Steps Needed
14
14
steps needed
7.71"
10.00"
130.0"
169.0"
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Price as of Oct 12, 2026. Product prices and availability are accurate as of the date indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Inputs
Result
Steps = round(108 / 7.5) = round(14.4) = 14. Actual riser = 108 / 14 = 7.71". Total run = 10 × (14 - 1) = 130". Stringer = sqrt(108² + 130²) = sqrt(11,664 + 16,900) = sqrt(28,564) = 169.0". Angle = atan(108/130) = 39.7°.
Inputs
Result
Steps = round(36 / 7) = round(5.14) = 5. Actual riser = 36 / 5 = 7.20". Total run = 11 × (5 - 1) = 44". Stringer = sqrt(36² + 44²) = sqrt(1,296 + 1,936) = sqrt(3,232) = 56.9". Angle = atan(36/44) = 39.3°.
Inputs
Result
Steps = round(120 / 7.5) = round(16.0) = 16. Actual riser = 120 / 16 = 7.50". Total run = 11 × (16 - 1) = 165". Stringer = sqrt(120² + 165²) = sqrt(14,400 + 27,225) = sqrt(41,625) = 204.0". Angle = atan(120/165) = 36.0°.
Building codes typically require riser heights of 7-7.75 inches and tread depths of 10-11 inches. The "rule of 17" suggests rise + run should equal about 17-18 inches for comfortable stairs.
Divide total rise (floor-to-floor height) by ideal riser height (7-7.75 inches), then round. An 8-foot ceiling needs 13 steps, a 9-foot ceiling needs 14 steps, and a 10-foot ceiling needs 16 steps (with 7.5" ideal riser and 10" tread).
| Ceiling Height | Total Rise | Steps (7.5" riser) | Actual Riser | Total Run (10" tread) | Stringer Length |
|---|---|---|---|---|---|
| 8 ft | 96" | 13 steps | 7.38" | 120" | 153.7" |
| 9 ft | 108" | 14 steps | 7.71" | 130" | 169.0" |
| 10 ft | 120" | 16 steps | 7.50" | 150" | 192.1" |
| 12 ft | 144" | 19 steps | 7.58" | 180" | 230.5" |
Total rise is the vertical height from floor to floor. Total run is the horizontal distance the stairs cover. Total run = tread depth × (number of steps - 1).
Stringer length = √(total rise² + total run²). Use the Pythagorean theorem. For 108" rise and 130" run: √(108² + 130²) = √28,564 = 169" or about 14 feet.
| Total Rise | Total Run | Stringer Length | Common Lumber |
|---|---|---|---|
| 36" (deck) | 44" | 56.9" (4.7 ft) | 2×12 × 6 ft |
| 96" (8 ft ceiling) | 120" | 153.7" (12.8 ft) | 2×12 × 14 ft |
| 108" (9 ft ceiling) | 130" | 169.0" (14.1 ft) | 2×12 × 16 ft |
| 120" (10 ft ceiling) | 150" | 192.1" (16.0 ft) | 2×12 × 16 ft |
Building codes limit stair angle to approximately 42 degrees (max 7.75" riser, min 10" tread). Comfortable stairs are typically 30-37 degrees. Steeper than 42 degrees requires a ladder or ship ladder design.
Horizontal space = tread depth × (steps - 1) + landing. A typical 9-foot ceiling with 14 steps at 10" treads needs 130" (10.8 ft) of horizontal run, plus 36" for a landing at top and bottom.
| Ceiling Height | Steps | Run (10" tread) | Run (11" tread) | With Landing |
|---|---|---|---|---|
| 8 ft | 13 | 10.0 ft | 11.0 ft | 13.0-14.0 ft |
| 9 ft | 14 | 10.8 ft | 11.9 ft | 13.8-14.9 ft |
| 10 ft | 16 | 12.5 ft | 13.8 ft | 15.5-16.8 ft |
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Last Updated: Oct 12, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.
