Issue 64 Tread and Rise Combinations Chart

StepsWhat size steps? Steps are made up of the tread, which is the part you step on, and the step rise, which is the part you trip on! It’s important to have the right ratio of tread to rise to make going up and down safe and easy. In general, the smaller the rise, the bigger the tread. For the most part you should choose what’s comfortable for you but usually outdoor steps have a rise of 5 1/2 to 7 inches and a tread of 12 to 18 inches. Once you find a ratio you think will be comfortable for you, plug it in and tweak it until it fits this formula: Step tread + (2 × riser) = 26 or 27 Or use this handy chart below with the ratios already figured for you. You’ll find the tread width in the column on the left and the rise height in the column on the right. You’ll notice an 18 inch tread can have either a 4 or 4 1/2 inch rise — each fits the equation so the choice is up to you.
Step tread + (2 × riser) = 26 or 27 inches
Step tread Step riser
18 in. 4 in.
18 in. 4 1/2 in.
17 in. 4 1/2 in.
17 in. 5 in.
16 in. 5 in.
16 in. 5 1/2 in.
15 in. 5 1/2 in.
15 in. 6 in.
14 in. 6 in.
14 in. 6 1/2 in.
13 in. 6 1/2 in.
13 in. 7 in.
12 in. 7 in.
12 in. 7 1/2 in.