Papcorns - FPS Calculator

This is the honest one. Papcorns - FPS Calculator is a node that takes a frame count, divides it by a video length, and hands you the FPS as a float. That's the whole job. It's not going to change your life, but when you're assembling a video workflow it solves a genuinely annoying recurring step, so it's worth knowing it exists.

Why you'd want a division as a node

Video workflows in ComfyUI are picky about frame rate. VHS SaveVideo and the various video-combine nodes want an fps value, and if you're chaining chunks - say you generated 81 frames of Wan at 16 fps and want to merge it with another 81-frame chunk - you either do the mental math every run or you wire a fixed number in and hope nothing changes. The Papcorns node turns that into the graph: feed it frame_count and video_length and the fps floats out of the other side, ready to plug straight into a Save Video or video-assembly node. If you later bump the frame count, the fps updates with the graph instead of you editing a constant and praying.

The two inputs, the one output

• frame_count - total frames, default 30, up to 999999.
• video_length - the clip length in seconds, default 1, up to 86400. This matters: it's seconds, not frames. Confusing this is the classic footgun.
• Output: FPS (a FLOAT), computed as frame_count / video_length.

That's the entire schema. There's a zero-division guard that returns 0.0 and a debug line printed to your console, and nothing else. It's a utility node: no image passes through, no state, no side effects.

Install

It's part of the Papcorns pack, so you get it with the family:

cd ComfyUI/custom_nodes
git clone https://github.com/papcorns/Papcorns-Comfyui-Custom-Nodes
cd Papcorns-Comfyui-Custom-Nodes
pip install -r requirements.txt

Restart ComfyUI (or use Manager and search "Papcorns"), and it appears under the Papcorns🍿 menu.

The honest take

Do you need this? If you already keep a Math Expression or calculation node in your toolbar, you have this functionality and don't need a second home for it. But if you're new to video in ComfyUI and don't want to reach for a general-purpose math node every time you want "frames ÷ seconds," this is a clean, zero-risk single-purpose node - the kind that's too trivial to be exciting and too convenient to argue with. Pair it with the length your video chunk actually is, wire the float into your Save Video fps slot, and move on. LTX and Wan workflows both lean on these fps numbers constantly, and having the graph tell you rather than you telling the graph is genuinely nicer.

One caveat worth repeating since it's a small personal pack: there's no validation beyond the division, so if you feed it a frame count and a length that don't correspond to a real clip, you'll get a plausible-looking number that's still wrong. Garbage in, a cleanly formatted garbage float out. The node computes; it doesn't check.