How to make a mob bigger?

if its a pre-set model its impossible, I learned the hard way. if its custom model then size the model bigger, problem solved

but how do you do that?

you have to be more specific when asking your question or else no one can help you.

are you making en entity with a custom model you made, or are you using any of the preset minecraft models?

To make a big mob I suggest using blockbench where you can make your own entity models.

I using any of the preset minecraft model how to change entity model size

So you can't use a preset model. But try getting Blockbench, it has no viruses and it's totally free. Then, start making a minecraft skin but at the start, it'll show you your model is Steve. Just change that to whatever model you want by clicking on it. Then, start the project. Straight after, go to file and click convert project. Then convert it to a java entity. Now you just have to change the numbers with the x y z and stuff. Multiply it by however much bigger you want it. When you're done, just export java entity by clicking file. Not save as, Export entity. And uh, I suggest making your hitbox small because big hitboxes produce lots of lag XD. And the skin for the mob might glitch, and if it does, all you have to do is change the size of the texture back in blockbench.