What is Blondel's rule for staircases?

Blondel's rule states 2R + T = 600–650 mm, where R is riser height and T is tread depth. This ensures comfortable stair proportions for average human stride.

What is the standard riser height for Indian buildings?

Per NBC (National Building Code of India), risers should be 150–200 mm. Residential stairs typically use 175 mm risers for comfort.

What is the minimum tread depth?

Per NBC, treads should be minimum 250 mm. Commercial and public buildings typically use 280–300 mm treads for safety and comfort.

Staircase Calculator

Calculate staircase risers, tread depth, and stringer length.

Floor-to-floor height (m)

Available horizontal length (m)

Desired riser height (mm)

Min tread depth (mm)

Stair width (mm)

Number of risers

Actual riser height

166.7 mm

Tread depth

296.7 mm

Number of treads

Total going

5.04 m

Stringer length

5.87 m

Fits in space

✗ No

Concrete (waist)

0.534 m³

NBC / IS 456 Compliance Checks

Riser 150–200 mm✓ Pass — 166.7 mm

Tread ≥ 250 mm✓ Pass — 296.7 mm

Blondel 590–650 mm (2R+T)✓ Pass — 630.0 mm

Fits in available space✗ Fail — 5.04 m of 4 m available

Design staircases to code standards

Enter floor height and available space to calculate number of steps, riser height, tread depth, and stringer length. NBC compliance is verified automatically.

Frequently asked questions

What is Blondel's rule for staircases?: Blondel's rule states 2R + T = 600–650 mm, where R is riser height and T is tread depth. This ensures comfortable stair proportions for average human stride.
What is the standard riser height for Indian buildings?: Per NBC (National Building Code of India), risers should be 150–200 mm. Residential stairs typically use 175 mm risers for comfort.
What is the minimum tread depth?: Per NBC, treads should be minimum 250 mm. Commercial and public buildings typically use 280–300 mm treads for safety and comfort.

Design staircases to code standards

Frequently asked questions

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