Updated: Dec 7, 2021
I put together some resistor lookup tables for different combinations of LEDs and power supplies that I use myself when wiring up some lights. These can help you pick the right resistor to use in your wiring circuit and also calculate what size power supply you will need to power all of your LEDs. Since LEDs don't draw much power, you can usually ignore the size of the power supply unless you have a lot of lights. Even a couple of dozen LEDs can be powered for a long time with a pair of AA-size batteries.
Here is a PDF version of the worksheet you can download. The individual tables in the document are also in this post farther down.
Here is a video showing how to use the resistor lookup tables.
Here are the individual tables from the PDF document for quick reference.
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