LED Strip Light Voltage Explained

Buyer guide

LED Strip Voltage Explained

Choosing the right voltage is one of the most important decisions in any LED strip project — and one of the most commonly misunderstood. This guide explains how it works, why Lumily specifies 24V as standard, and how to calculate exactly what power supply you need.

12V vs 24V LED Strips

LED strip lights run on low-voltage DC power — not the 230V AC from your mains supply. A driver converts the mains supply to the correct DC voltage for the strip. Most LED strips run at either 12V DC or 24V DC. Both deliver the same quality of light — the difference is in how they handle longer runs and power distribution.

12V

12V LED strips

  • More common in older product ranges and lower-cost strips
  • Maximum recommended single-feed run: 3–4 metres
  • More susceptible to voltage drop on longer runs
  • Require higher current — thicker cable needed on longer runs

Never connect a 12V strip to a 24V power supply or vice versa — always match the strip voltage exactly to the driver output voltage. Lumily LED strips are clearly labelled 24V — pair them with a 24V constant-voltage driver.

What Is LED Forward Voltage?

Forward voltage is the minimum voltage required to allow current to flow through an LED and cause it to emit light. For a single LED chip, this is typically around 2V to 3.5V depending on the colour. In a strip light, multiple LEDs are connected in series within each cut section — the strip is engineered so that the total forward voltage across each section matches the rated supply voltage.

You do not need to calculate forward voltage manually when using Lumily LED strips — it is accounted for in the product specification. What matters is matching the supply voltage to the strip and ensuring your driver delivers the required wattage.

How to Calculate the Right Power Supply

Power supply sizing formula
1
Find the wattage per metre (W/m) in the product specification
2
Multiply by total run length in metres — e.g. 4m × 14W/m = 56W
3
Add 20% headroom — multiply by 1.2: 56W × 1.2 = 67.2W
4
Round up to the next available driver size — e.g. 75W or 100W
5
Confirm driver voltage matches your strip — all Lumily strips are 24V
Example: 8m run at 10W/m = 80W. Add 20% = 96W. Choose a 100W 24V driver.

Do LED Strips Run Off AC or DC?

LED strips run off DC (direct current). Your mains supply is 230V AC. The driver converts AC mains to the correct DC voltage — this is why a driver is always required.

Never connect an LED strip directly to the mains supply.