Add

Addition is the least interesting node in any pack, so let's be honest about what this one is for: it's a four-input adder that doesn't make you care about types. Most math in ComfyUI forces you to match INT to INT and FLOAT to FLOAT or the wire won't connect. This node has two float inputs and two int inputs, and it just adds whatever you feed it together - the sum comes out as both an INT and a FLOAT, so either kind of downstream field will take it.

It's from the Utilitools pack, a small personal collection by one author with no dependencies and no model files. Every input here is optional: float_a, float_b, int_a, int_b, each defaulting to 0. That's actually the useful quirk. Because unconnected inputs silently contribute 0, you can wire up just the two you need and ignore the rest - it degrades gracefully from a 4-input adder down to a 2-input one without you doing anything.

How it works

The mechanism is one line: add all four values, return the total as an int and as a float. The int output truncates toward zero if the result has a fractional part - so 1.5 + 1 gives you 2 on the int side and 2.5 on the float side. If you only care about whole numbers, grab the int output; if you're chaining into something that accepts decimals, grab the float.

Where you'll actually use it: nudging a resolution up (width + 64), offsetting a seed, adding a constant to a step count, or summing values from two different sources without adding a conversion node in between. It's glue - you use it because it's one box instead of two.

What to watch for

Because all four inputs are optional and default to 0, a fully disconnected Add node just outputs 0. That's fine, but it means the node won't warn you when you forget to wire something - you'll just get a smaller sum than you intended. It's worth a glance when your math comes out suspiciously low. The other thing: there's no overflow protection, not that you'll hit it with any number a sampler accepts. And for anything beyond addition - division, percentages, order-of-operations expressions - the pack's Calculator node is the better tool; this one is strictly "sum the inputs."

Installing it

Search "Utilitools" in ComfyUI Manager, or:

cd ComfyUI/custom_nodes
git clone https://github.com/aesethtics/ComfyUI-Utilitools

Restart ComfyUI and it's under Utilitools → Math. No requirements.txt, nothing to download - the whole pack is stdlib Python, so there's no dependency hell waiting for you. It won't change your life, but when you need a sum in the middle of a graph, it's the one box that does exactly that.