# What leading size should I set for 18pt font size?

I use `\fontsize{18pt}{20pt}\selectfont` comand because I want 18pt fontsize. Does rule fontsize+2 always apply? Say for 20pt font leading will be 22, 32 for 30 and so on.

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It's too tight. I wouldn't stay below 24pt for the baselineskip, but it depends also on the font you're using. –  egreg May 14 '12 at 21:27
Note that with `10pt` font, the baseline skip is `12pt`, that is, "font size + 20%", not "font size + 2pt". For `11pt`, baseline skip is `13.6pt` (font size + 13%). For `12pt`, its `14.5pt` (font size + 21%). –  Werner May 14 '12 at 21:32
Isn't this more of a design than a TeX question: borderline for on/off topic? –  Joseph Wright May 14 '12 at 21:47
@JosephWright For me it is not offtopic: I am required to use strict font sizes 14, 16 and 18, and they must look exactly like Microsoft Word's one (though now I understand that it is impossible due to other problems). I figured out how to set up fontsize, but I saw that there is second param which should be input by user. In the samples on the internet there is only basic case 10,12. So it wasn't obvious for me. –  dig May 14 '12 at 21:50
@dig Normally 18 x 1.2 they are multipliers = 21.6pt,however this might be too tight anything from 1.2-1.5 –  Yiannis Lazarides May 14 '12 at 21:53

The answer depends on the font: the size of ascenders and descenders. Fonts with larger ascenders/descenders require larger leading, fonts with smaller ones require smaller one.

For Computer Modern `size12.clo` recommends 22pt leading for 17pt font and 25pt leading for 20pt font, so for 18pt I'd take 23pt leading. These numbers would probably work for Times as well. For other fonts you need other adjustments.

However, a fine tuning of leading requires a real expertise in font and typography design, so if you have any specific recommendations for the font you use by the font author, you'd be better off following them.

Update: I was asked for other point sizes, so here I plotted the LaTeX values as defined in `classes.dtx`:

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I agree it depends on the font. But rather the other way. If a font has a small x-height, it will need less not more leading, because the ascenders and descenders appear to add white space. It also depends on line length. –  Paul Stanley May 15 '12 at 7:58
It depends a little bit on the language, too. German has a lot of capital letters and needs, therefore, a different approach than English. –  Andy May 15 '12 at 10:13
@Boris Can you give an advice on leading size for Computer Modern sizes 14 and 16 too? –  dig May 15 '12 at 17:17
@dig Please see update –  Boris May 15 '12 at 18:30