A quick rule of thumb with steps. 7 inches in height is the goal, but since that's usually impossible, getting as close to 7 inches is the reality. Every step needs to be within a quarter inch of each other. A friend was sued over the steps being at different heights when a renter was injured from a fall. If my memory is correct, I think there was half an inch difference in each step, and it wasn't consistent, with some being more then seven inches, and some being less then seven inches.
A 2x6 on edge with another 2x board on the flat is the perfect height for steps.
When walking through a door, from the inside of a house, or building, to an area with steps, the top step, or landing, should be at the same height, or just under, the height of the interior floor. It's not uncommon to see the outside step be a full step down from the interior, and it's not uncommon for people to get used to it over time, but if an injury occurs from those steps, the home owner will be the one getting sued by the injured persons insurance because of the unsafe nature of those steps.