Site Engineer Tools
  1. Home
  2. Calculators
  3. Level Interpolation Schedule

Free site calculator

Level Interpolation and Chainage Schedule

Generate intermediate levels at a chosen chainage interval between known start and end levels, then export the schedule as CSV.

Level Interpolation and Chainage Schedule

Enter your data

Use consistent units and verify the point or flow direction.

No sign-in
m
m
m
m
m
CSV template
Inputs are processed in this browser. This calculator does not send project data to a server.
Check before use: This is an independent calculation aid, not approved design information. Confirm inputs, units, coordinate order, tolerances and project conventions before construction or setting out.

Linear interpolation

The calculator assumes one constant straight gradient between the two known points. Each intermediate level is calculated in direct proportion to its distance from the start chainage.

level at x = start level + (end level − start level) × (x − start chainage) ÷ total length

Exact end point

If the chosen interval does not divide the total length exactly, the schedule still includes a final row at the precise end chainage rather than overshooting or omitting it.

Suitable uses

The schedule is useful for formation levels, kerb lines, drainage inverts and simple grading checks where a single constant gradient is intended. It is not a vertical-curve calculator.

Frequently asked questions

Can the end level be higher than the start level?

Yes. The schedule will show a rising gradient and interpolate levels accordingly.

Does this support vertical curves?

No. It assumes a straight grade between the endpoints. Parabolic vertical curves require curve length and grade data.

Why is the final interval shorter?

The calculator always includes the exact end chainage. When the total length is not an exact multiple of the interval, the final segment is shorter.