Resistor Toolkit (抵抗計算ツールキット)

This is a browser tool that handles the troublesome calculations involved in resistor calculations.
It has the following features:

1 Color Code
Simply select colors and the resistance value is displayed instantly. Since I can never remember color codes, I really wish they would just write them in numbers already.

2 Spreadsheet
Just input values into a table and it calculates the combined resistance. You can easily perform the tedious calculations for parallel connections.

3 Formula Calculation
From formulas with mixed series and parallel connections like 1Ω + (2Ω ‖ 3Ω), it calculates the combined resistance.

4 Optimal Resistance
Input the "desired resistance value" and "resistors on hand," and it automatically calculates the optimal connection pattern. No more need to trial-and-error multiple patterns in your head.

Please feel free to use it.