LED Resistor Calculator
Calculate the correct resistor for your LED circuit. Works for single LEDs, series strings, parallel arrays, and mixed configurations. Beginner-friendly — hover any ? icon for explanations.
⚠ Calculator in Development — Results should be independently verified before use. Calculated values are theoretical; real-world component tolerances, temperature, and manufacturing variations may produce different results. Always double-check with a multimeter when possible.
Found an issue or error? Contact us — please include your share link and a description of the problem so we can reproduce and fix it.
Found an issue or error? Contact us — please include your share link and a description of the problem so we can reproduce and fix it.
1
Supply Voltage
?
V
2
Circuit Configuration
Single LED
One LED, one resistor. The simplest and most common setup.
Series String
Multiple LEDs chained end-to-end. Same current through all. One resistor total.
Parallel Array
Multiple identical LEDs side-by-side. Each branch shares equal voltage.
Mixed (Series+Parallel)
Multiple series strings running in parallel. Each string gets its own resistor.
Single LED: Connect one LED and one resistor in series between your power supply and ground. This is the standard beginner setup.
3
LED Specifications