LED Array Calculator
Resistors for multi-LED series/parallel arrays.
Resistor per string
300 Ω
Nearest E12: 330 Ω · E24: 300 Ω
Resistor power
0.12 W
Use at least 2× this rating for headroom.
Voltage headroom
6.00 V
Total Vf = 6.00 V
Total array current
20.0 mA
Total array power
0.24 W
What is this tool?
Driving multiple LEDs needs attention to series voltage drop and parallel current. This calculator sizes resistors for series strings and parallel branches from supply voltage, LED forward voltage/current, and counts — and flags configs that exceed the supply.
How to use it
- Enter supply voltage, LED Vf and If, and series/parallel counts.
- Read suggested resistor value(s) and total current.
- Check feasibility notes before building.
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