Gradient & Slope Calculator
Difference in Level
0.00 m
Gradient (Ratio)
1 in --
Slope Percentage
0.00 %
Angle (Degrees)
0.00°
How to Calculate Gradient in Surveying
In civil engineering, specifically for roads, railways, and drainage pipes, we need to maintain a specific slope. This is often calculated using an Auto Level or Total Station.
(Shows a triangle with Rise, Run, and Slope Angle)
Key Formulas
1. Difference in Level (Rise/Fall):
$$ \Delta H = \text{RL}_A - \text{RL}_B $$
2. Gradient (1 in N):
$$ N = \frac{\text{Distance}}{\Delta H} $$
(Expressed as 1 in 50, 1 in 100, etc.)
3. Slope Percentage (%):
$$ \% = \left( \frac{\Delta H}{\text{Distance}} \right) \times 100 $$
Standard Gradients used in Construction
| Application | Typical Gradient | Percentage |
|---|---|---|
| Drainage Pipe (Small) | 1 in 60 | ~1.67% |
| Road Camber | 1 in 50 | 2.0% |
| Wheelchair Ramp | 1 in 12 (Max) | 8.3% |
| Railway Track | 1 in 100 to 1 in 400 | 0.25% - 1.0% |
Solved Example
Problem: A drainage pipe needs to be laid between two manholes 50m apart. The RL of the first manhole is 100.500m and the second is 99.500m. Find the gradient.
1. Find Difference (Rise):
\(100.500 - 99.500 = 1.000 \text{ m}\)
2. Calculate Gradient (1 in N):
\(N = 50 / 1.0 = 50\)
Result: 1 in 50
1. Find Difference (Rise):
\(100.500 - 99.500 = 1.000 \text{ m}\)
2. Calculate Gradient (1 in N):
\(N = 50 / 1.0 = 50\)
Result: 1 in 50