Any way to change default font size for symbols?

I’d like to have all my symbols default for a .40" font for everything to make my schematic more readable on an A4 print out.
At .40" resistor values fit inside the large resistor symbol more comfortably etc…etc…
Is there any way to make this the default?

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There is no such thing as a default size for text.
The size for each text is defined in the library for each text separately.

The reason for the uniformity of 50mil for all text sizes is because of the KLC (KiCad Library Convention) which states:

S3.2 Text fields should use a common text size of 50mils

  1. All text fields (pin name, pin number, value, reference, footprint, datasheet) should use a text size of 50mil ( 1.27mm ).
  2. Pin names and pin numbers can use a text size as small as 20mil if the symbol is small or has special geometry.

Here I’ve used both sizes for a comparison.
The rightmost two resistors are rotated 180 degrees:

For me the size of 50mil (for R50 and R51) fit just fine. There only is a slight annoyance that the text is not centered for symbols that are rotated 180 degrees.

I do agree that the somewhat smaller text of R40 and R41 do look slightly better on the monitor (where you can zoom in a lot) but if printed on paper the 50mil text is already quite small, and I would not want smaller texts on paper.

In KiCad V5.1.x the only way I know of to do this is to search through the KiCad files with a text editor or write a script to change it either in all the libraries or in the schematic itself.

In KiCad-nightly V5.99 there is: Eeschema / Edit / Edit Text & Graphics Properties … with extensive search and replace (inclusive orientation, text size, bold, italic, etc). It looks like:

Another subject:
The SI prefix for “Kilo” is the lower letter k.

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In, you can change some sizes - the menus shown below…
One changes the default size of the Text Tool, the other the default size(s) of Symbol’s Text and Pin size text…

The first is the default for adding text strings, and the second is for defaults in the Symbol Editor, and thus for creating new symbols or changing symbols.

None of those two influence the text size of existing library symbols.


I think that’s the problem.
Many many other items can be configured, some in great detail, but this seems overlooked.
Not everyone is going to have access to an A5 or similar size printer, so whilst making it a little harder to read i try to make my schematics as dense as possible.
I use many tricks to maximize usable space like putting resistor values inside the resistors, moving cap values closer to the caps, etc…etc…

I stumbled across the 50mils default in the guidelines when looking to edit a symbol that needed attention and became aware of that. Being able to override that globally would be great, looks like KiCad 6 might have some utils in it for that.

All replies much appreciated, i think I’ll just forge on manually for now.

I’m working on learning Python, so might be able to use that in future to build my own default lib modified from the official ones.

That’s probably the way to go. Standard (ISO, IEC, etc.) size would be 2.50 mm (≈ 2.54 mm = 0.1″ = 100 mil) anyway (i. e. grid size, which would be 1.8 mm or 2.0 mm minimum). Smaller would require to scale down everything (fonts and symbols). Example here. (Before computers, a common schematic paper size was ISO A3 landscape, which was then scaled by √½ ≈ 70.7% to ISO A4 if required.)

No. I do not agree with that.
This is the problem:

Making schematics “dense” makes them much harder to read.
Such “dense” schematics can still generate a valid netlist, but generating a netlist is not the main reason for a schematic. The main reason for a schematic is to give a human readable (and check-able) representation of an electronic circuit. Readability is therefore a very important part of a schematic.

Some people draw rectangular (dotted) boxes around schematic blocks, which I also consider a bad habit, because those boxes do not add any meaning but consume time for maintaining.

I also used to try to cram a whole schematic on a single A4 sheet and eventually realized that it takes a lot of time to make any changes or add small things, and makes the schematic harder to read.
I think this habit grew from reading too many magazines, where schematics get redrawn just to fit in the smallest rectangle possible for printing purposes (Printing 50.000 copies is expensive).

You write that the way you draw the schematic makes it harder to read. And that is probably while you’re working on a schematic. Now think about sharing that schematic with someone else who has not seen it, or finishing the project, and then re-opening it years later for modifications. The problem of (un-) readability becomes much larger then.
Making schematics “more dense” makes them harder to read, and also costs extra time. And later you spend more time to refresh your memory on how the schematic works. So you loose time twice, while making schematics “more dense” gains you nothing.

Overall I find it best practice (both for readability, and for maintaining & modifications) to leave a bit of room around schematic blocks, so they can be easily selected by drawing a rectangular box around them (KiCad has no “lasso” tool for selections) and to add text in a big and possibly Bold font to give an explanation of what different sections do.
The empty space helps in separating the logical blocks from each other, in much the same way as strategically placed empty lines makes source code more readable.

I would agree with @paulvdh here. You need space to make a schematic more readable. If the need for printed A4 sided output is a hard requirement, you can spread your design over multiple pages. Just add another page to the design. i find this often helps you look at the overall design more critically. KiCad supports either multipage or hierarchical schematics.

As of now, it is just speculation of how “dense” and readable (and maintainable) your schematics are.
If you’re interested in what we think of your style of drawing schematics, then post an example project to give us a better idea of what it actually is all about.

You of course decide what’s best for you, but I have still a couple of points why I wouldn’t put values inside symbol graphics.

First, if you want to keep all texts horizontal it’s not possible if you rotate resistors 90 degrees.

Second, you can’t put text inside some other components anyway, so you loose consistency and ease of reading which comes from that. If putting text inside some symbols is your way to fit all the design in the same page it’s not the best way.

If you don’t need to print the schematic physically (in a paperless office) you can also make the page bigger. Using A3 instead of A4 gives you twice the space in one page. Then you don’t need to navigate between hierarchical sheets so much.

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