Reference manual

This document is Copyright © 2019 by it’s contributors as listed below. You may distribute it and/or modify it under the terms of either the GNU General Public License (, version 3 or later, or the Creative Commons Attribution License (, version 3.0 or later.


Heitor de Bittencourt. Mathias Neumann


Please direct any bug reports, suggestions or new versions to here:

Publication date and software version

march 04, 2019


The Kicad Calculator gives you the Chance to calculate the most important Things without leaving Kicad.

The Calculator consists the following Options:

  • Regulators

  • Track Width

  • Electrical Spacing

  • Trans Line

  • RF Attenuators

  • Color Code

  • Board Classes



This calculator helps with the task of finding the values of the resistors needed for linear and low-dropout voltage regulators.


For the Standard Type, the output voltage V_out as a function of the reference voltage V_ref and resistors R_1 and R_2 is given by:


For the 3 terminal type, there is a correction factor due to the quiescent current I_adj flowing from the adjust pin:


This current is typically below 100 uA and can be neglected with caution.

To use this calculator, enter the parameters of the regulator Type, V_ref and, if needed, I_adj, select the field you want to calculate (one of the resistors or the output voltage) and enter the other two values.


The Track Width calculator calculates the trace width for printed circuit board conductors for a given current. It uses formulas from IPC-2221 (formerly IPC-D-275).



In the Picture you can see that you can edit the Voltage and the Calculator gives you the correct Values.

The minimal Values which orientatd at the IPC-2221 too.



Transmission line theory is a cornerstone in the teaching of RF and microwave engineering.

In the Calculator you can choose different sorts of Line Types and their special Parameters.



With the RF Attenuator you can calculate different things by choosing:

  • PI

  • Tee

  • Bridged Tee

  • Resistive Splitter

and change all their Parameters.

RF Attenuators


This calculator helps translating the color bars from the resistor to its value. To use it, first select the tolerance of the resistor: 10%, 5% or equal or smaller than 2%. For example:

  • Yellow Violet Red Gold: 4 7 x100 ±5% = 4700 Ohm, 5% tolerance

  • 1kOhm, 1% tolerance: Brown Black Black Brown Brown