Calculate the number of risers and treads, the actual riser height, and the total horizontal run needed for a staircase between two floors.
How to Use the Staircase Calculator
Enter the "Total Rise" - the vertical floor-to-floor height in millimeters.
Enter your "Desired Riser Height" - typically 150-190mm.
Enter your "Desired Tread Width" - typically 250-300mm.
Click "Calculate Staircase" to see the number of risers/treads, the actual riser height, and whether the design is comfortable to walk on.
How the Staircase Is Worked Out
Number of risers = Total rise ÷ Desired riser height, rounded to the nearest whole number.
Actual riser height = Total rise ÷ Number of risers. Every step comes out exactly equal, which matters more for safety than hitting your preferred height.
Number of treads = Risers − 1, because the upper floor itself forms the last step.
Total run = Treads × Tread width. This is the horizontal length the stair occupies on plan if it is built as one straight flight.
Comfort check = 2 × Actual riser + Tread. Results between 550 and 700 mm are reported as comfortable.
Worked Example
Floor-to-floor height 3,000 mm, desired riser 175 mm, tread 250 mm. 3,000 ÷ 175 = 17.1, which rounds to 17 risers. Actual riser = 3,000 ÷ 17 = 176.5 mm. Treads = 16, so the straight run is 16 × 250 = 4,000 mm or 4.00 m. Comfort check: 2 × 176.5 + 250 = 603 mm, inside the comfortable range.
Seventeen risers in one go is a long, tiring flight, so in most Indian houses this would be built as a dog-legged stair: two flights of 8 and 9 risers turning at a mid-landing. Each flight then needs only about 2 m of run, plus the landing, which fits a much smaller stair hall.
Risers for Common Floor Heights
Results with a desired riser of 175 mm and a 250 mm tread:
Floor-to-floor (mm)
Risers
Actual riser (mm)
Treads
Straight run (m)
2R + T (mm)
2,700
15
180.0
14
3.50
610
2,850
16
178.1
15
3.75
606
3,000
17
176.5
16
4.00
603
3,150
18
175.0
17
4.25
600
3,300
19
173.7
18
4.50
597
3,600
21
171.4
20
5.00
593
Total rise is measured from finished floor to finished floor. If the flooring has not been laid yet, add the thickness of the flooring and its bedding on both levels, or the first and last steps will end up a different height from the rest.
Design Guidance Used in India
The National Building Code of India (NBC 2016) sets limits for staircases. For residential buildings it is commonly applied as a riser of not more than 190 mm and a tread of at least 250 mm; for other building types the limits are stricter, with lower risers and wider treads.
The NBC limits a single flight to 15 risers, after which a landing is needed. Long flights are also harder to climb for elderly people and children.
Leave clear headroom of at least about 2.2 m above every step, measured vertically from the nosing to the underside of any beam or the flight above.
Width, handrail height and fire-escape requirements depend on the building type and on your local municipal bye-laws, so confirm them with your architect or the local authority before finalising the plan.
Common Mistakes
Using floor-to-ceiling height instead of floor-to-floor height. The slab thickness must be included.
Making the first or last step a different height to "fix" a calculation. Uneven steps are a major cause of trips, because people climb by rhythm.
Forgetting that the tread width in the formula excludes the nosing overhang. Measure the going from riser face to riser face.
Frequently Asked Questions
The number of risers must be a whole number, so the calculator rounds your desired riser height to the nearest riser count that evenly divides the total rise, then recalculates the exact riser height needed - this ensures every step in the staircase is the same height.
The top riser is typically "absorbed" into the upper floor level, so a staircase with N risers only has N-1 treads, since the top floor itself acts as the final step.
It's a widely used rule of thumb for comfortable stair proportions: twice the riser height plus the tread width should fall between roughly 550mm and 700mm, matching a natural walking stride.
10 ft is about 3,050 mm. With a target riser of 175 mm, that rounds to 17 risers of about 179 mm each, with 16 treads. Most homes split this into two flights with a landing.
For residential buildings, the National Building Code of India is commonly applied as a maximum riser of 190 mm with a minimum tread of 250 mm. Local bye-laws and other building types can be stricter, so confirm with your architect.