Pente de toiture : angle, pourcentage et dénivelé

Calculez angle, pente en pourcentage, pente de toiture (x sur 12), longueur inclinée et coefficient de chevron à partir du dénivelé et de la distance horizontale.

Mis à jour Exemples vérifiés : 8

Negative for a downhill slope
Essayer
Angle
°
Angle: 26.5651 °
Décimales maximales : 4 ; Au plus proche, égalités en s’éloignant de zéro
Note scolaire
50%
Roof pitch
6in 12
Ratio (rise : run)
1 : 2
Rise per unit of run
0.5
Rafter length factor
1.118034
Slope length
13.4164cm

This slope rises 0.5 for every 1 of run: 26.57° from horizontal, a 50 % grade, or a 6/12 roof pitch. Its sloped length is 13.4164 cm.

Slope profile, to scale

run 12 cmrise 6 cm26.57°6/12 pitch · 50 %
Comment le calcul est effectué S
  1. Slope

    m=riserun=612=0.5m = \frac{\text{rise}}{\text{run}} = \frac{6}{12} = 0.5
  2. Angle

    θ=arctan⁡m=arctan⁡0.5=26.565051∘\theta = \arctan m = \arctan 0.5 = 26.565051^\circ
  3. Grade and pitch

    grade=100m=50 %,pitch=12m=6 in 12\text{grade} = 100m = 50\,\%,\qquad \text{pitch} = 12m = 6 \text{ in } 12
  4. Rafter factor

    1+m2=1+0.52=1.118034\sqrt{1 + m^2} = \sqrt{1 + 0.5^2} = 1.118034

    Multiply a horizontal run by this to get the sloped length.

  5. Slope length

    rise2+run2=12×1.118034=13.416408 cm\sqrt{\text{rise}^2 + \text{run}^2} = 12 \times 1.118034 = 13.416408\,\text{cm}

À propos de Pente de toiture : angle, pourcentage et dénivelé

Every way of stating a slope comes from one ratio, m = rise ÷ run. The angle from horizontal is arctan m, the percent grade is 100m, the roof pitch is 12m (units of rise per 12 of run), and the rafter factor √(1 + m²) turns a horizontal run into the sloped length. Enter a rise and run, or any one of the other forms, and the rest follow.

The default rise of 6 over a run of 12 is a 6/12 roof: 26.57°, a 50% grade and a rafter factor of 1.1180, so 12 cm of run needs 13.4164 cm of rafter. Ramps and roads use the same numbers: the steepest ramp the 2010 ADA Standards allow, 1:12, is an 8.33% grade, or 4.76°.

Percent grade is not an angle: a 100% grade is 45°, and a vertical face has no finite grade or pitch, so angles must lie between −90° and 90°. A negative rise describes a downhill slope.

Exemples détaillés

Rise 6, run 12 (a 6/12 roof)

Mesure connue
Rise and run
Rise
6 cm
Run (horizontal distance)
12 cm
Unité des résultats
Centimètres (cm)
Angle
26.565051 °
Note scolaire
50%
Roof pitch
6 in 12
Ratio (rise : run)
1 : 2
Rafter length factor
1.118034
Slope length
13.416408 cm

Source de vérification : Python 3.8 math: degrees(atan(0.5)), sqrt(1.25), sqrt(6**2 + 12**2)

45°

Mesure connue
Angle
Angle from horizontal
45 °
Note scolaire
100%
Roof pitch
12 in 12
Ratio (rise : run)
1 : 1
Rafter length factor
1.414214

Source de vérification : tan 45° = 1; Python 3.8 math.sqrt(2)

8 % road grade

Mesure connue
Percent grade
Note scolaire
8%
Angle
4.573921 °
Roof pitch
0.96 in 12
Ratio (rise : run)
1 : 12.5

Source de vérification : Python 3.8 math: degrees(atan(0.08)); 12 × 0.08; 1/0.08

4/12 roof pitch

Mesure connue
Roof pitch
Pitch
4 in 12
Angle
18.434949 °
Note scolaire
33.333333%
Rafter length factor
1.054093

Source de vérification : Python 3.8 math: degrees(atan(4/12)), sqrt(1 + 1/9)

Questions

How do you convert percent grade to degrees?

Take the arctangent of the grade divided by 100: θ = arctan(grade/100). An 8% road grade is arctan 0.08 = 4.57°, and a 100% grade is 45°, not 90°. The reverse is grade = 100 × tan θ, so a 30° slope is a 57.7% grade.

What angle is a 6/12 roof pitch?

26.57°. A pitch of x/12 means x units of rise for every 12 of run, so the angle is arctan(x/12): 4/12 is 18.43°, 6/12 is 26.57°, 8/12 is 33.69° and 12/12 is 45°. The rafter factor for 6/12 is √1.25 = 1.118, so 12 ft of horizontal run needs 13.42 ft of rafter before any overhang.

What is the maximum slope for a wheelchair ramp?

1:12 under the 2010 ADA Standards for Accessible Design (§405.2): one unit of rise for every 12 of run, an 8.33% grade or 4.76°. Each ramp run may rise at most 30 in (§405.6), so a 30 in rise needs a run of at least 30 ft. Other countries set their own limits in their building codes.

How do you calculate rise over run?

Divide the vertical rise by the horizontal run, both in the same unit: m = rise/run. A roof that rises 6 in over 12 in of run has m = 0.5. Measure the run horizontally, not along the surface: the sloped length here is 13.42 in, and dividing by it gives 0.447, the sine of the angle rather than the slope.

Quelle est la précision de « Pente de toiture : angle, pourcentage et dénivelé » ?

La précision dépend de vos données et des hypothèses de la méthode. Le calcul décimal utilise 50 chiffres significatifs, mais les estimations, méthodes numériques et données sources peuvent être moins précises ; l’arrondi affiché ne supprime pas ces limites. Exemples résolus vérifiés à partir de sources indépendantes : 8. Par exemple, « Rise 6, run 12 (a 6/12 roof) » est vérifié à l’aide de Python 3.8 math: degrees(atan(0.5)), sqrt(1.25), sqrt(6**2 + 12**2).

D’où vient cette méthode ?

OpenStax College Algebra 2e, §4.1 — slope as rise over run; US Access Board, ADA Standards §405.2 — ramp slope 1:12 (8.33 %).

À propos de ce calculateur

m=riserun,θ=arctan⁡m,grade=100m %pitch=12m in 12,factor=1+m2\begin{gathered} m = \frac{\text{rise}}{\text{run}},\quad \theta = \arctan m,\quad \text{grade} = 100m\,\% \\[6pt] \text{pitch} = 12m \text{ in } 12,\quad \text{factor} = \sqrt{1 + m^2} \end{gathered}

Sources

  1. OpenStax College Algebra 2e, §4.1 — slope as rise over run
  2. US Access Board, ADA Standards §405.2 — ramp slope 1:12 (8.33 %)

Vérifié avec les références

Ce calculateur comprend 8 exemples résolus dont les réponses proviennent de sources indépendantes. Ils font partie de la suite de tests et peuvent aussi être exécutés ici.

Calculatrices associées