Long Section Table Builder
A free, browser-based tool. Runs entirely in your browser — no sign up, nothing stored.
Chainage & reduced level
| Chainage (m) | Reduced level (m) | |
|---|---|---|
List the profile points in order with increasing chainage. Runs in your browser.
Segment grades
| Segment | Length | Rise / fall | Grade | 1 : N |
|---|---|---|---|---|
| 0.000–20.000 | 20.000 | +0.400 | 2.000% | 1:50.0 |
| 20.000–50.000 | 30.000 | -0.400 | -1.333% | 1:75.0 |
Grade = (RL change ÷ chainage change) × 100. A positive grade rises with chainage; a negative grade falls.
How to use this calculator
- Enter each profile point's chainage and reduced level, in order with increasing chainage.
- Add or remove points to match your long section.
- Read the grade of each segment as a percentage and as 1 in N, with the total length and rise/fall.
How it works
Between each pair of points the grade is the change in reduced level over the change in chainage: grade = (RL₂ − RL₁) ÷ (chainage₂ − chainage₁), shown as a percentage and a 1 in N ratio.
A positive grade rises with chainage; a negative grade falls. The totals are the overall length and the net rise or fall along the section.
Worked example
RL 100.0 at 0, 100.4 at 20, 100.0 at 50. The first segment rises 0.4 m over 20 m = 2% (1:50); the second falls 0.4 m over 30 m = −1.333% — so the section returns to its start level.
Frequently asked questions
What's the difference between a long section and a cross section?
A long section runs along the centreline (chainage vs level); a cross section runs across it at one chainage (offset vs level). This tool builds the long section grades.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.