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Calculating Voltage, Current & Wattage
How Do I Calculate Voltage, Current, And Wattage For My LED Setup?
When planning your LED lighting installation, it’s important to understand the basic electrical values involved: voltage (V), current (A), and wattage (W).
These values help ensure that you choose the correct power supply and components to operate your system safely and efficiently.
Voltage (V)
What it is: Voltage is the electrical pressure that pushes current through the circuit.
What to know: All Ultra LEDs products specify the required input voltage — usually 12V or 24V DC. Always match the power supply voltage to the LED product’s rated voltage.
Current (A)
What it is: Current is the flow of electricity, measured in amperes (A).
How to calculate:
Use this formula if you know the wattage and voltage:
Current (A) = Wattage (W) ÷ Voltage (V)
Example:
- A 24V LED strip that consumes 48 watts:
- 48W ÷ 24V = 2A
This means your power supply needs to deliver at least 2 amps to run the LED strip safely.
If you want to learn how constant voltage and constant works, read our other article here.
Wattage (W)
What it is: Wattage is the total amount of electrical power consumed.
How to calculate:
If you know the voltage and current:
Wattage (W) = Voltage (V) × Current (A)
Example:
A 12V LED drawing 1.5 amps:
12V × 1.5A = 18W
This helps you determine how many LEDs your power supply can handle.
Why These Calculations Matter
- Ensures you select the right power supply size and avoid overloading.
- Helps determine how many LED strips or fixtures can be run together.
- Prevents common issues like flickering, overheating, or early failure.
Need help working out the details? Our technical support team is always here to assist.
Just let us know your setup, and we’ll help you calculate everything you need for a smooth, safe installation.
Author: Tom Cain, Technical Manager @ Ultra LEDs
Tom brings years of hands-on experience in professional LED lighting solutions, specialising in product development, system integration, and lighting control technologies. As Technical Manager at Ultra LEDs, he supports the team with in-depth knowledge across LED drivers, dimming protocols, and complex installations. His expert insights help ensure our content is accurate, relevant, and grounded in real-world applications.
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