楼梯计算器
This stair calculator determines the number of steps, actual riser height, total run, stringer length, and stair angle from your floor-to-floor rise. Enter the total rise in feet and inches (or total inches), along with your desired riser height and tread depth, to get a complete stair layout with automatic IRC building code compliance checking.
Stair Calculator
Calculate step count, riser height, total run, and building code compliance
Total Rise
IRC: 4"–7.75" (default 7.5")
IRC: min 10" (default 10")
Frequently Asked Questions
楼梯计算器是如何工作的？
楼梯计算器根据总高度（楼层层高）计算楼梯的踏步数、每步高度（立面高度，Riser）和踏步深度（踏面宽度，Tread）。标准关系：2×立面高度 + 踏面宽度 ≈ 60-65 cm（舒适步行公式）。
楼梯的舒适坡度是多少？
舒适楼梯的参数：立面高度（Riser）15-20 cm（理想 17 cm）；踏面宽度（Tread）25-30 cm（理想 27-28 cm）；坡角通常在 30-35°之间。建筑规范要求住宅楼梯最大坡角不超过 42°，最大立面高度 ≤ 22 cm。
如何计算楼梯所需材料？
材料计算：踏板数量 = 踏步数（立面板数量 = 踏步数 + 1 或 - 1，取决于设计）；楼梯梯梁长度 = √(水平投影长度² + 楼梯总高度²)；扶手长度 = 梯梁长度 + 延伸段。本计算器提供完整材料清单。
建筑规范对楼梯有什么要求？
不同国家/地区的建筑规范略有不同，但通常要求：最大立面高度（Riser）≤ 22 cm，最小踏面宽度（Tread）≥ 22 cm，扶手高度 90-110 cm，最小净宽 ≥ 91 cm（住宅）或 ≥ 120 cm（公共建筑）。设计前请查阅当地建筑规范。
How to Use the Stair Calculator
The Stair Calculator helps contractors, builders, and DIYers design code-compliant staircases. Enter the total rise (floor-to-floor height) and desired riser height to instantly get the exact number of steps, actual riser height, total run, stringer length, and stair angle — with automatic IRC building code compliance checking.
Stair Calculator Guide Contents
1. Stair Formulas
Key Principle: Because the total rise must be divided evenly among all risers, rounding the step count causes the actual riser height to differ slightly from your desired riser height. Always verify the actual riser (Total Rise ÷ Number of Steps) against code limits.
Number of Steps = ROUND(Total Rise ÷ Desired Riser Height)
Actual Riser = Total Rise ÷ Number of Steps
Total Run = (Number of Steps − 1) × Tread Depth
Stringer = √(Total Rise² + Total Run²)
Angle = arctan(Actual Riser ÷ Tread Depth) × (180 ÷ π)
Note that the total run uses (steps − 1)treads because the top landing does not require a tread — the floor itself serves as the last "step."
2. IRC Building Code Requirements
The International Residential Code (IRC Section R311.7) establishes minimum stair dimensions for residential construction. Local jurisdictions may be more restrictive; always verify with your local building department.
| Dimension | IRC Minimum | IRC Maximum | Notes |
|---|---|---|---|
| Riser Height | 4" | 7¾" (7.75") | Variation ≤ ⅜" across all risers |
| Tread Depth | 10" | No maximum | Variation ≤ ⅜" across all treads |
| Stair Width | 36" | No maximum | Clear width above handrail |
| Headroom | 6'8" (80") | No maximum | Measured vertically from tread nose |
Important: This calculator checks riser height and tread depth only. Stair width, headroom, handrail requirements, and landing dimensions are not calculated here. Always consult your local building department for permit requirements.
3. The Comfort Rule
Even when stairs meet code, they may feel awkward to climb. Two classic rules of thumb help you design stairs that feel natural for an average stride:
2R + T = 24–25" Rule
Two risers plus one tread should equal 24 to 25 inches. For a 7" riser and 11" tread: 2 × 7 + 11 = 25. This formula balances the forward motion of a stride against the vertical lift required.
R + T = 17–18" Rule
One riser plus one tread should equal 17 to 18 inches. For a 7.5" riser and 10.5" tread: 7.5 + 10.5 = 18. This is a simpler check for reasonable stair geometry.
Pro Tip:A 7" riser with a 11" tread (2×7 + 11 = 25) is considered the gold standard for comfortable residential stairs and satisfies both comfort rules while staying well within IRC limits.
4. Common Stair Dimensions
| Application | Riser Height | Tread Depth | Angle |
|---|---|---|---|
| Comfortable residential | 7" | 11" | 32.5° |
| Standard residential (IRC default) | 7.5" | 10" | 36.9° |
| Steeper / space-saving | 7.75" | 10" | 37.8° |
| Exterior / landscape steps | 6" | 12"–14" | 23°–27° |
| Basement / utility stair | 7.75" | 10" | 37.8° |
Stair Angle Reference
- 20°–30° — Gentle, easy to climb; requires more horizontal space
- 30°–40° — Comfortable residential range; most common
- 40°–45° — Steep; acceptable for utility stairs, tiring for daily use
- Above 45° — Very steep; approaches ladder territory