Good design can be the difference between steps being easy to use or hazardous. When designed properly, stairs are easy to walk up and down because you don't have to think about every step. But when steps are uneven, they can cause accidents.
Determine where to put the steps. You may need to level the ground at the base.
Measure from the ground to the bottom of the back door in centimetres. Subtract 5 cm if the door opens outwards.
Divide your measurement by 17.5. This will tell you the number of steps required to make the correct height. 17.5 cm (7 inches) is the maximum height of steps allowed under most building codes.
Multiply by 27.5. Twenty seven and a half centimetres (11 inches)is the minimum width for stair treads under most codes. This will give you the total projection of the steps from the building.
Add the measurement for any extra projection, such as a landing at the top of the stairs.
Make sure to check with local planning department for planning permission requirements prior to construction.