LED Wattage Calculator
Calculate total power consumption for a group of LEDs or an LED strip, plus estimated running cost from hours used and electricity price.
W
hours
$
/ kWh
Total Wattage
10.0 W
Daily Energy Use
0.060 kWh
Daily Running Cost
$0.01
Monthly Running Cost
$0.27
How LED Total Wattage Is Calculated
This calculator finds the total power consumption of a group of LEDs or an LED strip — different from sizing a current-limiting series resistor for a single LED circuit. Enter either the number of individual LEDs and the wattage of each, or the length of an LED strip and its watts-per-meter rating (printed on most strip packaging), to get total wattage. From there, adding hours run per day and your electricity price estimates the running cost, the same way other appliance cost calculators on this site work.
Total Wattage (by strip) = Strip Length (m) × Watts per Meter
Daily Cost = (Total Wattage ÷ 1000) × Hours per Day × Price per kWh
Example
20 LEDs at 0.5W each draw 10W total. A 5-meter LED strip rated at 9.6W per meter draws 48W total. Run for 6 hours a day at $0.15 per kWh, that 48W strip costs about $0.043 a day, or roughly $1.30 a month.
Common Use Cases
- Sizing a power supply for a run of LED strip lighting or an array of individual LEDs.
- Estimating the electricity cost of decorative or accent LED lighting.
- Comparing total power draw between different LED strip densities or LED counts.
FAQs
How is this different from an LED resistor calculator?
An LED resistor calculator sizes the current-limiting resistor needed for a single LED circuit using Ohm's Law. This tool instead totals up power consumption across many LEDs or a whole strip, which is useful for power supply sizing and estimating running costs rather than circuit design.
Where do I find watts-per-meter for my LED strip?
It's usually printed on the strip's packaging or spec sheet — common values range from about 4.8W/m for basic strips to 14.4W/m or higher for dense, high-brightness strips. Check your specific product for an accurate figure.
Does this account for power supply efficiency losses?
No — this calculates the LEDs' own power draw. A power supply or driver isn't 100% efficient, so actual wall-outlet power consumption will be somewhat higher than the LED wattage alone, typically by 10-20% depending on the driver.