Add up total watts (strip wattage/meter × length in meters), then add 20% headroom. A 5m strip of SMD 5050 at 14.4W/m needs 72W, so buy a 90W power supply.

Calculate total watts: W/m × total meters
Add 20% headroom: multiply by 1.2
Round up to next standard PSU size
Never run a power supply at 100% capacity

Strip Type	Watts/Meter	5m Total	PSU Size
SMD 2835	4.8W	24W	30W
SMD 5050	14.4W	72W	90W
SMD 5630	18W	90W	120W
COB	10W	50W	60W

Should I use 12V or 24V LED strips?

24V strips allow longer runs with less voltage drop. Use 12V for short runs under 5m and 24V for anything longer. Both produce the same light output.

12V: max 5m per run, cheaper controllers
24V: max 10m per run, less voltage drop
12V strips are more common and cheaper
24V preferred for professional installations

How much does it cost to run LED strips?

LED strips are very efficient. A 16-foot SMD 5050 strip draws about 70W and costs $0.50–$0.60/month running 6 hours/day at $0.12/kWh.

5m SMD 5050: 72W = $0.78/month at 6h/day
5m SMD 2835: 24W = $0.26/month at 6h/day
5m COB strip: 50W = $0.54/month at 6h/day
Much cheaper than traditional light fixtures

How do I avoid voltage drop in LED strips?

Never exceed 5m per run for 12V strips or 10m for 24V. For longer installations, inject power at both ends or use parallel runs from the power supply.

Voltage drop causes dimming at the far end
12V: inject power every 5m
24V: inject power every 10m
Use thicker wire (18 AWG+) for long cable runs

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Last Updated: Jun 17, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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