LED Array Calculator

Design a series-parallel LED array — get resistor value per branch, total current and power.

Resistor per branch

300 Ω

E12: 270 Ω

Total current

44.4 mA

Total power

533 mW

Frequently Asked Questions

How many LEDs can I put in series?+
As many as the supply voltage allows: LEDs in series × forward voltage must be less than the supply voltage (leaving ~1–2 V for the resistor).
Why use parallel branches?+
Parallel branches increase total brightness (more LEDs, more current) without requiring a higher supply voltage. Each branch gets its own current-limiting resistor.