Gravel Calculator
Calculate the amount of gravel, crushed stone, or landscaping rock needed. Get estimates in tons, cubic yards, and bags.
Area Dimensions
Area Shape:
Common depths: 2-3" for walkways, 4" for driveways, 6"+ for drainage
Gravel Type:
Pea Gravel Needed
3.20 tons
2.47 cubic yards
Unit Conversions:
Cubic Feet
66.67
Cubic Yards
2.47
Cubic Meters
1.888
US Tons
3.20
Metric Tons
2.90
Kilograms
2903
Cost Estimate:
Coverage Rate
At 4" depth, 1 ton of pea gravel covers approximately 63 sq ft
Gravel Types Guide
Pea Gravel
Smooth, rounded stones. Great for walkways and patios.
Crushed Stone
Angular stones that compact well. Ideal for driveways.
River Rock
Smooth decorative stones. Perfect for landscaping.
Limestone
Compacts firmly. Good base material for pavers.
Decomposed Granite
Fine texture. Excellent for pathways and xeriscaping.
Lava Rock
Lightweight volcanic rock. Great for drainage and decoration.
Recommended Depths
- • Walkways: 2-3 inches of gravel
- • Patios: 3-4 inches with compacted base
- • Driveways: 4-6 inches minimum, 8-12" for heavy vehicles
- • Drainage areas: 6+ inches
- • Decorative beds: 2-3 inches
What is a Gravel Calculator?
A gravel calculator determines the quantity of gravel, crushed stone, or landscaping rock required to cover a given area at a specified depth. It converts the area and depth into volume, then into weight (tons or kilograms) and bag count, and optionally estimates material and delivery costs. Accurate gravel estimation prevents the common problems of over-ordering — which wastes money and leaves excess material on site — or under-ordering, which causes delays and requires additional delivery charges.
Gravel is one of the most versatile construction and landscaping materials. It is used for driveways, walkways, drainage systems, pipe bedding, concrete aggregate, and decorative ground cover. Different gravel types have different densities and costs, making it important to select the right product for the application and to calculate quantities based on that product's specific weight.
The calculator supports rectangular, circular, and triangular areas and automatically converts between imperial and metric units. It accounts for the density of six common gravel types, from lightweight lava rock at 50 lbs/ft³ to heavy decomposed granite at 100 lbs/ft³, ensuring accurate weight estimates for any project.
Volume and Weight Formulas
The fundamental calculation converts area and depth into volume, then uses the material density to determine weight.
Gravel Volume and Weight
Where:
- Area= Plan area to be covered (ft²)
- Depth= Gravel depth in inches, converted to feet by dividing by 12
- Density= Unit weight of gravel (lbs/ft³), varies by type
Common Gravel Types and Densities
Different gravel types have different densities and are suited to different applications:
| Type | Density (lbs/ft³) | Best Use | Characteristics |
|---|---|---|---|
| Pea Gravel | 96 | Walkways, patios, playgrounds | Smooth, rounded stones; comfortable underfoot |
| Crushed Stone | 100 | Driveways, road base, concrete | Angular; compacts well for stable surfaces |
| River Rock | 90 | Landscaping, drainage, decorative | Smooth, natural appearance |
| Limestone | 95 | Base material for pavers, driveways | Compacts firmly; economical |
| Decomposed Granite | 100 | Pathways, xeriscaping, patios | Fine texture; natural look |
| Lava Rock | 50 | Drainage, decorative mulch alternative | Very lightweight; porous |
How to Use This Calculator
- Select Unit System: Choose feet or meters for the area dimensions.
- Choose Area Shape: Select rectangle, circle, or triangle depending on your project area.
- Enter Dimensions: For rectangles, enter length and width. For circles, enter the radius. For triangles, enter base and height.
- Set Depth: Use the slider or enter the desired gravel depth in inches. Common depths range from 2 inches for walkways to 6+ inches for drainage.
- Select Gravel Type: Choose the type of gravel or stone you plan to use. The density is automatically applied.
- Enter Price per Ton: Input the material cost per ton to get a total cost estimate including delivery.
- Review Results: The calculator shows tons needed, cubic yards, cubic feet, bag count, and a cost breakdown.
Coverage Rates by Depth
Understanding coverage rates helps verify your order. One ton of typical gravel (100 lbs/ft³) covers different areas depending on depth:
| Depth | Coverage per Ton | Typical Application |
|---|---|---|
| 2 inches | 100 sq ft | Walkways, decorative ground cover |
| 3 inches | 67 sq ft | Patios, garden paths |
| 4 inches | 50 sq ft | Driveways (light traffic) |
| 6 inches | 33 sq ft | Drainage, heavy-duty driveways |
| 8 inches | 25 sq ft | Road base, deep drainage |
These rates assume standard gravel density. Lightweight materials like lava rock will cover more area per ton, while dense materials like crushed stone will cover less.
Real-World Applications
Gravel is used across residential, commercial, and civil construction projects. Homeowners use it for driveway surfacing, French drain systems, garden bed mulching, and patio bases. Commercial projects use gravel for parking lot bases, stormwater management systems, and utility trench backfill.
Civil engineering applications include road sub-base construction, railway ballast, concrete aggregate, and erosion control. Gravel's permeability makes it an excellent drainage material — it allows water to flow through while providing structural support above.
Landscapers frequently use decorative gravel for ground cover, water features, and low-maintenance garden design. Different colors and textures of gravel can create visually appealing patterns that complement architectural styles and reduce water usage compared to traditional lawns.
Worked Examples
Rectangular Driveway
Problem:
Calculate the gravel needed for a driveway that is 20 ft long, 12 ft wide, and 4 inches deep using crushed stone.
Solution Steps:
- 1Area: 20 × 12 = 240 sq ft
- 2Depth in feet: 4 / 12 = 0.333 ft
- 3Volume: 240 × 0.333 = 80.0 cubic feet
- 4Convert to cubic yards: 80.0 / 27 = 2.96 cubic yards
- 5Weight: 80.0 × 100 lbs/ft³ = 8000 lbs = 4.0 tons
- 6At $50 per ton: material cost = $200
Result:
Order 4.0 tons of crushed stone (approximately 2.96 cubic yards) for a cost of $200 plus delivery.
Circular Garden Bed
Problem:
Fill a circular garden bed with a 6-foot radius to a depth of 3 inches using pea gravel at $45 per ton.
Solution Steps:
- 1Area: π × 6² = 113.1 sq ft
- 2Depth: 3 / 12 = 0.25 ft
- 3Volume: 113.1 × 0.25 = 28.27 cubic feet
- 4Weight: 28.27 × 96 lbs/ft³ = 2714 lbs = 1.36 tons
- 5Cost: 1.36 × $45 = $61.14
- 6Round up to 1.5 tons for waste: $67.50
Result:
Purchase 1.5 tons of pea gravel for $67.50 plus delivery.
Triangular Drainage Area
Problem:
Cover a triangular drainage area with a 15 ft base, 10 ft height, and 6-inch depth of river rock.
Solution Steps:
- 1Area: 0.5 × 15 × 10 = 75 sq ft
- 2Depth: 6 / 12 = 0.5 ft
- 3Volume: 75 × 0.5 = 37.5 cubic feet
- 4Weight: 37.5 × 90 lbs/ft³ = 3375 lbs = 1.69 tons
- 5Bags needed (0.5 cu ft each): 37.5 / 0.5 = 75 bags
Result:
Order 1.69 tons of river rock or 75 bags (0.5 cu ft each) to cover the drainage area.
Tips & Best Practices
- ✓Order 10-15 % more than calculated to account for waste, spillage, and uneven subgrade.
- ✓Compact gravel in 2-3 inch lifts for maximum density and stability on driveways and walkways.
- ✓Use landscape fabric beneath gravel to prevent weed growth and soil mixing.
- ✓Pea gravel is comfortable for walkways but does not compact well — it shifts underfoot.
- ✓Crushed stone with angular edges compacts better than rounded river rock for driveways.
- ✓Check local pricing — gravel costs vary significantly by region and delivery distance.
Frequently Asked Questions
Sources & References
Last updated: 2026-06-06
Help us improve!
How would you rate the Gravel Calculator?
Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
Formula Source: Standard Mathematical References
by Various