Calculator
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MathGravel Calculator
Free gravel calculator: find how much gravel you need for a driveway or path in cubic yards, tons and bags, plus the total cost with a waste/compaction margin.
The Gravel Calculator helps you estimate the amount of gravel, crushed stone, or aggregate needed for your project. Enter area dimensions and depth to calculate volume, weight, and number of bags required.
Have feedback? Report bugs, suggest features, or share your thoughts — we read them allWhat is a Gravel Calculator?
A Gravel Calculator is a practical tool for landscaping, construction, and home improvement projects that estimates the quantity of gravel, crushed stone, or aggregate materials needed to cover a specific area to a desired depth. By entering the dimensions of your project area and the depth of gravel required, the calculator determines the volume in cubic yards or meters, weight in tons, and the number of bags needed, helping you purchase the correct amount and avoid waste.
How to Use the Gravel Calculator
- Select project type: rectangular (for driveways, paths) or circular (for features, ponds)
- Enter the area dimensions in your preferred unit (length × width or diameter)
- Specify the depth of gravel you want to apply (typically 2-4 inches or 5-10 cm)
- Choose the type of gravel - each has different density affecting weight
- Select the bag size if purchasing in bags rather than bulk
- Set the waste / compaction % so the recommended order covers settling and spillage
- Optionally enter a price and pick per tonne, per yd³ or per bag to estimate total project cost
- Click Calculate to see volume, weight, bags, the recommended order quantity and total cost
Gravel Calculation Formulas
1. Rectangular Volume = Length × Width × Depth
2. Circular Volume = π × (Diameter/2)² × Depth
3. Weight = Volume × Density
4. Bags Needed = Weight / Bag Size
Recommended Gravel Depths
Driveway: 4-6 inches (10-15 cm) for vehicles
Walkway/Path: 2-3 inches (5-8 cm) for foot traffic
Drainage: 4-8 inches (10-20 cm) for French drains
Decorative: 2-4 inches (5-10 cm) for garden beds
Tips for Gravel Projects
- Add 5-10% extra gravel to account for settling and compaction
- Use landscape fabric underneath to prevent weeds and mixing with soil
- Compact gravel in layers for driveways - don't pour all at once
- Pea gravel is smooth and good for paths, crushed stone better for driveways
- Deeper gravel provides better drainage and stability
- Edge your gravel area with pavers or border stones to contain material
- 1 cubic yard of gravel typically covers 100 sq ft at 3 inches deep
About Gravel Types
Gravel comes in many types, each suited for different applications. Pea gravel (small, rounded stones) is comfortable for walkways and decorative landscaping. Crushed stone (angular fragments) compacts well and is ideal for driveways and base layers. River rock (smooth, larger stones) works well for drainage and decorative features. Limestone and granite are durable crushed stones for high-traffic areas. Lava rock is lightweight and excellent for drainage and decorative mulch. The stone size typically ranges from 1/4 inch to 2 inches in diameter.
Common Gravel Estimation Mistakes
- Not accounting for compaction - gravel settles 10-20% over time
- Using insufficient depth for the application
- Forgetting to prepare the base with landscape fabric
- Not adding extra material for waste and settling
- Choosing wrong gravel type for the application
- Underestimating how much volume small areas need at proper depth
Frequently Asked Questions
A gravel calculator turns project dimensions into the volume of gravel in cubic yards or cubic meters, and converts that volume into tons based on the specific gravel type and density. You enter length, width, and depth (typically 2 to 6 inches for driveways), and select the gravel type (pea gravel, crushed stone, river rock, decomposed granite). The tool multiplies area by depth, divides by 27 to get cubic yards, then multiplies by the material density (1.4 to 1.7 tons per cubic yard depending on type) to give tonnage for ordering. It saves you from over-ordering bulk loads that cost 50 to 100 dollars in delivery fees.
Use it for driveways, French drains, drainage layers under slabs, landscaping paths, parking pads, paver bases, and any project ordering more than half a yard of bulk gravel. Bag versus bulk economics flip around 8 to 10 cubic yards. The calculator is essential when mixing layers (open-graded base under compactable choke layer under fines), comparing material types (crushed stone packs tighter than rounded river rock), and pricing delivery (gravel weighs 2800 to 3400 lbs per yard, exceeding pickup capacity at 1 cubic yard). It also helps when ordering by tonnage from quarries that price per ton rather than per yard.
Most calculators accept feet/inches or meters/centimeters for dimensions, with output in cubic yards, cubic meters, tons (US short ton 2000 lb), or metric tonnes (1000 kg). Gravel densities vary: pea gravel 1.4 tons per cubic yard, crushed limestone 1.5, granite 1.6, washed river rock 1.4, decomposed granite 1.7 (compacted). Common gradations are 3/8 inch pea, 3/4 inch crushed (driveway base), 1.5 inch railroad ballast, and number 57 stone (drainage). Mixing yard volumes with ton prices without applying density gives errors of 30 to 70 percent.
Cubic feet equals area in sq ft times depth in feet. Divide by 27 for cubic yards, then multiply by tons per cubic yard for the material. Example: a 20 by 30 ft driveway at 4 inch depth = 600 sq ft × 0.333 ft = 200 cubic feet, divide by 27 = 7.4 cubic yards. For crushed stone at 1.5 tons per yard, that is 11.1 tons. Add 5 to 10 percent for compaction settlement, more for sloped sites where gravel migrates. Driveways typically need 4 to 6 inches of compacted base, with 2 inch finish layer on top, so calculate base and finish separately if you are layering.
Three common gotchas: first, compaction. Loose gravel compacts 15 to 25 percent under traffic, so a 4 inch installed depth needs 5 inches of loose material to start. Second, edge spillover. Driveways without curbs lose 10 to 15 percent over years as gravel migrates to lawns and gutters; ordering tight means topping up annually. Third, density confusion. Quarries sell by ton, calculators output yards. A short ton (2000 lb) of crushed stone is roughly 0.67 cubic yards, not 1 yard, so converting wrong cuts your order by a third. Always confirm whether quotes are yards or tons, and request the specific material's tons-per-yard factor.
Driveway base: 3/4 inch crushed stone or crusher run (mix of fines for compaction). Driveway top: 3/8 inch pea or chip seal. Drainage (French drain): washed 1.5 inch with no fines so water flows. Paver base: 3/4 inch crushed compacted, then 1 inch sand setting bed. Concrete slab subbase: 1 inch open graded crushed (allows drainage under slab). Decorative paths: 3/8 inch pea or 1/2 inch river rock for appearance over weed fabric. Avoid round river rock for driveways because tires displace it. Avoid limestone in acidic soils; it dissolves. Match aggregate to job specs from the engineer or designer.
Yes. AASHTO M43 and ASTM C33 define aggregate gradations for concrete and base courses. State DOTs publish gradation specs (Caltrans Class 2 Aggregate Base, NYSDOT Item 304) for road and driveway use. For permitted driveways crossing public rights-of-way, follow local approach permit specs (typically 4 to 6 inch compacted base of dense graded aggregate plus pavement). LEED v4 SS Heat Island Reduction credit favors high-SRI gravels (light-colored crushed limestone reflects more than dark basalt). For drainage, ASTM C33 #57 stone is the standard for septic drain fields and French drains. Avoid recycled concrete aggregate in drinking water catchments because of pH leaching.
Bulk gravel runs 25 to 80 USD per cubic yard at the quarry, plus 50 to 150 USD delivery within 15 miles. Premium decorative river rock and colored basalt can hit 150 to 300 USD per yard. A 10-ton dump truck delivers about 6 to 7 cubic yards depending on gravel type. Bagged gravel from big-box stores costs 6 to 12 USD per 0.5 cubic foot bag, working out to 320 to 650 USD per yard, which is 5 to 10 times bulk pricing. Use bags only for tiny jobs (under 1 yard) where bulk delivery fees outweigh material savings, or when access is too tight for a dump truck.
Use the Waste / Compaction % field to add a margin on top of the exact volume. A typical 10% covers settling, spillage and minor over-excavation. For driveways where loose gravel compacts 15 to 25% under traffic, set 15 to 20% so the installed compacted depth still meets spec. Sloped or curbless sites lose more to migration, so 20 to 25% is safer there. The calculator applies your percentage to volume, tonnage and bag count at once, so the Recommended Order line is the figure you actually order from — never the bare theoretical volume, which always leaves you short.
Match the price unit to how your supplier quotes. Quarries usually price per (short or metric) ton, while landscape yards and bagged products price per cubic yard or per bag. Pick the matching option in the price selector and the tool multiplies it by the overage-adjusted quantity in that same unit, so you avoid the classic 30 to 70% error of multiplying a per-ton price by a yard volume. The tonnage output here is metric tonnes (1000 kg); a US short ton is 907 kg, about 10% lighter, so confirm which ton your quote uses before comparing. For tiny jobs, switch to per bag to test the bulk-versus-bag crossover, which usually flips around 8 to 10 cubic yards.
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