently Asked Questions
The tool does not decide for you. There is no authoritative figure, and the answer shifts with page size, copy length and typeface. Enter the line count you want and it returns the font size and line-height that match it.
The box height of a floated first letter is font size times line-height. Setting that box equal to the height being covered makes the algebra cancel, leaving line-height exactly equal to the drop cap font's cap height ratio.
Firefox does not support it. That is why the float version is the main code and the initial-letter version comes along as an alternative. Either way the real font metrics usually need a small visual adjustment.