Step-Ratio Formula — Geometric specification
Category: Geometric specification
Rule of thumb for comfortable stairs: 2 × rise + going ≈ 63 cm.
The step-ratio formula is the most important comfort rule in stair construction. It describes the optimum relationship between rise (R) and going (G): two rises plus one going should equal approximately 63 cm (2R + G ≈ 630 mm, tolerance ±30 mm). This dimension corresponds to the average stride length of an adult and ensures a harmonious, rhythmic ascent. A rise-to-going ratio of 17/29 cm is considered particularly comfortable.
Related terms
Related terms: Rise-to-Going Ratio, Comfort Rule, Stair Formula, Step Length, Sinus Stair Formula, Pitch Angle.