# How big is 4 cm

## The little font size multiplication table

General font size regulations are still circulating on the Internet, especially for students, but also for other target groups. Some universities still require a 12-point dissertation, possibly in the Times New Roman, and one wonders who actually wants to read it. The uncertainty is no coincidence, as there are hardly any compact and at the same time understandable guidelines with regard to font size. Time to shed light on the darkness.

### Typographic measurement system

When working with fonts, the typographic system of measurement is used instead of the metric system. So we do not measure and define in meters and millimeters, but based on history in the smallest, and therefore much more suitable, typographical unit, the point. Over the years and centuries there have been different sizes here too; For many years the Didot point, a further development of the Fournier point, was the standard in the world of typography. At 0.375 mm, it was slightly larger than today's PostScript or DTP point, the 0.353 mm amounts. So if you enter a font size of 10 points in Microsoft Word or Adobe InDesign, you specify that your font has a size of 3.53 mm. Actually.

### What is the font size?

Let us first define the term font size or font size. Strictly speaking, it is misleading, because neither in InDesign nor in Word or with other colleagues do we define the size of the font with the point input in the "Font size" input field - instead we specify the size of the cone. The font is a cuboid metal cone of a font from the lead type. On the upper part sits, mirror-inverted and raised, the printing symbol, the actual typeface; around it and next to it and there is more or less a lot of "air", i.e. a non-printing area, also referred to as meat or hallmark.

When Gutenberg set a 12-point font, the size of the cone and not the measurable printed letter was 12 points. Thus, the cone size is usually always larger than the actual typeface.

Now our name is neither Johannes Gutenberg nor do we fortunately have to carry type cases around. In the age of digital writing, there is no longer a physical cone. Nevertheless, the term and, above all, the meaning of the font cone are retained in the font design, because whoever defines a font size of 12 point in InDesign will determine precisely this cone size.

### Different measurement results

Now one could assume that for every font, let's say 15 percent flesh, i.e. non-printing material, would have to be thought away from the typeface. By entering 12 points, each font would then have an actually measurable size of 10.2 points at 15 percent. But this is not the case.

You probably know that: two fonts, placed next to each other in the same size, can either appear roughly the same, but they can also have significant differences in size. Apart from the size effect, which also plays an important role, the utilization of the cone has a considerable influence on the actual measurable final size.

This use of the cone, i.e. the design of the proportions of the printed characters and the air around them, is left to each type designer himself. Typographers who like it airier cut their font with a lot of flesh; other fonts have a large use of the cone and protrude - transferred to the lead cone, to the edge of the cone and even beyond it.

The lower the cone utilization, the smaller the font size that can actually be measured; the larger the cone utilization, the larger the font size.

### Different size effect

When deciding on a size and evaluating it, we must not forget the effect. There are fonts that not only have an identical cone size (we mark the fonts in 12 points), but also an identical measurable letter size (we measure an identical size of the capital letters with the typometer). And yet they look different in size and can be read differently, especially in small sizes - so they make different-sized impressions. Why is that?

A letter has many different characteristics; a "p", for example, protrudes down into the cellar, an "a" stays in the middle, a "b" goes up to the top, an "E" stays in the middle and at the top, an "O" sticks out A little further up, and capital letters with accents are the winners in the size competition. The following overview is intended to illustrate this.

In addition to the shapes, line widths and thicknesses of the letters, it is above all the Mid-lengthwhich influences the size effect. The middle length, also called x-height, is the height of the lower case letters such as the "m", "a" or "z". This size differs in relation to the capital height, ie to the "M", "A" or "Z". Often the letters have a size ratio according to the golden ratio - the factor is 1.6. The "M" is 1.6 times larger than the "m".

Fortunately, as always, these proportions are only a means; many fonts use different proportions, which also work. And even if you have to be careful with general statements when it comes to font size, it can be said that fonts with a large middle length in relation to the capital height appear larger than fonts in which the middle lengths are relatively small.

Remember: 12 points are not always 12 points - depending on the font, clear differences are possible; a 12-point font can appear as small as an 8-point font - or as large as a 16-point font.

### Measure font size

What to do if you have a template and need to determine the font sizes used there, for example because a flyer is to be laid out according to an old template?

There are different approaches here, but unfortunately no binding standards either. With the help of a typometer, i.e. a ruler for the typographical measurement system, printed fonts can be measured. But here, too, there are different measurement variants, different typometers and ultimately different point sizes.

### hp height

It is common to measure the hp height, i.e. the total height from the upper edge of an “h” or “b” or “d” or “l” to the lower edge of a “p” or “q”. Most typometers have printed rectangles ready for this; the motivated designer looks for the rectangle in which the characters “h” and “p” fit exactly and has thus read out the font size. If it weren't for the thing described above with the different cone utilization ...

### The capital height

Alternatively, some designers work by entering the capital height. Here, only the size of a capital letter without rounding is measured, for example that of an "H" or "M" - but they are also difficult to measure, especially for handwriting and handwriting. This size is of course not the font size that programs like InDesign expect under font size, because they want the cone size. So either empirical values ​​are necessary here or you know where to look to get from the capital height to the font or cone size.

### Which font size for what?

Due to the situation just explained, it is hardly possible to give serious font size recommendations. A good reading size for longer texts such as magazines and books is usually between 8 and 12 points; if you want to restrict further, you have to know the font used in order to be able to make a reliable statement. The same applies to business cards or letterheads, sizes between 8 and 12 points are also possible here. Captions, copyright information, footnotes and similar additional remarks can still be legible in 7 point, but this depends heavily on the font used and other details such as the line length, the amount of text or the background. Typefaces in 6 point usually require good glasses on the nose and are often used as a deterrent example of the "small print" in the contract.

### Conclusion: we know that we don't know anything

There is no general basis for the use of the cone or the font size that ultimately results from it. Font sizes are relative, and the trained eye and experience are the two helpers who, in addition to a few basic values, are most effective when choosing the right size.