🪨 Gravel Calculator: How Much Gravel Do I Need?
By Shihab Mia · Updated 2026-07-18
Assumes a typical gravel density of about 1.4 US tons per cubic yard. Loose gravel, crushed stone, and wet material vary, so adjust the density to match your supplier's figure. The waste allowance covers spillage, compaction, and uneven ground.
This gravel calculator tells you exactly how much gravel you need to fill an area to a chosen depth, in cubic yards, cubic metres, tons, and bags. Enter length, width, and depth and it returns the volume plus an estimated weight and order quantity in seconds. As a quick default, a 20 ft by 10 ft area at 4 inches deep needs about 2.47 cubic yards, roughly 3.46 US tons, or about 2.72 cubic yards once a 10 percent waste allowance is added. You can switch between imperial (feet and inches) and metric (metres) units, tune the gravel density to match your supplier, add a price per ton or per yard to see the cost, and set your own waste percentage so you order enough to finish the job.
What is the Gravel Calculator?
Estimating gravel starts with volume. The space you are filling is a flat box, so its volume is simply length times width times depth. The only catch is keeping units consistent. In imperial work the length and width are usually in feet while the depth is in inches, so the depth is divided by 12 to turn it into feet before multiplying. The result is a volume in cubic feet, which is then divided by 27 (a cubic yard is 3 feet on each side, and 3 x 3 x 3 = 27 cubic feet) to give cubic yards, the unit most gravel suppliers quote. This gravel calculator handles that conversion for you, so you can enter feet and inches together without doing the arithmetic by hand.
Gravel is also sold by weight, so the calculator converts volume to tons using a density figure. Density is how much a unit of volume weighs, and for common dry gravel and crushed stone it sits around 1.4 US tons per cubic yard, although the US Geological Survey and most aggregate suppliers note it can range from about 1.4 to 1.7 tons depending on stone type, particle size, and moisture. Multiplying the cubic yards by the density gives the weight in tons. The tool also shows metric tonnes for international suppliers, since one US ton is about 0.907 metric tonnes and 1.4 US tons per cubic yard works out to roughly 1.66 tonnes per cubic metre.
Many suppliers sell smaller quantities in bags rather than by the truckload, so a good gravel calculator also converts your volume into bags. A standard bag holds about 0.5 cubic feet, which means a 50 lb bag covers only about 3 square feet at 2 inches deep. Filling a 100 square foot area to 4 inches deep takes roughly 67 of those bags, which is why bulk delivery by the cubic yard or ton is far cheaper for anything larger than a small border or planter. The calculator shows the bag count alongside the yardage so you can compare bagged and bulk pricing before you buy.
Cost is usually the number people really care about. Once you know the tonnage, a price estimate is just weight times the rate your supplier charges, though delivery, spreading, and compaction are billed separately. Add your price per ton or per cubic yard and the gravel calculator multiplies it by the order quantity so you get a material budget instantly. Because prices swing with location, fuel, and stone type, always confirm the current rate with your quarry or landscape yard before committing to an order.
Real jobs are never perfectly flat or perfectly efficient, so it pays to order a little extra. Material is lost to spillage, gets pressed into soft or uneven ground, and compacts once it is raked and rolled. A waste allowance of around 5 to 15 percent is a sensible default for most driveways and paths, with 10 percent a safe middle ground. The gravel calculator applies your chosen percentage on top of the bare volume so the order quantity already includes that cushion, which is almost always cheaper than a second delivery for the last few square feet.
Depth matters as much as area. A decorative gravel top-dressing only needs 2 to 3 inches, but a driveway that carries vehicle weight usually wants a 4 to 6 inch base, and soft or clay ground may need a deeper sub-base still. Because volume scales directly with depth, doubling the depth doubles the gravel and doubles the cost, so getting the depth right is the single biggest lever on how much gravel you need. Use the reference tables below to pick a sensible depth for your application, then let the calculator turn it into yards, tons, bags, and dollars.
When to use it
- Working out how many cubic yards, tons, or bags of gravel to order for a driveway, path, or patio base.
- Filling a French drain, soakaway, or trench to a set depth with the right amount of stone.
- Budgeting a landscaping job by turning an area and depth into a tonnage and a material cost to price up.
- Choosing between bagged and bulk gravel by comparing the bag count against a cubic yard delivery.
- Checking a supplier or contractor quote by estimating the gravel volume, weight, and price yourself.
- Planning decorative gravel, pea gravel, or crushed stone beds where depth and coverage per ton matter.
How to use the Gravel Calculator
- Pick imperial units (feet and inches) or metric units (metres).
- Enter the length and width of the area, then the depth you want to fill.
- Adjust the gravel density if your supplier quotes a different tons-per-cubic-yard figure for your material.
- Optionally add a price per ton or per cubic yard to see the estimated cost.
- Set a waste allowance percentage, then read off the volume in cubic yards and metres, the weight in tons, the bag count, and the total cost.
Formula & method
Worked examples
You are spreading gravel over a 20 ft by 10 ft driveway to a depth of 4 inches.
- Convert the depth to feet: 4 / 12 = 0.3333 ft
- Volume in cubic feet = 20 x 10 x 0.3333 = 66.67 cubic feet
- Cubic yards = 66.67 / 27 = 2.47 cu yd
- Cubic metres = 2.47 x 0.7646 = 1.89 cubic metres
- Weight = 2.47 x 1.4 = 3.46 US tons (about 3.14 metric tonnes)
- Bags at 0.5 cu ft each = 66.67 / 0.5 = 134 bags
- Add a 10% waste allowance: 2.47 x 1.10 = 2.72 cu yd, about 3.80 US tons to order
Result: approx 2.47 cu yd (1.89 cubic metres), approx 3.46 US tons or 134 bags, rising to about 2.72 cu yd and 3.80 tons once 10% waste is added.
You are filling a metric area 6 m long by 3 m wide to a depth of 0.1 m (10 cm).
- Volume in cubic metres = 6 x 3 x 0.1 = 1.8 cubic metres
- Cubic yards = 1.8 / 0.7646 = 2.35 cu yd
- Weight = 2.35 x 1.4 = 3.30 US tons
- Convert to tonnes: 3.30 x 0.9072 = 2.99 metric tonnes
- Add a 10% waste allowance: 2.35 x 1.10 = 2.59 cu yd, about 3.63 US tons to order
Result: approx 1.8 cubic metres (2.35 cu yd), approx 3.30 US tons (2.99 tonnes), rising to about 2.59 cu yd and 3.63 tons once 10% waste is added.
You want a rough cost for the driveway above at a supplier price of 30 US dollars per ton delivered.
- Start from the order quantity with waste: 3.80 US tons
- Multiply by the price per ton: 3.80 x 30 = 114 US dollars
- Remember delivery, spreading, and compaction are usually billed on top of the material rate
Result: About 114 US dollars in gravel for the 20 ft by 10 ft driveway at 30 dollars per ton, before delivery and labour.
Gravel needed to cover 100 square feet at common depths (density 1.4 tons per cubic yard)
| Depth | Cubic feet | Cubic yards | US tons | Bags (0.5 cu ft) |
|---|---|---|---|---|
| 2 in | 16.67 | 0.62 | 0.86 | 34 |
| 3 in | 25.00 | 0.93 | 1.30 | 50 |
| 4 in | 33.33 | 1.23 | 1.73 | 67 |
| 6 in | 50.00 | 1.85 | 2.59 | 100 |
Roughly how much area one US ton of gravel covers (density 1.4 tons per cubic yard)
| Depth | Coverage per ton (sq ft) |
|---|---|
| 1 in | approx 231 |
| 2 in | approx 116 |
| 3 in | approx 77 |
| 4 in | approx 58 |
| 6 in | approx 39 |
Typical loose densities of common aggregates (approximate)
| Material | US tons per cubic yard | Metric tonnes per cubic metre |
|---|---|---|
| Dry gravel / crushed stone | 1.4 | 1.66 |
| Pea gravel | 1.3 | 1.55 |
| Sand (dry) | 1.3 | 1.55 |
| River rock | 1.35 | 1.60 |
| Wet gravel | 1.5 | 1.79 |
Suggested gravel depth by application
| Application | Typical depth |
|---|---|
| Decorative top-dressing / mulch bed | 2 to 3 in |
| Garden path or walkway | 2 to 4 in |
| Driveway wearing layer | 3 to 4 in |
| Driveway base over sub-base | 4 to 6 in |
| Base over soft or clay ground | 6 to 10 in (often in layers) |
Common mistakes to avoid
- Mixing up the depth units. In imperial work the length and width are in feet but the depth is usually in inches. If you forget to divide the depth by 12, you overestimate the volume by twelve times. Keep every measurement in the same unit before multiplying, or let the gravel calculator handle the conversion for you.
- Treating one density figure as fixed. Around 1.4 tons per cubic yard is a fair average for dry gravel, but pea gravel is lighter and wet or compacted stone is heavier, with real values spanning roughly 1.4 to 1.7 tons. If your supplier publishes a density, use it, because a 10 percent density error feeds straight through to the tonnage you order and pay for.
- Ordering the exact volume with no spare. Bare volume assumes perfect ground and zero loss. In practice gravel spills, sinks into soft soil, and settles when compacted, often by 10 to 20 percent. Skipping the waste allowance leaves you short, and a top-up delivery can cost more than the extra material itself.
- Confusing US tons with metric tonnes. A US (short) ton is 2,000 pounds while a metric tonne is about 2,205 pounds, so they differ by roughly 10 percent. Check which one your supplier quotes before comparing prices, since the calculator shows both figures side by side.
- Buying bags for a big area. Bagged gravel is convenient but expensive per cubic foot. A 100 square foot area at 4 inches deep needs about 67 half-cubic-foot bags, which is heavier to haul and usually pricier than a single bulk delivery. Compare the bag count against a cubic yard order before deciding.
- Measuring an irregular area as one big rectangle. Curved beds, tapered driveways, and L-shaped patios are not simple rectangles. Split an odd shape into rectangles, triangles, or circles, calculate each piece, and add them up, otherwise you can over or under order by a wide margin.
Glossary
- Cubic yard
- A volume measuring 3 feet on each side, equal to 27 cubic feet. The unit most gravel suppliers use for ordering.
- Density
- How much a unit of volume weighs. For gravel it is usually given in tons per cubic yard or tonnes per cubic metre.
- US ton
- A short ton equal to 2,000 pounds, about 0.907 metric tonnes. Common in the United States.
- Metric tonne
- A unit of 1,000 kilograms, about 2,205 pounds, used by most suppliers outside the United States.
- Waste allowance
- An extra percentage added to the calculated volume to cover spillage, compaction, and uneven ground.
- Coverage
- The area a given amount of gravel spreads over at a set depth, often quoted as square feet per ton.
- Pea gravel
- Small, rounded stones about the size of a pea, popular for paths and decorative beds and slightly lighter than crushed stone.
- Sub-base
- A lower layer of coarse aggregate that spreads load and improves drainage beneath a gravel or paved surface.
Frequently asked questions
How much gravel do I need?
Multiply the area length by its width and by the depth in matching units to get the volume, then divide cubic feet by 27 to get cubic yards. A 20 by 10 foot area at 4 inches deep needs about 2.47 cubic yards or 3.46 US tons. The calculator does this instantly and also adds a waste allowance.
How do I convert cubic yards of gravel to tons?
Multiply the cubic yards by the gravel density. A common figure for dry gravel and crushed stone is about 1.4 US tons per cubic yard, so 2.47 cubic yards weighs roughly 3.46 tons. Adjust the density in the calculator to match your supplier for a more exact result.
How much area does 1 ton of gravel cover?
At a density of 1.4 tons per cubic yard, one US ton of gravel covers about 116 square feet at 2 inches deep, 58 square feet at 4 inches deep, and 39 square feet at 6 inches deep. Coverage halves as you double the depth, so always match the figure to your planned depth.
How many bags of gravel are in a cubic yard?
A cubic yard is 27 cubic feet, so at 0.5 cubic feet per bag that is about 54 bags. Filling a 100 square foot area to 4 inches deep takes roughly 67 bags. For anything larger than a small bed, a bulk cubic yard delivery is usually far cheaper than bagged gravel.
What density does this gravel calculator assume?
It defaults to about 1.4 US tons per cubic yard, a typical value for dry gravel and crushed stone. Pea gravel is a little lighter and wet or heavily compacted stone is heavier, so you can change the density field to whatever your material supplier publishes.
How deep should a gravel layer be?
A decorative gravel top layer is often 2 to 3 inches deep, while a driveway base typically needs 4 to 6 inches, sometimes more over soft ground. Choose the depth your project calls for and the calculator works out the matching volume and tonnage.
How much does gravel cost?
Bulk gravel commonly runs from about 25 to 65 US dollars per ton depending on stone type, location, and volume, plus delivery. Enter your supplier price per ton or per cubic yard in the calculator and it multiplies it by your order quantity to estimate the material cost.
Why should I add a waste allowance?
Real ground is uneven and some material is always lost to spillage and compaction, so the bare volume usually falls short. A waste allowance of around 5 to 15 percent gives a cushion so you do not run out near the end and need a costly extra delivery.
Does this work for crushed stone, sand, or pea gravel?
Yes. The volume calculation is the same for any loose material that fills an area to a depth. To get an accurate weight, set the density field to the value for your material, since sand, pea gravel, river rock, and crushed stone each weigh slightly differently per cubic yard.
How do I calculate gravel for a circular or irregular area?
For a circle, use area = 3.1416 x radius squared, then multiply by depth. For odd shapes, split them into rectangles, triangles, and circles, work out each piece separately, and add the volumes together before converting to yards and tons.