Model exactly how much voltage is lost over a wire run, and find out where to inject extra power to fix it.
Select a common strip/voltage combination, or enter your own voltage, current draw, and LED density for a non-standard setup.
Strip length is the total run of LEDs. Wire length is the distance of copper wire between your power supply and the point being measured — these are often different, especially with extension cables.
Thicker wire (lower AWG number) has less resistance and less voltage drop. If you don’t know your wire gauge, it’s usually printed on the wire jacket or in the product listing.
Voltage drop is worse at higher brightness because more current is flowing. Set this to the realistic brightness you’ll run, not just 100%, for an accurate real-world figure.
Enter how many extra power injection points you plan to add along the strip, and where. The calculator recalculates voltage at the far end based on this, showing you how injection improves the result.
The result shows the actual voltage arriving at the end of your run. Anything below roughly 4.5V on a 5V strip (or proportionally low on 12V/24V) will cause visible colour shift and dimming — add injection points until the result is acceptable.
Voltage drop is one of the most common causes of "my LEDs are dim/wrong colour at the end of the strip" — if you’re troubleshooting that exact symptom, this tool will show you precisely why it’s happening.
The Voltage Drop Calculator should be used after the Power Calculator for any LED strip run longer than 2–3 metres. It tells you whether your voltage at the far end of the strip is within tolerance, and gives you a concrete power injection plan if it is not.
Use the same strip type and total run length as in the Power Calculator. The calculator uses the strip's copper trace resistance per metre alongside your wire resistance to model voltage at each point along the run.
Select the AWG gauge of the wire you plan to use for the power feed. Lower AWG = thicker wire = lower resistance. Start with the minimum gauge recommended by the Power Calculator, then check whether the voltage drop result is acceptable. Increase wire thickness (lower AWG) if the far-end voltage is too low.
The result shows the voltage arriving at the midpoint and far end of your strip. For 5V strips, the far end must remain above 4.5V. For 12V strips, above 11.4V. If the far-end voltage is below tolerance, add power injection points at the spacing shown in the injection plan.
The injection plan shows how many power feed connections you need and at what intervals. Each injection point requires running a pair of wires (positive and ground) from your power supply terminal block directly to that point on the strip. The total cable run for injection points should use the same gauge as your main power feed.