Calculator KB-22
LED Strip Power Supply Calculator
Choose a power supply and find out where and how many times to connect power.
Result
In brief: Choose a power supply for 5, 12, and 24 V LED strips: power with headroom, current, the nearest standard power supply, number of connection points, and wire gauge. Example: Standard power supply: 100 W.
Calculation example
| Strip length | 5 м |
|---|---|
| Power per meter | 14.4 W/m |
| Voltage | 12 V |
| Power headroom | 20 % |
| Standard power supply | 100 W |
|---|---|
| Strip power | 72 W |
| Current | 6 A |
| Including headroom | 86.4 W |
| Connection points | 1 pcs |
| Wire gauge to connection point | 1.5 mm² |
How it is calculated
I = P / U
PPSU = P · (1 + headroom)
Power is calculated by simply multiplying the strip length by its power per meter, while 20% headroom keeps the power supply from running at its limit. At low voltages, current matters more: the strip’s copper traces are thin, so long sections need power fed in at several points.
What to look for
- A 24 V strip draws half the current at the same power and provides more even lighting over longer runs.
- Enclosed power supplies overheat inside profiles: leave room for airflow or choose a larger power reserve.
Frequently asked questions
What power supply do I need for 5 m of 14.4 W/m LED strip?
The strip draws 72 W, or 6 A at 12 V. With a 20% margin, you need 86.4 W, so a standard 100 W power supply will do.
Can I power a strip longer than 5 meters from one end?
It’s best not to: voltage drops along the strip’s copper traces, so the far end shines dimmer. Feed power from both ends or every 5 m. 24 V strips are less affected by this.
What wire do I need to connect the strip?
For 6 A and a short run, 1.5 mm² will do. For a longer run, use a larger cross-section to keep the voltage drop at 12 V below 3–5%.
