css 9pt is equal to how many px

CSS 9pt equals 12px. The calculation formula of pt and px is "pt=px*dpi/72", and based on 96dpi (default) under Windows, "9pt = 9 * 1/72 * 96 = 12px".

The operating environment of this tutorial: windows7 system, css3 version, Dell G3 computer.

css pt and px units

pt (point, pound): is a physical unit of length, referring to 1/72 of an inch.

px (pixel, pixel): It is a virtual length unit, which is the digital image length unit of the computer system. If px is to be converted into physical length, the precision DPI (Dots Per Inch, pixels per inch) needs to be specified. , generally there is a DPI option when scanning and printing. The default for Windows systems is 96dpi, and the default for Apple systems is 72dpi.

The conversion formula between pt and px can be obtained according to the definition of pt:

pt = 1/72 (inch), px = 1/dpi (inch)

So

pt = px * dpi / 72

Calculated based on 96dpi under Windows:

1 pt = px * 96/72 = px * 4/3

For example, no matter which operating system the Firefox browser defaults to, the DPI is 96, so in fact 9pt = 9 * 1/72 * 96 = 12px.

So, although the "I" in "DPI" and the "inch" in "1pt is equal to 1/72 inch" do not represent physical inches, the two units are equal to each other. , it is eliminated in the multiplication.

So, how to calculate the real physical length? Please take out a ruler, measure the visible width of your monitor (in my case, it's 11.2992 inches), and divide it by the horizontal resolution (in my case, it's 1024 pixels). The result is the physical length of each pixel.

Now we can answer the question, how much space does the 9pt font on the web page take up? The answer is:

9 * 1/72 * 96 * 11.2992 / 1024 = 0.1324 inches = 0.3363 cm

Although pt is an absolute unit, it is only for output devices. It is a very useful font unit in text typesetting tools (word, abobe). No matter what the resolution of the monitor is, the result printed on paper is the same.

But the web page is mainly for screen display, not for printing and other needs. And px can accurately represent the position and size of elements on the screen.

certainly. When dpi is 96, 9pt=12px.

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