LED Strip Length Calculator

Calculate an LED strip total LED count, wattage, and the power supply size you need.

Power Supply
— watts min
Includes 20% headroom.

Usage Tip

Keep single runs under about 5 meters for 12V strips; longer runs need power injected at both ends to avoid dimming.

THE MATH
meters = length × 0.3048
total watts = meters × watts per meter
power supply ≥ total watts × 1.2
An LED strip draws a fixed wattage per meter, and the power supply must handle the total with headroom. LED count and wattage both scale with strip length and density.
Enter the strip length in feet, the LED density, and the watts per meter from the strip spec.
Size the power supply at the recommended minimum or the next size up.
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.