Here are a number of online calculators that have been identified by other engineers as being helpful. Add them to your toolbox as another resource for getting the job done.
Resistor Calculator Allows you to calculate resistor values from color codes.
Wire Converter will calculate the resistance and amperage for copper wire based on gauge.
Megaconverter 2 world’s favorite research site, with easy interface and more converters.
Scientific Calculator online interactive math and scientific calculator that is easy to use