📐 Elevation Grade Calculator
Calculate elevation grade and slope
Vertical change
Horizontal distance
How to Use This Calculator
Select Calculation Type
Choose to calculate from rise and run (traditional) or from elevation change and horizontal distance. Both methods give the same result.
Enter Measurements
Input rise (vertical change) and run (horizontal distance) in feet, or elevation change and horizontal distance. Ensure run/horizontal distance is positive.
Calculate and Review
Click "Calculate Grade" to see grade percentage, slope angle, grade ratio, and slope distance. Use this for road design, drainage, and construction.
Apply Results
Use grade percentage for road design (typically 2-15%), drainage slopes (typically 1-5%), and construction planning. Verify measurements in the field.
Formula
Grade (%) = (Rise / Run) × 100
Slope Angle = arctan(Rise / Run)
Slope Distance = √(Rise² + Run²)
Example 1: Rise = 10 ft, Run = 100 ft
Step 1: Grade = (10 / 100) × 100 = 10%
Step 2: Slope Angle = arctan(10/100) = arctan(0.1) = 5.71°
Step 3: Slope Distance = √(10² + 100²) = √10,100 = 100.5 feet
Step 4: Grade Ratio = 100:10 (Run:Rise)
Example 2: Rise = 5 ft, Run = 50 ft
Step 1: Grade = (5 / 50) × 100 = 10%
Step 2: Slope Angle = arctan(5/50) = arctan(0.1) = 5.71°
About Elevation Grade Calculator
The Elevation Grade Calculator is an essential tool for surveyors, engineers, and construction professionals who need to calculate elevation grade percentage and slope from rise and run or elevation change. This calculator implements trigonometric and geometric formulas to determine grade percentage, slope angle, grade ratio, and slope distance for surveying and construction applications.
When to Use This Calculator
- Road Design: Calculate road grades and slopes for road construction
- Drainage Design: Determine drainage slopes and grades
- Surveying: Calculate grades for topographic surveys
- Construction Planning: Determine slopes for construction projects
- Educational Use: Learn and understand grade calculations
Why Use Our Calculator?
- ✅ Dual Calculation Modes: Supports rise-run and elevation-based calculations
- ✅ Accurate Formulas: Uses trigonometric and geometric equations
- ✅ Complete Analysis: Shows grade percentage, slope angle, ratio, and distance
- ✅ Easy to Use: Simple inputs for rise and run or elevation change
- ✅ Time Savings: Instant calculations eliminate manual math
Understanding Elevation Grade
Basic Principle: Elevation grade is the ratio of vertical change (rise) to horizontal distance (run), expressed as a percentage. Grade = (Rise / Run) × 100%. Grade indicates slope steepness: higher grade means steeper slope. Grade is used in road design, drainage, and construction.
Common Grades: Road grades: 2-6% for highways, 6-10% for local roads, up to 15% for steep roads. Drainage grades: 1-5% for surface drainage, 0.5-2% for pipe drainage. Building grades: 2-5% away from buildings for drainage.
Slope Angle: Slope angle is calculated as Angle = arctan(Rise / Run). Grade percentage and slope angle are related: Grade % = tan(angle) × 100. For small angles, grade % ≈ angle (in degrees) × 1.75 (approximation).
Tips for Best Results
- Accurate Measurements: Measure rise and run accurately for precise grade calculation
- Consistent Units: Use consistent units (feet, meters) for all measurements
- Verify in Field: Verify calculated grades with actual field measurements
- Consider Terrain: Account for terrain variations in measurements
- Check Standards: Verify grades meet applicable standards and codes
Frequently Asked Questions
How do I calculate elevation grade?
Grade (%) = (Rise / Run) × 100. For example, Rise = 10 ft, Run = 100 ft: Grade = (10/100) × 100 = 10%. The calculator does this automatically from rise and run or from elevation change and horizontal distance.
What is a typical road grade?
Typical road grades: 2-6% for highways (gentle), 6-10% for local roads (moderate), up to 15% for steep roads. Maximum grades vary by road type, terrain, and regulations. Steeper grades require longer stopping distances and slower speeds.
What is the difference between grade and slope angle?
Grade is expressed as a percentage (Rise/Run × 100), while slope angle is expressed in degrees (arctan(Rise/Run)). For example, 10% grade = 5.71° slope angle. Grade is more commonly used in construction, while angle is used in trigonometry and engineering.
How do I convert grade percentage to slope angle?
Slope Angle = arctan(Grade / 100). For example, 10% grade: Angle = arctan(0.1) = 5.71°. For small angles, approximation: Angle (degrees) ≈ Grade % / 1.75. The calculator shows both grade percentage and slope angle automatically.
What is a typical drainage grade?
Typical drainage grades: 1-5% for surface drainage (away from buildings), 0.5-2% for pipe drainage (minimum for flow), 2-5% for building perimeter drainage. Minimum grades ensure proper water flow and prevent standing water. The calculator helps determine appropriate drainage grades.