What is larger 0 AWG or 4 AWG?

the lower the number, the larger the wire. 0 AWG is larger than 4 AWG

More information:

The above answer is correct but I wish to add more information. What you are calling 0 AWG is usually written as 1/0 and called "one ought". From there the numbers get larger: 1/0, 2/0 (read "2 ought"), 3/0, and 4/0. From there wires are written in there MCM size or kcmils (kilo-circular-mills) which stands for thousand circular mills, the same as MCM. That's a lot of useless information unless you are a competent electrician. I just wanted to clarify that 0 AWG is commonly called 1/0, or "one ought."