Gravel Calculator
Estimate how much gravel you need for a rectangular project using length, width, depth and waste allowance. The calculator also estimates material weight and optional cost using a bulk-density value.
Best for: driveways, paths, patios, drainage areas, landscaping beds and other rectangular gravel projects.
Estimate Your Gravel Needs
Calculate gravel volume and estimated weight using project dimensions, depth, waste allowance, material density, and optional material cost.
Project area: —
Base gravel volume: —
Waste allowance: —
Estimated gravel weight: —
Estimated material cost: —
Gravel weight varies by stone type, particle size, moisture, compaction, and supplier. The default density is a general planning estimate rather than a product-specific value. Use your supplier's published bulk density when available. US weight is shown in short tons; metric weight is shown in metric tonnes. Currency selection only changes how your entered price is displayed; no exchange-rate conversion is performed.
Gravel Is Usually Bought by Volume or Weight
A gravel estimate starts with the amount of space the material must fill. For a rectangular area, that means multiplying the project length by its width and then multiplying the area by the planned gravel depth.
In US units, the calculator converts the result into cubic yards. In metric units, the result is shown in cubic metres.
Volume = length × width × depth
Because gravel suppliers may sell material by either volume or weight, the calculator also converts the recommended volume into an estimated tonnage using the bulk-density value you enter.
Depth Has a Big Effect on the Amount of Gravel You Need
Even a small change in gravel depth can noticeably change the final material quantity because the depth is applied across the entire project area.
For example, a 200-square-foot area at 2 inches deep uses only half the base volume of the same area at 4 inches deep.
The correct depth depends on the project, the existing base, expected loads, drainage requirements and the type of gravel being used. Use the depth specified by your project plan, contractor or material supplier when available.
Do not use the calculator’s default inputs as a recommendation for construction depth. They are only starting values for estimating.
Why Gravel Density Matters
Two gravel products can occupy the same volume but weigh different amounts. Stone type, particle size, moisture, void space and compaction can all affect bulk density.
The calculator starts with a general planning value of 1.4 short tons per cubic yard in US mode. In metric mode, the equivalent default is approximately 1,661 kg/m³.
That default is not meant to replace product data. If your supplier gives you a bulk density or a weight-per-volume figure for the exact gravel you are buying, enter that value instead.
Estimated weight = recommended gravel volume × bulk density
Why Add a Waste Allowance?
The exact amount of gravel delivered and the amount finally needed on site may not match the theoretical volume perfectly.
A waste allowance can provide a planning buffer for uneven excavation, grading differences, spreading losses, settlement and small measurement errors.
The calculator defaults to 10%, but you can change that value to match your own project conditions.
Recommended volume = base volume × (1 + waste percentage)
Worked Example: A 20 × 10 Foot Gravel Area
Suppose you are planning a rectangular gravel area with these inputs:
- Length: 20 ft
- Width: 10 ft
- Depth: 4 in
- Waste allowance: 10%
- Bulk density: 1.4 tons per cubic yard
- Price per ton: $50
The project area is 200 sq ft. At 4 inches deep, the base gravel volume is approximately 2.47 cubic yards.
After adding a 10% waste allowance, the recommended volume becomes approximately 2.72 cubic yards.
Using a density of 1.4 tons per cubic yard, that volume weighs approximately 3.80 short tons.
At $50 per ton, the estimated material cost is approximately $190.12.
Check These Details Before Ordering Gravel
Before placing an order, confirm how your supplier measures and sells the material. Supplier-specific information is more useful than relying on generic assumptions.
| Detail | What to confirm | Why it matters |
|---|---|---|
| Material type | Exact gravel or aggregate product | Different materials can have different densities and compaction behavior. |
| Bulk density | Weight per cubic yard or cubic metre | Improves the calculator’s estimated tonnage. |
| Sales unit | By ton, tonne, cubic yard, cubic metre or bag | Determines how the final estimate should be converted into an order. |
| Minimum order | Supplier or delivery minimum | You may need to purchase more than the calculated quantity. |
| Delivery limits | Truck capacity and delivery access | Large orders may require more than one load or special site access. |
How the Cost Estimate Works
If you enter a price per ton in US mode, the calculator multiplies the estimated short tons by your entered price.
In metric mode, the price field changes to price per metric tonne and the estimated metric-tonne quantity is used.
Estimated cost = estimated gravel weight × price per ton or tonne
The estimate covers the material value only. Delivery charges, taxes, equipment rental, excavation, base preparation, geotextile, labor and other project costs are not included unless they are already built into the supplier price you enter.
When This Calculator Needs an Adjustment
The calculator assumes one rectangular project area with a consistent gravel depth.
For irregular projects, divide the site into smaller rectangles, estimate each section separately and add the results together.
You may also need a more project-specific calculation when dealing with:
- changing gravel depths across the site;
- sloped or heavily uneven ground;
- multiple gravel layers with different materials;
- large excavation or fill projects;
- projects where final compacted volume is specified by an engineer or contractor;
- supplier products sold using a product-specific coverage rate rather than bulk volume.
For nearby outdoor materials, you can also use the Paver Calculator or Concrete Calculator.
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