It should be big enough, depending on how many rats you have - you can check using an online cage calculator
I don't think you will be happy with the cage
If you are in the USA, you might want to consider a martins powder coated R695 with flip top lid
- you have to cover the wire floors and use zip ties to assemble because the c-rings that come with it will rust, but it is a good cage for rats (martinscages.com)