Azzebo has it right. The only thing you ever count the front rank for is Steadfast, so if a unit has 5 models they count as 1 ranks, where a monster fighting them (or a skirmish or fast cavalry unit) counts as 0 ranks. Those 5 models would be Steadfast.
_________________ I made the move to professionally painting 3 years ago. I paint a good mix between speed and quality. This keeps prices low, like a typical 2K 40k army is under $500.