NeoPixel Power Calculator
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.
Calculate power, current, PSU size, wire gauge, and voltage drop for addressable LED strips
Planning a NeoPixel or addressable LED strip project requires careful power budgeting. Undersizing your power supply causes voltage sag, color inaccuracy, and even hardware damage. Oversizing wastes money and generates unnecessary heat. This NeoPixel Power Calculator gives you precise current draw, wattage, recommended PSU specs, safe wire gauge, voltage drop, and power injection point counts for any WS2812B, SK6812, WS2811, WS2815, WS2813, or APA102 strip — all in seconds. Addressable LEDs are deceptively power-hungry. A single WS2812B LED can draw up to 60 milliamps at full white (all three color channels at maximum, 5V supply). Multiply that by 300 LEDs on a standard 5-meter strip and you're looking at 18 amperes worst-case — nearly 90 watts from a 5V supply. Real-world usage is typically much lower: animations, rainbow effects, and partial-brightness modes commonly consume 20–30% of the maximum draw. But your power supply must handle the worst case, not the average. This calculator supports multiple LED types with accurate per-channel current data gathered from manufacturer datasheets and independent community measurements. WS2812B LEDs come in two common variants: the original datasheet specifies 20 mA per channel (60 mA full white), while the v5 datasheet and community measurements typically show 12 mA per channel (36 mA full white). We default to the conservative 20 mA/channel value for safe PSU sizing. SK6812 RGB LEDs draw around 8 mA per channel at full brightness, making them noticeably more efficient than WS2812B. The SK6812 RGBW variant adds a dedicated white LED channel drawing approximately 16 mA — handy for warm white effects without color mixing artifacts. Voltage and wire gauge are closely linked in LED installations. The 5V systems used by most NeoPixels require much heavier wire than 12V systems for equivalent power delivery, because current is inversely proportional to voltage at the same wattage. A 5V strip drawing 5A needs 18 AWG or heavier wire for a 1-meter feed run, while a 12V system at the same wattage only draws 2.1A and can use 22 AWG wire. The calculator shows your voltage drop across the feed wire using Ohm's law, flags runs exceeding 5% drop, and recommends the minimum AWG for safe continuous current. Long LED strips need power injection — feeding power into multiple points along the strip rather than only from one end. The copper traces inside LED strip PCBs have finite resistance. When high current flows through them, you get a progressive voltage drop from the power-feed end to the far end. Pixels at the far end appear dimmer and slightly different in color from pixels near the feed. As a guideline, inject power at least every 50 LEDs at full brightness, or every 100–150 LEDs at 50% brightness. The calculator tells you the minimum number of injection points based on your total current draw and shows ideal spacing for uniform power distribution. The RGB color sliders let you dial in your exact color mix and see how it affects power consumption in real time. Full white (R=255, G=255, B=255) is the worst case. Red-only, green-only, or blue-only modes draw one-third of full white. The live color swatch shows the approximate color your strip will display. A donut chart breaks down power consumption by channel so you can see at a glance which color is driving your power budget. For embedded developers, the calculator generates ready-to-paste FastLED and Adafruit NeoPixel library code snippets. FastLED's setMaxPowerInVoltsAndMilliamps() function automatically throttles brightness to stay within your supply's rated current — a critical safety feature for battery-powered or supply-limited projects. The Adafruit setBrightness() function scales all pixel output without changing individual color values. Safety margin matters. Running a power supply at 100% of its rated output continuously causes premature aging and overheating. Most quality PSU manufacturers recommend loading to 80% maximum for continuous duty. The calculator defaults to a 20% safety margin, meaning it recommends a PSU rated at 120% of your calculated load. You can adjust this from 5% to 50% depending on your duty cycle and environment — use higher margins for outdoor installations or high-duty-cycle animations.
Understanding NeoPixel Power Requirements
What Are NeoPixel and Addressable LEDs?
NeoPixel is Adafruit's brand name for WS2812B-based addressable RGB LED products, but the term has become a generic nickname for any individually addressable LED that integrates its control IC directly into the LED package. Each pixel contains a red, green, and blue LED die plus a tiny PWM driver chip that receives data on a single wire, stores the RGB value, and drives the LEDs accordingly. Modern variants like SK6812 RGBW add a fourth dedicated white LED channel. Strips are available in densities from 30 to 144 LEDs per meter and operate on 5V or 12V depending on the model. The integrated control chip requires a small quiescent current even when all color channels are off — typically 0.2–1 mA per pixel — which contributes meaningfully to standby power in large installations.
How Is Power Consumption Calculated?
Per-LED current is calculated by summing the fractional contribution of each color channel based on the PWM duty cycle. For a WS2812B at R=128, G=64, B=255 and 80% brightness: current = (128/255 × 20mA + 64/255 × 20mA + 255/255 × 20mA) × 0.8 + 0.5mA quiescent. Strip total current is this value multiplied by the number of LEDs. Power in watts equals total current (in amps) times supply voltage. Voltage drop across feed wires is calculated with Ohm's law: ΔV = I × R_wire × length × 2, where the factor of 2 accounts for both the positive and ground conductors. PSU recommendation applies a safety margin multiplier (default 20%) to the calculated wattage and amperage.
Why Does Proper Power Planning Matter?
Underpowered LED installations cause three distinct failure modes. First, voltage sag: when total current demand exceeds supply capacity, voltage drops below nominal, causing LEDs to display incorrect colors (red and green channels shift relative to blue, which has a higher forward voltage). Second, pixel glitches: low supply voltage causes WS2812B data protocol timing errors, resulting in flickering, wrong colors, or frozen pixels. Third, hardware damage: drawing sustained current beyond a PSU's rating causes overheating, capacitor wear, and shortened life. Conversely, correct voltage drop management on long runs prevents the characteristic 'warm end cool end' problem where pixels near the power feed are brighter than distant pixels.
Limitations and Caveats
This calculator uses conservative datasheet values for power calculations. Real-world current draw varies by manufacturer batch, temperature, and supply voltage accuracy. The '20mA per channel' WS2812B figure represents the original 2012 datasheet; many modern WS2812B chips (especially v5 revision) measure closer to 12mA per channel at full brightness. Use the WS2812B (v5 measured) option if you have confirmed v5 chips and want a tighter estimate. Wire voltage drop calculations assume solid or stranded copper wire at room temperature — aluminum wire, poor connections, or high ambient temperature all increase effective resistance. Power injection spacing is a guideline; actual visible color shift depends on brightness level, strip age, and trace quality.
Formulas
Current for one LED in milliamps, where R, G, B are color channel values (0–255), I_r/I_g/I_b are the per-channel max current from the datasheet (e.g., 20 mA each for WS2812B), brightness is a 0–1 scalar, and I_quiescent is the idle current (~0.5 mA).
Total power consumption in watts, where I_led is the per-LED current in milliamps, N_leds is the number of LEDs, and V_supply is the supply voltage (5V or 12V). Divide by 1000 to convert milliamps to amps.
Voltage drop in volts across the feed wire, where I_total is total current in amps, R_wire is resistance per meter for the wire gauge (from AWG tables), L is one-way wire length in meters, and the factor of 2 accounts for both positive and ground conductors.
Recommended PSU wattage, where P_total is the calculated total power and margin is the safety percentage (default 20%). Running a PSU at 80% of rated capacity extends its lifespan and prevents overheating.
Reference Tables
Addressable LED Type Specifications
| LED Type | Voltage | Max mA (Full White) | mA per Channel | Notes |
|---|---|---|---|---|
| WS2812B (datasheet) | 5V | 60 | 20 | Conservative value for PSU sizing |
| WS2812B (v5 measured) | 5V | 36 | 12 | Community-measured; modern chips |
| SK6812 RGB | 5V | 24 | 8 | Lower power; good for battery projects |
| SK6812 RGBW | 5V | 40 | 8 (RGB) + 16 (W) | Dedicated white channel |
| WS2811 | 12V | 54 | 18 | External driver IC; 3-LED groups |
| WS2813 | 5V | 60 | 20 | Dual data line for fault tolerance |
| WS2815 | 12V | 60 | 20 | 12V with single data line |
| APA102 / DotStar | 5V | 60 | 20 | SPI data + clock; high refresh rate |
Recommended Wire Gauge by Current
| Total Current (A) | Max Run (m) at 5V, <5% drop | Recommended AWG | Wire mm² |
|---|---|---|---|
| 1–2 | 3.0 | 22 AWG | 0.33 |
| 2–4 | 2.0 | 20 AWG | 0.52 |
| 4–6 | 1.5 | 18 AWG | 0.82 |
| 6–10 | 1.0 | 16 AWG | 1.31 |
| 10–15 | 0.8 | 14 AWG | 2.08 |
| 15–20 | 0.5 | 12 AWG | 3.31 |
Worked Examples
5-Meter WS2812B Strip at Full White
Total LEDs: 5 m × 60 LEDs/m = 300 LEDs
Per-LED current (full white): (255/255 × 20 + 255/255 × 20 + 255/255 × 20) × 1.0 + 0.5 = 60.5 mA
Total current: 300 × 60.5 mA = 18,150 mA = 18.15 A
Total power: 18.15 A × 5V = 90.75 W
PSU with 20% margin: 90.75 × 1.20 = 108.9 W → use a 120W / 24A 5V supply
SK6812 RGBW Strip at 50% Warm White
Total LEDs: 2 × 60 = 120 LEDs
Per-LED current: ((200/255 × 8) + (140/255 × 8) + (50/255 × 8) + (180/255 × 16)) × 0.50 + 0.5 mA
RGB channels: (6.27 + 4.39 + 1.57) × 0.5 = 6.12 mA
White channel: (11.29) × 0.5 = 5.65 mA
Per-LED total: 6.12 + 5.65 + 0.5 = 12.27 mA
Strip total: 120 × 12.27 = 1,472 mA = 1.47 A
Power: 1.47 × 5 = 7.36 W
Voltage Drop on a 3-Meter Feed Wire
18 AWG copper resistance: 0.02095 Ω/m
Voltage drop: ΔV = 9 A × 0.02095 Ω/m × 3 m × 2 = 1.13 V
Drop percentage: 1.13 / 5.0 × 100 = 22.6%
This far exceeds the 5% (0.25V) threshold
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.