Now some math:
1. Find Number of Rises
Divide Overall Height by 7 (OVERALL HEIGHT / 7 = ????)
Whatever number you come up with will be followed by decimals. Drop the decimals. Keep the whole number. This is your number of RISES.
So in my example, my overall height is 16". 16 / 7 = 2.2857.... I drop the decimals and we know we need 2 rises.
2. Find Height of Rises
Now we know the overall height of all rises and the number of rises, now we just need to find the height of each rise. Take your Overall Height and divide by your number of rises.
In my example, my overall height is 16" and we have two rises. 16 / 2 = 8. Each rise will be 8".
3. Determine Tread Widths.
For us it doesn't matter where the stairs come out, so we pick 11" as our tread width (that's 2 - 2x6s and a little nosing). If your stairs must come out at a certain spot, find your overall desired run length, divide by the number of treads, and that's how you would figure your tread width. Keep in mind what material you will use for your treads.