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Landscaping & base layers

Gravel Calculator

Estimate gravel for driveways, paths, and base layers in cubic yards, weight, tons, and bags without hiding the density assumption.

  • Metric & imperial
  • Adjustable bulk density
  • Visible project allowance

Coverage & material

Enter the gravel layer

Measurement system

This device

Saved estimates

Save an estimate to keep it here. Data stays in this browser.

Transparent by design

Gravel volume and weight formula

A rectangular gravel layer is a rectangular prism. BuildMeasure keeps geometry separate from the material-density assumption so you can inspect exactly where volume ends and estimated weight begins.

Net volumeV = length × width × depthOrder volumeVorder = V × (1 + allowance ÷ 100)Estimated massM = Vorder × bulk densityComplete bagsBags = ceil(M ÷ bag weight)

The default `93 lb/ft³` value is only a dry planning example from USACE HEC-HMS documentation. Replace it with the loose or compacted bulk density for the actual aggregate whenever that value is available.

Worked example

A 10 ft × 10 ft gravel layer

Use a 4 in installed depth, 10% project allowance, 93 lb/ft³ planning density, and 50 lb bags. Density remains an adjustable material assumption.

  1. 01
    Find net volume10 × 10 × (4 ÷ 12) = 33.333 ft³
  2. 02
    Add 10% allowance33.333 × 1.10 = 36.667 ft³ = 1.358 yd³
  3. 03
    Estimate mass36.667 × 93 = 3,410 lb
  4. 04
    Round complete bagsceil(3,410 ÷ 50) = 69 bags
Verified result1.358 yd³; 3,410 lb; 69 × 50 lb bags

Changing density changes mass and bags, not geometric volume. Confirm loose or compacted density with the supplier.

Common questions

Gravel calculator FAQ

Volume is geometric; tonnage depends on the material.

How does the gravel calculator find volume?

It converts length, width, and placed depth to a consistent unit, multiplies them to find the rectangular layer volume, then applies the project allowance you selected.

Why can I change gravel density?

Gravel bulk density changes with stone type, grading, moisture, voids, and whether the material is loose or compacted. A fixed universal density would create false precision, so BuildMeasure exposes the value and lets you replace the planning example with supplier or test data.

Should I use loose or compacted bulk density?

Use a density that matches the volume state you are estimating. ASTM C29/C29M distinguishes loose and compacted aggregate bulk density. Ask the supplier which condition their value represents and whether delivered volume already accounts for compaction.

What should the project allowance include?

Use it only for project-specific needs such as installation loss, an uneven base, or a known compaction allowance. The calculator does not hide or automatically choose a compaction factor.

Are the tonnage and bag results exact?

The geometry follows the entered measurements, but mass depends on the selected bulk density. Bag count also depends on the exact packaged weight. Confirm both values and supplier delivery increments before purchasing.

Can I use metric measurements?

Yes. Metric mode uses meters for length and width, centimeters for depth, kilograms per cubic meter for density, and kilograms for bag weight. Switching systems converts the values already entered.

Continue planning

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