LED Power Consumption Calculator
Calculate power consumption, total current draw, and energy usage for single LEDs or LED arrays. Enter forward voltage, forward current, LED count, wiring configuration, and optional operating time to get instant results.
Each LED draws its own current — total current = If × N
For educational and reference use only. Always verify results before use in real-world designs or safety-critical applications. For more information, see Calculation Assumptions and Disclaimer.
How to Use This Calculator
Enter the forward voltage (Vf) from your LED's datasheet — this is the voltage drop across the LED when conducting. Enter the forward current (If) in milliamps, typically 20 mA for standard 5 mm LEDs.
Set the number of LEDs in your circuit and choose a configuration. Use Parallel when all LEDs share the same supply voltage with individual current paths. Use Series when LEDs are chained in a single loop. Use Individual to treat each LED as an independent unit (identical to parallel for power calculations).
Optionally enter an operating time in hours to calculate total energy consumption and a daily usage estimate.
Formula
Power consumed by a single LED:
Total power for an array of N LEDs:
Total circuit current — parallel or individual configuration:
Total circuit current — series configuration (same current through all LEDs):
Energy consumption over a given time:
Where Vf is forward voltage (V), If is forward current (A), N is number of LEDs, t is operating time (hours), and E is energy in watt-hours (Wh).
Example Calculation
Given: 10 red LEDs, Vf = 2.0 V, If = 20 mA, wired in parallel, operating for 8 hours.
Convert current: 20 mA = 0.020 A
Power per LED: 2.0 V × 0.020 A = 0.04 W
Total power: 0.04 W × 10 = 0.40 W
Total current (parallel): 0.020 A × 10 = 0.20 A = 200 mA
Energy consumed: 0.40 W × 8 h = 3.2 Wh
Power per LED: 40 mW | Total power: 0.40 W | Total current: 200 mA | Energy: 3.2 Wh
Frequently Asked Questions
How do I calculate the power consumed by an LED?
Multiply the LED's forward voltage (Vf) by its forward current (If) in amps. For example, a 2.0 V LED running at
20 mA (0.020 A) consumes 0.04 W per LED.
What is the difference between series and parallel LED configurations?
In a parallel configuration each LED draws its rated forward current, so total current multiplies with the
number of LEDs. In a series configuration all LEDs share the same current path, so total current equals the
forward current of a single LED while total voltage adds up across the string.
Why does total current matter for LED circuits?
The current source or driver must supply the total current for all LEDs. Exceeding 1 A is common in larger
arrays and may require a dedicated constant-current driver rather than a simple resistor.
How is energy consumption calculated for LEDs?
Energy (Wh) equals total power (W) multiplied by operating time (hours). For example, a 0.40 W LED array running
for 8 hours consumes 3.2 Wh.
What is a typical forward voltage for common LED colours?
Red and yellow LEDs typically have a forward voltage of 1.8–2.2 V. Green and blue LEDs are usually 2.8–3.5 V,
and white LEDs are commonly 3.0–3.5 V. Always check the datasheet for the exact value.