| Scenario | Method | Inputs | Angle from floor | Lean from vertical |
|---|---|---|---|---|
| Partition wall leaning slightly | Rise & Run | Rise 2.40 m, Run 0.10 m | ≈ 87.61° | ≈ 2.39° |
| Short wall with visible slope | Rise & Run | Rise 2.00 m, Run 0.50 m | ≈ 75.96° | ≈ 14.04° |
| Measured length with known height | Height & Wall Length | Height 2.40 m, Length 2.50 m | ≈ 73.74° | ≈ 16.26° |
| Ramp-like grade converted to angle | Grade | Grade 10% | ≈ 5.71° | ≈ 84.29° |
| Common pitch interpretation | Pitch | Rise 6, Run 12 | ≈ 26.57° | ≈ 63.43° |
| Tall wall, small offset | Rise & Run | Rise 8 ft, Run 1 ft | ≈ 82.87° | ≈ 7.13° |
| Run and length measured | Run & Wall Length | Run 3 ft, Length 10 ft | ≈ 72.54° | ≈ 17.46° |
| Masonry wall lean check | Rise & Run | Rise 2.70 m, Run 0.15 m | ≈ 86.82° | ≈ 3.18° |
| One-in-three slope | Grade | Grade 33.333% | ≈ 18.43° | ≈ 71.57° |
| Steeper pitch example | Pitch | Rise 9, Run 12 | ≈ 36.87° | ≈ 53.13° |
Angle from floor (θ): θ = arctan(rise ÷ run). When run is zero, θ becomes 90°.
Angle from vertical (φ): φ = 90° − θ. This is commonly called wall “lean”.
Wall length (L): L = √(rise² + run²). If you provide L with rise/run, it should match.
Grade and pitch: grade(%) = 100 × (rise/run), pitch per 12 = 12 × (rise/run).
- Pick a method that matches what you measured (rise/run, length, grade, or pitch).
- Select your unit and desired decimal precision.
- Choose whether “wall angle” means from the floor or from vertical.
- Enter values, then click Calculate to view angles and slope metrics.
- Use Download CSV or Download PDF to save results.
Wall angle guide for quick, reliable measurements
1) What “wall angle” means on real sites
A wall can be described by its angle from the floor (horizontal) or by its lean from vertical. A plumb wall is 90° from the floor and 0° from vertical. Small movements are easier to interpret as lean: for example, a 2.40 m wall with a 0.10 m offset has a lean of about 2.39° from vertical, even though it reads 87.61° from the floor.
2) Rise and run: the most common field method
Measure the vertical change (rise) and the horizontal change (run) between the same two points, then the calculator uses θ = arctan(rise ÷ run). The rise/run ratio is also the slope. When rise is fixed, doubling run cuts slope in half, so your angle shifts quickly on small offsets. This is why the precision selector matters for tight tolerances.
3) Using wall length when you can’t reach the base
If you can measure the wall’s length (hypotenuse) and its height, you can still find the run using run = √(length² − height²). In a typical check, height 2.40 m and length 2.50 m produces a run near 0.70 m and an angle near 73.74° from the floor. The tool also flags length values that disagree with rise/run by more than about 2%.
4) Converting between degrees, radians, grade, and pitch
Different trades speak different languages. The calculator shows degrees for layout, radians for engineering work, grade(%) for slope specifications, and pitch for rise-per-run conventions. Grade is 100 × (rise/run). Pitch per 12 is 12 × (rise/run). A 10% grade equals about 5.71° from the floor, while a 6-in-12 pitch equals about 26.57°.
5) Unit handling and scaling for consistent results
Angles do not depend on the unit, but your rise and run must be in the same unit. This page converts mm, cm, m, inches, and feet internally so mixed measurements don’t break your workflow. If you enter grade only, the calculator can scale a sample triangle using an optional run value, which helps you visualize expected offsets at a chosen span.
6) Practical accuracy tips for straighter builds
Take rise and run from the same reference points, and avoid measuring over bulges or finishes. For tall walls, measure run at the floor and again mid-height to identify bows. If run is extremely small, tiny tape errors can change lean by tenths of a degree. Save results to CSV for job logs, or export a PDF to attach to inspection notes.
FAQs
1) Which angle should I use for a leaning wall?
If you are checking how far a wall is out of plumb, use the angle from vertical (lean). For layout from the floor, use the angle from horizontal.
2) Can I calculate an angle using only grade percentage?
Yes. Grade is rise/run expressed as a percent. Enter grade and the calculator converts it to an angle and also reports an equivalent slope ratio and pitch.
3) What does “pitch per 12” mean here?
Pitch per 12 means the rise you get for 12 units of run. A pitch of 6 per 12 equals a slope of 0.5 and an angle near 26.57° from the floor.
4) Why do I see 90° when my run is zero?
Run equals zero means the triangle is vertical. The arctan relationship approaches 90° from the floor, and the lean from vertical becomes 0°.
5) Do different units change the angle result?
No. Angles depend on the ratio rise/run, so any consistent unit works. The unit selector just converts inputs and formats the output lengths.
6) How accurate are the results for inspections?
The math is exact, but measurement quality controls accuracy. Use a stable reference, measure carefully, and select appropriate decimals. Export the PDF to keep an auditable record.