Rise Over Run Calculator

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Rise Over Run Calculator

Results:

Slope (m):

Slope Fraction:

Grade Percentage: %

Angle (Degrees): °

function calculateSlope() { var rise = parseFloat(document.getElementById('riseInput').value); var run = parseFloat(document.getElementById('runInput').value); var resultDiv = document.getElementById('slopeResult'); if (isNaN(rise) || isNaN(run)) { alert("Please enter valid numbers for both rise and run."); return; } if (run === 0) { alert("Run cannot be zero (Vertical slope is undefined)."); return; } var slope = rise / run; var grade = slope * 100; var angleRad = Math.atan(slope); var angleDeg = angleRad * (180 / Math.PI); // Simplify fraction for display (basic logic) function getGCD(a, b) { return b ? getGCD(b, a % b) : a; } var common = Math.abs(getGCD(rise, run)); var fractionText = (rise / common) + " : " + (run / common); document.getElementById('decimalResult').innerText = slope.toFixed(4); document.getElementById('fractionResult').innerText = fractionText; document.getElementById('gradeResult').innerText = grade.toFixed(2); document.getElementById('angleResult').innerText = angleDeg.toFixed(2); resultDiv.style.display = 'block'; }

Understanding Slope: How to Use the Rise Over Run Calculator

In mathematics, engineering, and construction, understanding the relationship between vertical change and horizontal change is essential. This relationship is commonly referred to as "Rise over Run." Whether you are building a staircase, installing a wheelchair ramp, or calculating the pitch of a roof, our Rise Over Run Calculator provides instant precision for your projects.

What is Rise Over Run?

Slope is the measure of the steepness of a line. In a coordinate plane, it represents the change in the vertical "y" axis (Rise) divided by the change in the horizontal "x" axis (Run).

  • Rise: The vertical distance between two points (how much it goes up or down).
  • Run: The horizontal distance between two points (how far it goes left or right).

The Slope Formula

The mathematical formula for calculating slope (m) is:

m = Rise / Run

To find the Grade Percentage, you multiply the slope by 100. To find the Angle in degrees, you use the inverse tangent (arctan) of the slope.

Practical Examples

1. Staircase Construction

If you are building stairs and the total vertical height from the first floor to the second floor is 10 feet (Rise) and the horizontal length available for the stairs is 15 feet (Run), your slope is 10/15 or 0.66. This results in a 66.6% grade.

2. Roof Pitch

Roofers often describe pitch as "4 in 12." This means for every 12 inches of horizontal run, the roof rises 4 inches. Using the calculator, a Rise of 4 and a Run of 12 gives a slope of 0.333 and an angle of approximately 18.43 degrees.

3. ADA Ramp Requirements

The Americans with Disabilities Act (ADA) requires a maximum slope of 1:12 for ramps. This means for every 1 inch of rise, you must have 12 inches of run. Entering 1 for Rise and 12 for Run in our calculator will show a slope of 0.0833 (8.33% grade).

Frequently Asked Questions

Can the rise be negative?
Yes. A negative rise indicates that the line is going downward from left to right (a descent), while a positive rise indicates an upward incline.

What happens if the run is zero?
If the run is zero, the slope is considered "Undefined." This represents a perfectly vertical line, which does not have a measurable slope in standard Euclidean geometry.

Is grade percentage the same as the angle?
No. While they both measure steepness, the grade percentage is a linear ratio (Rise/Run * 100), whereas the angle is measured in degrees using trigonometry. A 100% grade is a 45-degree angle.

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