How to Calculate Number of Riser and Tread for a Staircase Steps?

Another little confusing task in construction is calculating the number of steps for a staircase.

Apart from the Septic tank and water tank size calculation one of the mind-blowing thing in building construction is staircase design.

It is simple & easy when you understand the method of calculation and now we are going to discuss the staircase step design calculation.

Minimum Specification

• The maximum height of riser should be 150 to 200 mm.
• The minimum tread length should be 250 to 300 mm.
• Length of the step should be a minimum of 600 mm.
• The handrail height should be a minimum of 1 metre.
• The width of the landing slab will be at least 1000 mm for the walkover on the staircase.

Staircase Design calculation –  Example

Now we are going to calculate the required number of Riser and Tread for a Dog legged staircase having

• 3-metre height
• 4-metre width
• 1-metre width of landing slab

Staircase Dimension Calculation Formula

Number of Riser = Height of Staircase/ Height of one number of Riser

Number of Tread = Length of Stair/One number of Tread

From the above Diagram,

The staircase has divided into two flights providing a landing slab at mid of the staircase height.

So Number of Riser = Height of Staircase / Height of one Rise

                                  = 1500/150

                                  = 10 Nos

So as per standard, we are providing 300 mm as tread length.

Number of Tread      = Length of Stair/One number of Tread

                                  = 3000/300

                                  = 10 Nos

Hence the required number of Riser and Tread is 10 Nos.

IMPORTANT NOTES

The tread and rise size will be change as per the usage.

You may see the height of the riser will be provided as 100 mm or 120 mm in the railway station and hospital building staircase.

Since senior citizens and sick people are using the staircase at the locality, the riser and tread size may be decreased for their convenience.

Staircase Calculator

You may calculate the length and height of the tread or rise of the staircase by using the following calculator.

You may interest to read the Concrete Material Estimation.