Gravel Calculator
Gravel & Aggregate Calculator
Estimate aggregate for base layers, driveways, paths, and landscaping beds. Enter area and compacted thickness, apply a compaction factor and waste allowance to get your order volume — then optionally convert to tonnes using bulk density.
Gravel & Aggregate Calculator
Estimate order volume and weight with waste and compaction
Results
Enter values above to calculate
How the Calculation Works
You order loose aggregate that will compact down to the finished depth. The diagram shows the three key depths and how they relate.
Step-by-Step Formulas
1. Calculate Area
Start with the footprint of the area to fill. Use length × width for rectangular pads, driveways, and paths — or diameter for circular pads and round features.
2. Compacted Volume
Thickness is the finished (compacted) depth of the base or fill layer. In metric enter centimetres; in imperial enter inches.
3. Compaction Factor
Because aggregate compacts under traffic and equipment, you must order more loose material than the finished compacted volume. A factor of 1.10 means order 10% extra to achieve the desired compacted depth.
4. Waste Allowance
Add waste for grading, spillage, uneven subgrade, and small measurement errors. 10% is a common starting point for simple rectangular areas.
5. Estimate Weight
Many suppliers price aggregate by the ton/tonne. Bulk density varies by material type, gradation, and moisture. Enter a supplier-specific value or use the material presets.
Typical Bulk Densities by Material
| Material | Metric | Imperial |
|---|---|---|
| Pea gravel | 1,500–1,600 kg/m³ | 94–100 lb/ft³ |
| Crushed stone (¾ in / 20 mm) | 1,600–1,700 kg/m³ | 100–106 lb/ft³ |
| Crushed stone (base aggregate) | 1,650–1,750 kg/m³ | 103–109 lb/ft³ |
| Sand (dry) | 1,450–1,600 kg/m³ | 91–100 lb/ft³ |
| Sand (wet) | 1,700–2,000 kg/m³ | 106–125 lb/ft³ |
| River gravel (rounded) | 1,550–1,650 kg/m³ | 97–103 lb/ft³ |
* Values are dry bulk densities and are indicative. Confirm with your supplier for accurate weight pricing.
Worked Example
Gravel base for a 10 m × 3 m pad, 10 cm compacted thickness, compaction factor 1.10, 10% waste, density 1,600 kg/m³.
Volume, Weight and Compaction
Aggregate is ordered by weight but measured by volume, and the bridge between them catches people out:
- Density Converts Volume to Tons: Suppliers sell by the ton while you measure cubic yards. Multiplying by bulk density is the conversion, and using the right density for your material is what makes the ton figure trustworthy.
- Depth Matters More Than Area: Going from 3 to 4 inches deep adds a third to the order on the same footprint. Settling the depth before you measure area is what keeps the estimate stable.
- Loose Volume Compacts Away: Quoted densities are for loose material. A compacted base consumes roughly 20–25% more than the loose figure, so a driveway base ordered on loose volume will come up short.
Benefits of Using This Calculator
Example Calculations
Three scenarios worked through step by step:
Example 1 — Driveway Top Course
Driveway 40 ft × 12 ft at 4 in deep, density 105 lb/ft³, 10% waste.
Area = 40 × 12 = 480 ft²; depth = 4 ÷ 12 = 0.333 ft
Volume = 480 × 0.333 = 160 ft³ = 5.93 yd³
With 10% waste = 6.52 yd³
Weight = 176 ft³ × 105 = 18,480 lb
Tons = 18,480 ÷ 2,000 = 9.24 tons
Example 2 — Garden Path
Path 60 ft × 3 ft at 3 in deep, density 105 lb/ft³, 10% waste.
Area = 60 × 3 = 180 ft²; depth = 0.25 ft
Volume = 180 × 0.25 = 45 ft³ = 1.67 yd³
With 10% waste = 1.83 yd³
Weight = 49.5 × 105 = 5,198 lb = 2.6 tons
Result: about 2.6 tons delivered
Example 3 — Compacted Base
Base 30 ft × 20 ft at 6 in compacted, 25% compaction allowance.
Compacted volume = 600 × 0.5 = 300 ft³ = 11.1 yd³
Loose volume needed = 11.1 × 1.25 = 13.9 yd³
Weight = 375 ft³ × 105 = 39,375 lb = 19.7 tons
Result: order about 20 tons
Compaction is why loose exceeds finished volume
Ordering Tip
Ordering Tip
Ask your supplier for the actual bulk density of the specific product rather than accepting a generic figure. Pea gravel, crusher run, and washed river stone differ by more than 20% in weight per cubic yard, and on a twenty-ton order that gap is several hundred dollars and a partly covered driveway.
Frequently Asked Questions
- Should I order gravel by volume or by weight?
- Both are common. Landscapers often order by cubic yards/metres, while many suppliers sell by the ton/tonne. Weight depends on the bulk density and moisture of the material.
- What compaction factor should I use for gravel base?
- A compaction factor of 1.10 is a common rule of thumb for granular base. Actual compaction varies by material, moisture, and equipment — confirm with your supplier if precision matters.
- How much waste should I add?
- For simple rectangular areas, 5–10% is often enough. For irregular shapes, slopes, or rough subgrade, 10–15% may be more realistic.
- How deep should a gravel driveway base be?
- A gravel driveway for passenger vehicles is typically 10–15 cm (4–6 in) of compacted granular base. In freeze-thaw climates or soft soils, 20 cm (8 in) or more is common.
- How many tons of gravel are in a cubic yard?
- About 1.4 tons for typical gravel at 105 lb/ft³, since a cubic yard is 27 ft³ and 27 × 105 = 2,835 lb. Denser crushed stone runs closer to 1.5 tons and lighter materials somewhat less, so confirm the density.
- How deep should gravel be for a driveway?
- A total of 8 to 12 inches built in layers — a coarse base course of 4–6 in topped with 3–4 in of finer surface material. A single thin layer over soft ground will rut regardless of how good the stone is.
- How much area does a ton of gravel cover?
- Roughly 100 square feet at 2 inches deep, 70 ft² at 3 inches, or 50 ft² at 4 inches, using typical density. Coverage scales inversely with depth, so doubling the depth halves the area a ton will cover.
- What is the difference between gravel and crushed stone?
- Gravel is naturally rounded by water action, while crushed stone is mechanically broken and has angular faces. Angular stone interlocks and compacts into a stable base; rounded gravel stays loose and migrates, which suits drainage but not driveways.
- Should I order by the ton or by the yard?
- Most bulk suppliers sell by the ton, so calculate cubic yards from your measurements and convert using density. Ordering in the wrong unit is a common and expensive error, since a ton and a cubic yard are far from equivalent.
- Do I need landscape fabric under gravel?
- Usually yes. Geotextile between subgrade and stone stops the aggregate pressing down into soft soil and keeps weeds from coming up. It substantially extends how long the surface stays at full depth, for a small material cost.