How To Calculate Slope Of Staircase

Step 1:
Measure the distance of treads (Exclude the width of nosing). If all the treads are uniform in size, measure one tread otherwise you will need to measure all treads.
Let the width of tread = 250 mm.
Step 2:
Measure the height of risers. If risers are all uniform in size measure only one. If they are different sizes you will need to measure all risers.
Let the height of riser = 150 mm.
Step 3:
Divide the riser height by the tread width and then calculate the inverse tangent.
tanθ = Riser Height/Tread Width = 150/250 = 0.6
∴ θ = tan−1 0.6 = 31°

Keep in mind that tread and riser of uniform size ensure easy measurements and more accurate results. I advise you to build a staircase that it’s slope is not too steep or steep enough (Staircase slope between 30° to 40° is considered as standard).