NeoPixel Power Calculator
Total number of individually addressable pixels in your installation
Operates at 5V supply voltage
PWM brightness — power scales linearly (50% brightness = ~50% power)
Enter Your LED Configuration
Set your LED count, type, brightness, and color above to calculate total power draw, PSU size, wire gauge, voltage drop, and code snippets.
How to Use the NeoPixel Power Calculator
Enter Your LED Count or Strip Length
Switch between 'LED Count' mode (enter the total number of pixels) or 'Strip Length' mode (enter length in meters and choose density like 30, 60, 96, or 144 LEDs per meter). The calculator converts strip length to a pixel count automatically.
Select LED Type and Adjust Color
Choose your LED chip type from the dropdown — WS2812B, SK6812 RGBW, WS2811, APA102, etc. Then set brightness with the slider and pick a color preset or move the R/G/B sliders to match your intended usage. The color swatch updates live and the donut chart shows how each channel contributes to total power.
Review PSU and Wire Results
Check the PSU Recommendation card for minimum wattage and amperage including your safety margin. The Wire and Voltage Drop card shows the minimum recommended AWG wire gauge, calculated voltage drop across your feed wire, and flags any run exceeding the 5% threshold. Open Advanced Options to enter your feed wire length and current gauge for accurate drop numbers.
Copy Code Snippets and Export
The Code Snippets card generates ready-to-paste FastLED and Adafruit NeoPixel library lines with your exact voltage and current limits pre-filled. Copy and paste them directly into your sketch. Use the Export CSV button to save all inputs and results, or Print Results for a clean printable summary.
Frequently Asked Questions
Why does the calculator use 60mA per WS2812B LED instead of 36mA?
The calculator defaults to the original WS2812B datasheet value of 20mA per channel (60mA full white) for conservative, safe PSU sizing. Community measurements and the newer v5 datasheet show 12mA per channel (36mA full white) for modern WS2812B chips. We recommend sizing your PSU for the worst case (60mA) and using FastLED's setMaxPowerInVoltsAndMilliamps() to cap actual draw at the measured level. If you have confirmed v5 chips and want a tighter estimate, select 'WS2812B v5 (measured avg)' in the LED type dropdown.
How do I know if I need power injection?
Power injection is needed whenever total strip current exceeds about 4 amperes from a single feed point. At 5V with WS2812B, that's roughly 66 LEDs at full white brightness. The calculator automatically computes the number of injection points based on your total current and shows suggested spacing. Visible signs that injection is needed include pixels at the far end of the strip appearing dimmer or slightly different in color than pixels near the power feed — most noticeable at full white or high brightness levels.
What wire gauge should I use for my NeoPixel strip?
The recommended wire gauge depends on your total current draw and feed wire length. For short runs under 0.5m, 22 AWG is usually sufficient up to 3A. For runs of 1–2m at 5A, use 18 AWG. For longer runs or higher currents, go to 16 AWG or thicker. 5V systems need heavier wire than 12V systems at equivalent power because they carry more current. Use the Advanced Options in this calculator to enter your wire length and gauge and see the exact voltage drop in volts and percentage — keep it below 5% (0.25V on a 5V supply).
Why does my color change when the strip runs at full brightness for a long time?
Color shift during sustained full-brightness operation is caused by voltage drop along the strip's internal copper traces and your feed wires. As the supply current increases (due to warming, for example), ohmic resistance causes the voltage at distant pixels to fall below nominal. Blue LEDs have a higher forward voltage than red LEDs and are more sensitive to supply voltage drops, so they dim more noticeably than red — producing a warm tint at the far end of the strip. Adding power injection points or reducing brightness eliminates this effect by distributing current load more evenly.
What safety margin should I use for my PSU?
We recommend a 20% safety margin for typical indoor, ambient-temperature installations. This means the calculator recommends a PSU rated at 120% of your calculated load, keeping the supply running at roughly 83% of maximum — within the standard guideline of not exceeding 80% continuous load. Use 25–30% margin for outdoor installations, high-duty-cycle animations that run at high brightness for many hours continuously, or installations in warm environments where PSU derating applies. Never run a PSU at 100% rated load continuously; it shortens component life and increases fire risk.
Can I use FastLED's power limiting to avoid oversizing my PSU?
Yes, FastLED's setMaxPowerInVoltsAndMilliamps() function is an excellent safety net. It monitors calculated power draw each frame and automatically reduces global brightness just enough to stay within your specified limit — similar to a software-controlled current limiter. This allows you to run a smaller PSU intentionally, knowing the software will cap brightness before tripping the supply. The code snippet this calculator generates pre-fills your voltage and a conservative milliamp limit based on your inputs. However, this approach still requires your PSU to handle the cap limit continuously, so size it accordingly.