Calculate Slope

Online calculator for calculating slopes from rise and horizontal distance

Slope Calculator

Slope from Rise and Run

Calculates the slope of a line from the vertical rise and the horizontal run as angle and percentage.

Height difference (vertical)
Horizontal distance
Results
Slope angle:
Slope percentage:

Visualization

Calculate slope

The graphic shows the slope triangle with rise (vertical) and run (horizontal).
The slope is the ratio of rise to horizontal distance.

What is a Slope?

The slope describes how steeply a line or surface rises:

  • Ratio: Rise divided by horizontal distance
  • Units: Percent (%) or angle (°)
  • Application: Roads, roofs, ramps
  • Positive values: Rise upward
  • Negative values: Decline downward
  • Zero: Horizontal surface

Slope in Percent

The percentage is the most common form of slope specification:

Formula
\[\text{Slope} = \frac{\text{Rise}}{\text{Run}} \times 100\%\]

Ratio multiplied by 100

Examples
  • 10%: 10 m rise over 100 m
  • 5%: Typical road gradient
  • 100%: 45° angle

Slope Angle

The slope angle is the geometric representation of the slope:

Angle Formula
\[\alpha = \arctan\left(\frac{\text{Rise}}{\text{Run}}\right)\]

Arctangent of the ratio

Angle Ranges
  • 0°: Horizontal
  • 45°: 100% slope
  • 90°: Vertical

Formulas for Slope Calculation

Basic Formula - Slope as Ratio
\[\text{Slope} = \frac{\text{Rise}}{\text{Run}}\]

Ratio of vertical rise to horizontal distance

Slope in Percent
\[\text{Percent} = \frac{\text{Rise}}{\text{Run}} \times 100\%\]

Slope as percentage

Slope Angle
\[\alpha = \arctan\left(\frac{\text{Rise}}{\text{Run}}\right)\]

Slope as angle in degrees

Convert Percent to Angle
\[\alpha = \arctan\left(\frac{\text{Percent}}{100}\right)\]

From percent to degrees

Convert Angle to Percent
\[\text{Percent} = \tan(\alpha) \times 100\%\]

From degrees to percent

Example

Example Calculation
Rise: 15 Run: 200
Slope in Percent
\[\frac{15}{200} \times 100\% = 7.5\%\]

The slope is 7.5%

Slope Angle
\[\alpha = \arctan\left(\frac{15}{200}\right) \approx 4.29°\]

The slope angle is approximately 4.29°

Interpretation
  • 7.5%: Moderate slope
  • 4.29°: Gentle rise
  • Assessment: Suitable for roads and paths
Practical Values
  • 2-4%: Sidewalk
  • 5-8%: Normal road
  • 10-15%: Steep road

Understanding Slope in Practice

The slope is a fundamental concept in engineering, construction, and geography. It describes how steeply a surface, road, or line is inclined relative to the horizontal. The calculation is done via the ratio of vertical rise to horizontal distance.

Definition and Calculation

The slope is given as a dimensionless number or as a percentage:

\[\text{Slope} = \frac{\text{Rise}}{\text{Run}}\]

Here, the rise is the vertical height difference and the run is the horizontal distance between two points.

Forms of Representation

Percentage

The most common form in construction and road building. 100% corresponds to a 45° angle.

Decimal Number

In mathematics often represented as a decimal fraction (e.g., 0.075 for 7.5%).

Angle Specification

In degrees (°) for geometric calculations and technical drawings.

Ratio

As a fraction (e.g., 1:8) particularly common in architecture.

Practical Applications

Slope calculations are found in many areas of daily life:

  • Road construction: Planning road gradients, highway ramps
  • Architecture: Roof slopes, stair gradients, accessibility ramps
  • Landscaping: Garden design, drainage, terracing
  • Mechanical engineering: Conveyor systems, slides, conveyor belts
  • Surveying: Terrain surveying, contour lines on maps
  • Sports: Ski slopes, cycling routes, running tracks

Typical Slope Values

Sidewalks

2-4% (1.1-2.3°)
Comfortable slope

Normal Roads

5-8% (2.9-4.6°)
Typical traffic roads

Steep Roads

10-15% (5.7-8.5°)
Mountain roads, warning signs

Safety Aspects

When planning slopes, various safety aspects must be considered:

  • Vehicles: Braking distance and acceleration capability
  • Pedestrians: Comfort and slip hazard
  • Wheelchair users: Maximum 6% for independent use
  • Drainage: Minimum gradient of 0.5% for water runoff

Mathematical Relationship

Slope calculation is based on trigonometry. The tangent of the slope angle corresponds to the slope as a decimal number. This enables conversion between percentage, angle, and ratio specifications.

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More graphics functions

Angle of two lines  •  Angle of two vectors  •  Center of a straight line  •  Distance of two points  •  Distance of a point and a line  •  Rise over Run  •  Slope of a line  •  Straight line equation  •  Circular arc  •  Helix  •  Koch snowflake  •