A walkthrough of every input on the Power Calculator, and how to read the results it gives you.
Select your strip from the dropdown (WS2812B, SK6812, APA102, and others), or choose "Generic" if your strip isn’t listed. Each preset carries the correct per-LED current draw so the calculator can estimate power accurately.
Enter how many LEDs per metre your strip has (commonly 30, 60, or 144) and the total strip length in metres. These two numbers determine the total LED count, which drives every downstream calculation.
Choose 5V, 12V, or 24V to match your strip. This affects current draw: a 5V strip draws roughly 2.4× the current of an equivalent 24V strip for the same total wattage.
If you cap brightness in WLED’s LED settings (Max Current Limit), toggle "Custom current limit enabled" and enter that value in mA. This lets the calculator reflect your actual real-world draw rather than the theoretical maximum.
This percentage represents the realistic average brightness/colour mix you’ll run day to day, not full white at 100%. It’s used to give you a "real-world amps" figure alongside the theoretical worst case.
Select your controller (ESP32, ESP8266, or a specific board) and enter the length of the data wire between the controller and the first LED. Long data leads may need a resistor or level shifter — the calculator will tell you if one is required.
The results panel gives you the recommended power supply rating, fuse size, minimum wire gauge, data resistor value, and whether a level shifter is needed. The Power Injection Map below it tells you exactly where to inject extra power on longer runs.
Always size your power supply and fuse using the calculator’s recommended values, not the bare minimum. A 20–30% safety margin protects against voltage sag and component ageing.
The Power Calculator is designed to be used at the planning stage of a WLED build, before you purchase components. Working through the fields in order takes about two minutes and gives you a complete set of electrical specifications for your installation.
Choose the chipset and density that matches the strip you are planning to use (or already have). If you are not sure which strip to choose, the LED Strip Comparison page explains the key differences. For most beginner builds, WS2812B 60 LED/m on 5V is the right starting point.
Enter the total length of LED strip in metres. If you have multiple separate strips that will all be powered from the same power supply, enter the combined total length.
This is determined by your strip type — 5V strips (WS2812B, SK6812) require a 5V supply; 12V strips (WS2815, WS2811 12V) require 12V. Do not mix voltages between a supply and strip that do not match.
The default 70% represents typical ambient lighting use with mixed WLED effects. If you plan to run solid white at full brightness most of the time, increase to 90-100%. For sparse fire or sparkle effects at low brightness, reduce to 30-40%. This setting affects the real-world current estimate and the recommended PSU rating.
The output panel shows: recommended PSU rating (current in amps at your voltage), fuse rating, minimum wire gauge, whether a level shifter is needed, the data resistor value, and the maximum strip length per power injection segment. Use each of these values when sourcing and installing your components.