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I am new to Latex and from what I know I can determine the font size by using: \large,\Huge, etc. However, I want to know how to accurately determine the font size with absolute numeric accuracy. Is there any such way? Any help is appreciated.

Kani Pen
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  • I'm sure that there is but someone else will have to help you. All that \large etc do is change the current font size. The basic font size is set by the class option. Particular font sizes depend on the particular font being used. You have to specify the font and size to get the details (such as the height, depth, width of the characters). – Peter Wilson Jul 31 '22 at 18:18
  • @PeterWilson I am using the default latex font. – Kani Pen Jul 31 '22 at 18:43
  • Which document class you employ? Do you specify an option such as 10pt, 11pt, or 12pt at the document class stage? – Mico Jul 31 '22 at 18:45
  • @Mico I am using article document class and I do not specify the text size in the document class stage – Kani Pen Jul 31 '22 at 18:47
  • \fontsize{size}{baselineskip}\selectfont Foo. – tush Jul 31 '22 at 19:01

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Since you employ the article document class and don't specify an explicit font size option, the default font size is employed, which is 10pt. In TeX and LaTeX parlance, 1pt=1/72.27in. Be careful: Adobe and many other software companies set 1pt=1/72in.

Furthermore, \subsection and \section text employs \large and \Large, respectively, for font sizes of 12pt and 14.4pt, respectively. Footnotes are typeset at, you guessed it, \footnotesize, or 8pt. In math mode, first-level and second-level subscript and superscript material is typeset at 7pt and 5pt, respectively.

Mico
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  • I am curious to know why TeX or LaTeX would use 1pt = 1/72.27 inches, when 1 point is and always has been 1/72 inch in printing and all other contexts as far as all sources I am aware of. You mention that "Adobe and other software companies set 1pt =1/72 in" when it would seem to be the case that they simply follow the completely normal standard, not something they have arbitrarily chosen themselves. Likewise, Adobe use the special convention that 1cm = 1/100 metre, and 1 ft = 1/3 yard. Genuinely seems odd for any software to "define" a unit differently from everyone else. Anyone know why? – AdamV Aug 01 '22 at 06:25
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    @AdamV - What's the basis for your claim that "1 point is and always has been 1/72 inch in printing"? To the best of my knowledge, Adobe was the first organization to adopt the "72pt=1in" convention. According to the https://en.wikipedia.org/wiki/Point_(typography) Wikipedia page, TeX's "72.27pt=1in" convention is based on the "American point system", which has been around since at least the 1890s. As a general matter, the exact size of "printer's points" has been quite variable ever since movable print was invented. – Mico Aug 01 '22 at 07:57
  • I do not believe that printers in the days of movable type would have been doing the maths to divide by 72.27. But dividing by 12 and by 6 would make sense. As things moved into a digital world, we inherited that measurement. The only thing that seems to have changed back in the history of this is which definition of an inch was being used, ie variations in imperial measurements. This led to different "translations" into metric, which are now being used to back-translate into imperial. If you convert US fl oz into ml, then into UK fl oz you get a different number than you started with. – AdamV Aug 02 '22 at 11:17
  • @AdamV - In the Wikipedia page I mention in my earlier comment, there's a table labelled "Various point definitions". It states that the "American point" definition of 1886 is 1pt=0.013837in; this is an exact value, not an approximation. Knuth's definition, viz.,1pt=1/72.27in, differs from the exact value by merely 1 part in 100 million. Knuth was rather clever in coming up with this easy to remember definition, no? IMNSHO, you really ought to be asking why Adobe chose the definition 1pt=1/72in in 1984, and not why Knuth chose to work with the existing "American" point definition. – Mico Aug 02 '22 at 12:50
  • @AdamV - How does the fact that the British and US definitions of gallons, quarts, fluid ounces, etc differ substantially have any bearing on the subject you've chosen to raise? AFAICT, your claim that "1 point is and always has been 1/72 inch in printing" remains wholly unsubstantiated. – Mico Aug 02 '22 at 12:55
  • I was curious why TeX chose a non-integer denominator for the fraction. I don't actually care all that much, it just seemed curious. Nothing you have presented convinces me that any printer in history used this measurement, it is only the conversion into metric of different versions of an inch, then back again to modern imperial inch that means we end up at this weird number. In other words, it is not "defined as" 1/72.27 of an inch, but as 0.3515 mm, which now translates to that number based on current inches. Like I say, I don't care, I just wondered if anyone knew why that choice was made. – AdamV Aug 10 '22 at 07:36
  • @AdamV - What's the basis for your apparent claim that an "American point" was ever meaningfully defined in millimeters? 1/72 and 1/72.27 differ from each other by almost 4 parts in 1000. The 1959 redefinition of inches (to 1in=2.54cm) adjusted the length of an inch (expressed in metric terms) by merely 2 parts in 10000. Hence, the 1959 redefinition cannot possibly be a valid basis for your claim. Knuth did not invent the measure of length called the "American point". All he did was to come up with a simple mnemonic, which differs from the exact defintion by about 1 part in 100 million. – Mico Aug 10 '22 at 08:23
  • @AdamV - A slight correction to what I wrote a short while ago: The 1959 international redefinition of the absulute length, in SI units, of a US "statute yard" (aka "survey yard"), led to a decrease from 0.9144083 cm to 0.9144 cm, i.e., a change of almost 1 part per 100000, not 2 parts per 10000 as I wrote earlier. The length of a US statute yard, in terms of SI units, did not change between 1869 and 1959. Hence, any redefinitions of the absolute length of an inch over the past 150 years simply cannot possibly explain the discrepancy between 1/72 and 1/72.27. – Mico Aug 10 '22 at 09:32
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    One reason that Knuth chose the size of a point that he did was to match the appearance of his existing books, which were composed on Monotype typesetting machines. That was the measure used by Monotype. – barbara beeton Nov 26 '22 at 14:14