How to Measure And Build Stairs

Learning how to make a precise and beautiful stairway seems challenging, but it's really quite simple if you use the proper formula. This is how you can measure and build professional-looking stairs with exact accuracy.

Measure And Build Stairs
  1. Before you can start putting up the stairs, you'll need to take a few measurements. You need to think of it this way: there is so much height that needs to be reached and it has to be done within a certain length.

  2. The part of the stairs that will help us accomplish the height is the risers. The length part is the treads. The part of the stairs that will hold all the weight will be the stringers.

  3. The treads are usually around 10-inches. That's kind of standard, but the risers completely depend on the height from the bottom floor to the top floor. Get an exact measurement from the bottom floor to the second floor, including the second floor particle board.

  4. Use the formula for getting the height of each stair riser.

  5. Suppose the distance from the bottom floor to the top floor including the thickness of the second floor is 108 inches. 108 divided by 7 equals 15.428. That tells us that 15 risers will be needed.

  6. Next, divide 108 by 15 and you'll get right around 7 inches or the exact height of each riser. The treads need to be right around 10 inches.

  7. The amount of treads will be one less than the amount of risers, so to find the total run or length of the stairs, we just multiply 10 (treads) by 14 (risers) and that tells you that our stairway will be 140 inches long.

  8. Select a knot-free 2 X 12 stringer. Get prefabricated wood or a cheaper selection might be a strong softwood like Fir or Pine. It needs to be about one foot longer than the stair distance. In our example it would need to be 120 inches or twelve feet long.

  9. Next, while the board is laying flat, measure up about 8 inches to mark the first stair tread. Use a carpenter's square to measure 10-inches over(tread) and 7-inches up(riser). Do this on every step. Once that is done, go back to the bottom of the board and measure and cut the first riser. Use the carpenter's square to make it exactly 7 inches.

  10. Once this is all marked, cut out the stairs with a circular saw. Cut almost to the inside corner, but complete the cut with a hand saw to get into the corners. When that's done, use it as a pattern for the other stringers by tracing in the steps.

  11. Stand them up and secure them with nails or screws. Once the stringers are in place, put the tread plates on and then the riser plates.

  12. You can buy special tread boards that are rounded on the front. They work nicely for carpeted stairs. If you want to have hardwood stairs that are exposed, use high quality oak or some other hardwood.

  13. Tip

    Steps wider than 36 inches will need a stringer in the center for more support. Be sure to get help when standing up the stringers. Stairs with landings are measured and built as two stairways.


    Please use caution when working with circular saws. Use eye protection while sawing.