Gravel CalculatorPea Gravel, Crushed Rock & Landscape Rock Calculator
Gravel how much do I need? This free gravel calculator takes the guesswork out of figuring gravel for driveways, paths, gardens, and landscaping jobs. It works as a pea gravel calculator, crushed rock calculator, landscape rock calculator, and driveway gravel calculator all in one. Enter the area dimensions and depth, choose your material type, and get instant results in tons, cubic yards, and an optional cost estimate. Use this gravel calculator yards tool to figure yards of gravel and figure out yards of gravel needed for any project.
Getting started
How to use this online gravel calculator
1
Choose your material
Crushed stone is for driveways and base layers. Pea gravel works for paths. Decomposed granite is popular for landscaping.
2
Select unit system
Imperial uses feet and inches; metric uses meters and centimeters.
3
Enter dimensions
Measure the length and width of the area. For irregular shapes, break them into rectangles.
4
Enter depth
Use 2-3 inches for decorative coverage, 4-6 inches for driveways, and up to 12 inches for a structural base.
The calculation
Step-by-step: how your gravel quantity was calculated
1
Convert depth from inches to feet
Depth (ft) = Depth (in) / 12
= 4 / 12
2
Calculate volume in cubic feet
Volume = Length x Width x Depth (ft)
= 40 x 12 x 0.333
3
Convert to cubic yards
Cubic yards = ft³ / 27
= 160 / 27
4
Convert to tons (Crushed Stone / Gravel density: 1.5 t/yd³)
Tons = yd³ x density
= 5.93 x 1.5
Note: Crushed Stone / Gravel density is approximately 1.5 short tons per cubic yard.
Formulas
Gravel calculation formula
The online gravel calculator works in three steps: volume calculation, unit conversion, and weight conversion. Whether you need a pea gravel calculator for garden paths or a crushed rock calculator for a structural base, the formula is the same.
Imperial: Volume (ft³) = Length (ft) x Width (ft) x Depth (in) / 12
Volume (yd³) = ft³ / 27
Weight (tons) = yd³ x density (tons/yd³)
Metric: Volume (m³) = Length (m) x Width (m) x Depth (cm) / 100
Weight (tonnes) = m³ x density (t/m³)
Reference Table
Gravel material density reference
Densities vary by material type. Use these values to convert your volume to weight when ordering from a supplier who quotes by the ton.
Crushed stone and limestone are the densest common options. River rock is the lightest. Always confirm density with your supplier.
Depth Guide
Recommended gravel depth by project type
Using the right depth for your project prevents costly over-ordering and under-engineering. These are compacted depths - order 15-20% more loose material to achieve the target compacted depth.
For driveways, a 4-6 inch compacted base of crushed stone is the minimum. Use 6-8 inches for heavy truck traffic or poor soil drainage.
Background Information
Figuring gravel for a driveway — driveway gravel calculator guide
Gravel driveways are one of the most common uses for a driveway gravel calculator. A well-built gravel driveway needs at least two layers: a compacted base of large crushed stone (57 limestone or 304 road base, 4-6 inches) topped with a finer surface stone (pea gravel or crusher run, 2-3 inches). Calculate each layer separately and add the totals. Use this tool as your landscape rock calculator for decorative applications or as a crushed rock calculator for structural fill.
Why suppliers sell by weight, not volume
Gravel and crushed stone are sold by the ton because weight is easy to verify at the truck scale and is consistent regardless of how the material was loaded. Volume varies with particle size, moisture content, and compaction. When the supplier quotes a price "per ton," use this calculator to convert your volume to tons first, then multiply by the price.
Context
Quick tips for gravel projects
Always order 10-15% more than calculated
Gravel compacts when tamped or driven over. Without a compaction buffer you will run short before the project is done.
Calculate multi-layer projects layer by layer
A driveway with a crushed-stone base and a pea-gravel surface uses different material and depth for each layer - run the calculator separately for each and add the totals.
Match material to application
Crushed stone is for structural bases; pea gravel works for drainage and decorative paths; river rock is for ornamental beds. Using the wrong type causes premature failure or wasted spend.
Examples
Worked examples
Example 1 - Driveway (imperial)
A 12 ft x 50 ft driveway at 4 inches of crusher-run gravel: depth = 4/12 = 0.333 ft; volume = 12 x 50 x 0.333 = 200 ft³ = 7.41 yd³. At 1.5 tons/yd³: 11.1 tons. With 12% compaction buffer: order 12.5 tons.
Example 2 - Garden path (metric)
A 15 m x 1.2 m garden path at 8 cm of pea gravel: depth = 0.08 m; volume = 15 x 1.2 x 0.08 = 1.44 m³. At 1.52 t/m³ (pea gravel): 2.19 tonnes. Add 10% compaction: order 2.4 tonnes.
Example 3 - Decorative bed (imperial)
A 20 ft x 8 ft flower bed at 3 inches of river rock: volume = 20 x 8 x 0.25 = 40 ft³ = 1.48 yd³. At 1.3 tons/yd³: 1.92 tons. Order 2 tons.
Mistakes
Common mistakes when figuring gravel
Using volume instead of weight
Suppliers quote tons. Always convert volume to weight using the density factor.
Not accounting for compaction
Gravel compacts 10-15% when tamped or driven over. Order 10-15% more than the loose calculation shows.
Wrong depth for the application
Two inches works for decoration; it does not work for a driveway. Use the recommended depths above.
FAQ
Frequently asked questions
Q
How do I figure out how much gravel I need?
Multiply the length by the width to get the surface area, then multiply by the depth to get volume. In imperial: use feet for length and width, and inches for depth (divide depth by 12 to convert to feet first). Divide the cubic footage by 27 to get cubic yards. Then multiply cubic yards by the gravel density - typically 1.5 tons/yd³ for crushed stone - to get tons. Add 10-15% for compaction and spillage.
Q
How many yards of gravel do I need for a driveway?
A typical residential driveway is 12 ft wide x 40 ft long with a 4-inch thick base. Volume: 12 x 40 x (4/12) = 160 ft³ = 5.93 yd³. At 1.5 tons/yd³, that is about 8.9 tons of crushed stone. Most suppliers recommend a 4-6 inch compacted depth for driveways, so figure 6-10 tons for a standard driveway.
Q
How much does a yard of gravel cover?
One cubic yard of gravel covers approximately 100 sq ft at 3 inches deep, 81 sq ft at 4 inches, or 162 sq ft at 2 inches. Use the formula: Coverage (sq ft) = 27 x 12 / Depth (inches). A ton of average-density gravel covers roughly 67-70 sq ft at 4 inches deep.
Q
What is the difference between crushed stone and pea gravel?
Crushed stone has angular edges that lock together when compacted - ideal for driveways, base layers, and structural fill. Pea gravel has smooth, rounded edges that don't compact as well but are comfortable underfoot - better for pathways, playgrounds, and decorative landscaping. Pea gravel is also slightly lighter per cubic yard (about 1.4 tons vs. 1.5 tons for crushed stone).
Q
How deep should gravel be for a driveway?
For a residential gravel driveway, a minimum of 4 inches of compacted gravel is recommended, though 6 inches is better for areas with heavy vehicles or poor drainage. Use a base layer of compacted crushed stone (57 limestone or 304 road base) topped with a finer gravel or pea gravel layer for appearance. Total depth before compaction should be 5-8 inches to achieve a 4-6 inch compacted base.
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