LED Power Calculator
Calculate power supply requirements for LED strip lighting. Enter strip length and wattage to size your power supply with proper safety margin.
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How to Use This Calculator
Size your power supply correctly for LED strip lighting projects:
- Enter the total length of LED strip you'll be using in feet or meters.
- Input the power consumption per unit length (typically listed as watts per foot or meter on the strip specs).
- Add a safety margin (20% is recommended for reliability and heat management).
- Click 'Calculate' to see the total wattage and recommended power supply size.
Why This Matters
LED strips are popular for under-cabinet lighting, accent lighting, and decorative installations, but they require properly sized power supplies. An undersized power supply will run hot, dim the LEDs, shorten lifespan, and potentially fail dangerously. An oversized supply wastes money and space. The key is matching the power supply to actual needs with appropriate headroom for reliability and future expansion.
- Prevent power supply overheating and premature failure
- Ensure LEDs operate at full brightness
- Extend lifespan of both LEDs and power supplies
- Calculate correct wire gauge for LED runs
- Plan multi-zone installations with proper power distribution
Worked Examples
Under Cabinet Lighting
Installing 12 feet of LED strip rated at 4.4W per foot for kitchen cabinets.
Accent Lighting
Running 5 meters of RGB LED strip (14.4W/m) around a room perimeter.
Long Run Consideration
20 feet of high-density strip at 7W/ft. Single run or split feeds?
Common Mistakes to Avoid
- Sizing power supply exactly to load with no margin - always add 20% for reliability.
- Ignoring voltage drop on long runs - LED strips dim noticeably over long distances, especially 12V.
- Using watts per meter specs with foot measurements (or vice versa) - double-check units.
- Forgetting that RGB and RGBW strips draw more power at full white than single colors.
- Not accounting for multiple zones when planning power supply capacity.