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Road Length Cost Calculator

Work out road length cost instantly with clear inputs, formula shown and shareable results.

About Road Length Cost Calculator

Road cost is driven by area, so length times width times the rate per square metre gives the pavement cost. Drainage, kerbs, signs, markings and safety barriers are added as a percentage because they scale with length rather than area; 10-20 percent is typical for a rural carriageway.

Formulas

Pavement cost

Cost = length km x 1000 x width x rate per m²

Total

Total = pavement cost x (1 + ancillary percentage)

Worked example

With the default values below, Road Length Cost Calculator returns Total road cost of $48,300,000.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Road lengthminimum 0.01 km
5 km
Carriageway widthminimum 0.1 m
7 m
Construction rateminimum 0.01 per m²
1,200 per m²
Drainage, signs and ancillariesaccepts 0–60 %
15 %

Results

Total road cost
$48,300,000.00
Carriageway area
35,000 m²
Pavement cost
$42,000,000.00
Cost per kilometre
$9,660,000.00

Step by step

  1. 1Values used
  2. 2Pavement cost
  3. 3Total
  4. 4Total road cost= 48,300,000.00
  5. 5Carriageway area= 35,000 m²
  6. 6Pavement cost= 42,000,000.00
  7. 7Cost per kilometre= 9,660,000.00

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Road Length Cost figure worked out?

Cost = length km x 1000 x width x rate per m². Road cost is driven by area, so length times width times the rate per square metre gives the pavement cost.

Why quote cost per kilometre as well?

It is the figure decision makers compare between schemes and against benchmarks. Cost per square metre hides how wide the road is.

What values do I need to enter?

This calculator takes 4 inputs: Road length, Carriageway width, Construction rate, Drainage, signs and ancillaries. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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