Free · Driveway calculators 🚧

Road Base Ordering Allowance Calculator

Estimate base-course volume, mass and cost with a chosen additional-material percentage.

  • Formula & worked example
  • Private in your browser
  • No signup
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 10 × 2 meter base layer at 10 centimeters deep contains 2 m³. With density 1,600 kg/m³ and 20% added material, order mass is 3.84 metric tonnes. At 100 per tonne, that costs 384.

Geometric volume = area × depth; order mass = volume × density × (1 + added fraction)

Worked example

Enter these known values and leave the other values blank.

Road length
10 m
Road width
2 m
Road depth
10 cm
Gravel density
1600 kg/m³
Additional material allowance
20 %
Price per ton
100 USD / t
Road area
20 m²
Road base volume
2 m³
Estimated amount of gravel
3.2 t
Mass including allowance
3.84 t
Price per volume
160 USD / m³
Total cost
384 USD

Assumptions and limitations

  • No. This model multiplies by 1.20 for a 20% addition. Compensating for a true 20% loss would require division by 0.80. Enter the appropriate added-material percentage for your project.
  • Use consistent units and project-specific dimensions, density and prices. This geometric estimate does not add quantities that are absent from the formula.

Common questions

Is a 20% allowance the same as 20% volume loss during compaction?

No. This model multiplies by 1.20 for a 20% addition. Compensating for a true 20% loss would require division by 0.80. Enter the appropriate added-material percentage for your project.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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