Add

You'd think adding two numbers would be the most boring node in existence, and you'd be mostly right. But UC_MathAdd from silveroxides' ComfyUI-UtilsCollection is the version you actually want: it's not stuck at two inputs. Connect as many numbers as you like and it folds them together left to right. One node, one result, no daisy-chaining five adders.

Why you'd reach for it

Anywhere a computed value is the sum of several things. The classic is layout math: base resolution plus a margin plus an offset, or a latent's pixel budget built from width + padding + a step count. It also earns its keep in parametric workflows where you've converted widgets to inputs - one UC_MathAdd with a bunch of wires beats a stack of two-input adders for legibility, and legibility is half the battle in a graph with forty nodes. As the node-plumbing essay in our knowledge base points out, utility nodes like this exist to fight repetition and illegibility, and the multi-input adder fights both.

How it works

The input is an "autogrow" socket: operands, which you can extend from 2 up to 10 connections by dragging in more wires. The node iterates them left to right, applying + in order, so order doesn't matter for addition but the habit of reading left-to-right carries over to the sibling nodes where it does. The output is typed by MatchType, meaning int plus int gives an int, and the moment any operand is a float the result is a float. That's usually what you want, but it's worth knowing before you wire a sum into a strictly-INT socket and get a type mismatch.

The input that matters

Just operands. Add as many as you need. There's no handle_zero or mode dropdown - it's as plain as the operation it wraps.

Installing it

Part of ComfyUI-UtilsCollection. ComfyUI Manager → search "ComfyUI-UtilsCollection" → Install → restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/silveroxides/ComfyUI-UtilsCollection

Restart after. The only requirements are opencv-python and typing-extensions, and there are no model downloads to worry about for the math nodes.

Where people get tripped up

The two recurring surprises: first, the autogrow socket confuses people who've never seen one - if you don't see enough inputs, just drag another wire onto the socket and it grows. Second, if you're migrating from the old ComfyUI-LogicMath pack, this node (and its siblings) is its replacement. ComfyUI will prompt you to swap old LogicMath nodes for these; say yes, then uninstall LogicMath, because running both is how you end up with duplicate node menus. It's a simple node, but it's a genuinely good one - the one you'd reach for over a formula hack in most workflows.