Speedsim

Speedsim is not a cheat, and you are most likely a noob if you haven't heard of it. There's also DragoSim but I don't care much about it lol.
So what is Speedsim: it's a combat simulator. You just enter then number of attacker's and defender's ships or defense, press calculate and see who wins the battle. Simple as that. Here's your download link.
It also supports inputing spy reports from clipboard, it can calculate the speed of your fleet and deuterium costs at various speeds. A whole bunch of features and it's all free.