Staircase Calculator
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Enter the floor-to-floor height, your tread and a target riser, and get the number of steps, the actual riser, the comfort check and the concrete volume for a straight RCC flight.
Staircase Calculator
Steps, riser/tread comfort and waist-slab concrete for a straight flight
Straight flight
H = floor height · R = riser · T = tread
Slab thickness under the steps
Steps in the flight
20 risers
19 treads · actual riser 150 mm
Risers
20
Treads
19
Actual riser
150 mm
Concrete
1.20 m³
Flight geometry & concrete
Risers
20
Treads
19
Actual riser
150 mm
2R + T
550 mm
Total going
4,750 mm
Waist slab
0.84 m³
Steps
0.36 m³
Total concrete
1.20 m³
Cost estimate — edit to your local rates
| Material | Quantity | Rate (₹) | Amount |
|---|---|---|---|
| Concrete (in place) | 1.20 m³ | /m³ | ₹7,793 |
| Total (materials) | ₹7,793 | ||
Indicative — type today's local rates. Labour is separate: see the material price lists and labour rates.
Comfort rule 2R + T = 550 mm — within the comfortable 550–650 mm range. Keep risers ≤ 190 mm and treads ≥ 250 mm for a home. Take the concrete volume to the concrete calculator for cement, sand and aggregate.
How it works
- Number of risers = floor height ÷ target riser, rounded to a whole number.
- Actual riser = floor height ÷ number of risers — the height is shared equally, so it rarely lands exactly on your target.
- Treads = risers − 1 (the top riser lands on the finished floor).
- Comfort check 2R + T — a comfortable stair keeps twice the riser plus the tread between about 550 and 650 mm. Keep risers ≤ 190 mm and treads ≥ 250 mm in a home.
- Concrete = the sloped waist slab (width × thickness × sloped length) plus the triangular steps on top.
Worked example
A 3,000 mm floor height, 250 mm tread, 150 mm target riser, 1 m wide, 150 mm waist slab:
- Risers = 3000 ÷ 150 = 20 risers (19 treads), actual riser 150 mm
- Comfort 2R + T = 2 × 150 + 250 = 550 mm — within range
- Concrete (waist slab + steps) ≈ 1.20 m³
Comfort guide
| Value | Home range |
|---|---|
| Riser (R) | 150–190 mm |
| Tread / going (T) | 250–300 mm |
| 2R + T | 550–650 mm |
| Width | ≥ 900 mm (1 m typical) |
Frequently asked questions
How many steps for a floor height of 3 metres? At a 150 mm riser, 3,000 ÷ 150 = 20 risers, so 19 treads plus the landing. A larger target riser gives fewer, steeper steps.
What is the 2R + T rule? Twice the riser plus the tread should be about 550–650 mm for a comfortable walking rhythm. It links riser and tread so the stair is neither too steep nor too shallow.
What is a comfortable riser and tread? For homes, a riser of 150–175 mm with a tread of 250–300 mm is comfortable. Steeper risers save space but are tiring and less safe.
How much concrete does a staircase need? It is the waist slab (the sloped slab under the steps) plus the triangular steps. A typical 3 m flight 1 m wide with a 150 mm waist is around 1.2 m³ — take that to the concrete calculator for materials.
Related
CivilSite Editorial Team✓ Engineer reviewed
Written and reviewed by practising civil engineers with 10+ years of Indian residential construction experience.