The characteristic of LEDs can vary quite a bit. The voltage drop usually depends on the color, but your LED might be different. This is just a guide, check your datasheet or meassure it. Typically red, orange, yellow LEDs have a voltage drop of 1.8V-2.0V and green, blue, pink/purple, white of 3.2V-3.3V.


Direct

Charlieplexed

Direct

red orange yellow green blue pink/purple white
V/mA 5mA 10mA 15mA 20mA V/mA 5mA 10mA 15mA 20mA
3.0V 220Ω 100Ω 82Ω 68Ω 3.0V - - - -
3.3V 330Ω 150Ω 100Ω 68Ω 3.3V - - - -
3.7V 390Ω 180Ω 120Ω 100Ω 3.7V 100Ω 47Ω 33Ω 33Ω
5.0V 680Ω 330Ω 220Ω 150Ω 5.0V 390Ω 220Ω 120Ω 100Ω

Charlieplexed

red orange yellow green blue pink/purple white
V/mA 5mA 10mA 15mA 20mA V/mA 5mA 10mA 15mA 20mA
3.0V 100Ω 47Ω 39Ω 33Ω 3.0V - - - -
3.3V 150Ω 68Ω 47Ω 39Ω 3.3V - - - -
3.7V 180Ω 100Ω 68Ω 47Ω 3.7V 47Ω 33Ω 22Ω 15Ω
5.0V 330v 150Ω 100Ω 82Ω 5.0V 180Ω 100Ω 68Ω 47Ω