Addressable LED strip pixel and DMX universe calculator
Pixel strip is budgeted three ways at once: pixels and channels for the control system, frame rate per data chain, and watts per feed for the power. Enter the runs and the model and the list comes back with all three.
Runs to pixels, universes and feeds
One pixel per cut segment on the COB and DMX rows, one per LED on the SK6812 rows, as the spec tables mark them. The IC decides refresh, data lines and how far data jumps between sections.
What the numbers mean, and what they leave out
-
01
Pixels and channels
Pixels are the run length divided by the pixel pitch, rounded up. Channels are pixels times colors: three for RGB, four for RGBW, five for RGBCW. Both go on the drawing before a controller is chosen.
-
02
SPI frame rate
One data chain at 800 kbps spends 1.25 µs per bit plus a short reset per frame, so a 24-bit pixel costs 30 µs. The frame rate of the whole chain follows, and 30 fps is the floor for moving content; longer chains are split across outputs.
-
03
DMX universes
A universe is 512 channels: 170 RGB pixels, 128 RGBW, 102 RGBCW. Each universe is one output from a console or node, and each chain on it is terminated.
-
04
Power is separate
Data runs through the strip; power does not. Feed points follow the model's run limit per feed, and the connected load goes to the power supply calculator. Grounds of every supply on a data chain are tied together.
The guides behind the numbers
WS2811, WS2814, WS2818 or SK6812? Pick the Pixel IC by the Job
SPI vs DMX Addressable LED Strip: Wiring, Distance, and Failure Modes
A DMX Universe Fits 128 RGBW Strip Zones; One Chain Takes 32
Why Does the Far End of an LED Strip Go Dim?
How to Size an LED Strip Power Supply, From Watts to Class 2 Limits
LED Strip Wiring Diagrams, From Two Wires to Five
Reading the budget
Why is the pixel count higher than the LED count divided by three?
On COB rows the IC drives a small group of LEDs and the cut marks sit between groups, so the pixel pitch is the cut unit, not three LEDs. On the SK6812 SMD rows every LED package is its own pixel. The calculator applies the rule per row; confirm the pitch on the datasheet before the final address map.
What frame rate do I need?
About 30 frames per second for chases and video content; slow color washes get by with less. When one chain falls under the target, split it across controller outputs rather than slowing the show.
Can one DMX universe serve several runs?
Yes, if the runs are on the same data chain and the addresses do not overlap. Runs that cannot be chained physically need their own output, so count outputs as well as universes.
Does the data distance limit the run length?
No. Data is regenerated at every pixel, so a continuous run can be as long as the frame rate allows. The limit applies to gaps without pixels: controller to first pixel, column wraps, doorways. Keep them inside the IC's rated reach or add a repeater.
Why does the power still need feeds every 16 ft?
Because the strip's copper carries the current, and the model's run limit per feed is set by that, whether the data is SPI or DMX. A 200 ft chain on one controller output is still fed with power about every 16 ft, with the grounds tied.
Send the layout and we schedule the outputs
Runs, jumps and the control system you have in mind are enough. An engineer replies with the model, the output and universe schedule, the feed points and the parts list, in writing.
- 1 reel minimum
- Drawings welcome
- US-based support