Measure the area first
Use length by width for a driveway or bed, the diameter for a circular fire-pit surround or tree ring, and base by height for a triangular corner. Split an irregular garden into simple shapes and add the results.
Gravel calculator
Gravel, mulch &
topsoil calculator
Turn an area and a spread depth into cubic yards, tons, cubic metres or bags. One calculator covers gravel, crushed stone, sand, bark mulch, compost and screened topsoil for rectangles, circles and triangles.
Enter measurements ↓
Based on your result
What you'll need
These quantities update after every calculation. Bulk delivery is normally cheaper above one cubic yard, while bags are easier to carry through a house or a narrow garden gate.
- Bulk material
Gravel, stone, sand, mulch, compost or topsoil by volume
- Calculate above
- Bagged alternative
Same volume ordered as sealed retail bags
- Calculate above
- Landscape fabric
Weed membrane under the bed, with lap allowance
- Calculate above
- Fabric pins
Planning figure of one pin per 8 square feet
- Calculate above
- Edging
Perimeter restraint that keeps the material in place
- Calculate above
- Edging stakes
Roughly one stake every 3 feet of edging
- Calculate above
- Excavated spoil
Soil to dig out and haul away, loose volume after swell
- Calculate above
- Drainage and edging restraint
Falls, soakaways and kerbs on vehicle areas
- As required
Delivery charges, minimum order volumes, geotextile grade and driveway sub-base build-ups vary by supplier and by site, and are not included in these quantities.
Volume guide
How this gravel calculator works
Every loose material is ordered by volume, not by area. The gravel calculator multiplies your area by the spread depth to get cubic feet, converts that figure into cubic yards or cubic metres, and then uses bulk density to show what the same load weighs in tons or tonnes.
The same maths drives the mulch calculator and topsoil calculator modes. Only the density and the sensible default depth change: bark mulch is light and spread thin, while topsoil for raised beds is heavy and often 6 to 12 inches deep.
Choose a realistic depth
Depth matters more than most people expect: doubling a 2 inch decorative layer to 4 inches doubles the order. Deep gravel drives should be built in layers rather than as one thick lift, which is what the driveway build-up mode calculates: a coarse base, a binding middle course and a clean wearing layer, each compacted in about 2 in lifts.
Convert volume into tons
Suppliers sell stone by the ton and mulch by the yard. The calculator shows both, using an editable bulk density so you can match the exact product on the quote instead of a generic average.
Allow for settlement
Loose material settles once it is raked, walked on or plate-compacted. A 5 to 20 percent allowance keeps the finished level where you want it and avoids a second small delivery.
Cubic yards, tons and bags
One cubic yard is 27 cubic feet, and it covers roughly 108 square feet at 3 inches deep or 162 square feet at 2 inches deep. Most stone yards quote gravel by the ton, so the calculator converts your volume with the bulk density you enter: about 1.4 tons per cubic yard for common crushed stone.
Bagged material is sold by volume as well. Retail bags of stone and soil are usually 0.5 to 1 cubic foot, and bark mulch bags are commonly 2 cubic feet, which means 13.5 mulch bags fill a single cubic yard. Working in metric, the same result is shown in cubic metres, tonnes and litre bags.
Bulk delivery normally becomes cheaper somewhere around one cubic yard, but access decides the answer as often as price. Check where a tipper truck can safely drop a load, and whether the material has to be barrowed through a side gate.
Mulch calculator and topsoil calculator modes
Select bark mulch and the defaults change to a light 800 lb per cubic yard at a 3 inch depth, which is the usual compromise between weed suppression and letting rain reach the roots. Keep mulch clear of trunks and stems rather than piling it against them.
For lawns and turf, screened topsoil is normally spread 2 to 4 inches deep before seeding or laying turf. For raised beds, set the depth to the internal height of the bed, or use a topsoil and compost blend and calculate each part separately.
Sand behaves differently again. Bedding sand under paving is usually 1 inch of screeded depth, while play sand and sandpits are ordered by finished depth. In every mode the volume, weight and bag count come from the same three inputs: area, depth and density.
Choosing a depth
How deep should the layer be?
Use these depths as a starting point, then adjust for traffic, drainage and the size of the stone. Larger stone needs a deeper layer to lock together.
- Decorative gravel
- 2 in over landscape fabric for beds and borders that are not walked on regularly.
- Paths and patios
- 3 in of angular stone such as #57 or crusher run, restrained with edging on both sides.
- Gravel driveways
- Two or three compacted 4 in layers, with a coarse base under a finer wearing course.
- Topsoil and mulch
- 3 in of mulch on beds, 2–4 in of topsoil for lawns, and the full internal height for raised beds.
Coverage reference
How much area does a ton of gravel cover?
Coverage depends on the bulk density of the material and the depth you spread it. The figures below are square feet covered by one US ton, and by one cubic yard, at the three most common depths.
| Material | lb / cu yd | 1 ton at 2 in | 1 ton at 3 in | 1 ton at 4 in |
|---|---|---|---|---|
| #57 crushed stone | 2,800 | 116 sq ft | 77 sq ft | 58 sq ft |
| Pea gravel | 2,800 | 116 sq ft | 77 sq ft | 58 sq ft |
| Crusher run / road base | 3,000 | 108 sq ft | 72 sq ft | 54 sq ft |
| River rock | 2,700 | 120 sq ft | 80 sq ft | 60 sq ft |
| Sand | 2,700 | 120 sq ft | 80 sq ft | 60 sq ft |
| Screened topsoil | 2,100 | 154 sq ft | 103 sq ft | 77 sq ft |
| Compost | 1,100 | 295 sq ft | 196 sq ft | 147 sq ft |
| Bark mulch | 800 | 405 sq ft | 270 sq ft | 203 sq ft |
| Any material, 1 cubic yard | — | 162 sq ft | 108 sq ft | 81 sq ft |
Wet material weighs more and covers less per ton. Confirm the delivered density with the supplier before ordering by weight, and add the compaction allowance for anything that will be walked on or driven over.
Mulch calculator for Home Depot and Lowe's bag sizes
Bagged material is sold by volume, and the volume printed on the bag is what decides how many you need. These are the sizes that sit on the shelf at the big-box stores, with the number of bags that fills one cubic yard.
| Bagged product | Bag volume | Bags per cubic yard | Bags per m³ |
|---|---|---|---|
| Bark mulch, standard bag | 2 cu ft | 14 bags | 18 bags |
| Bark mulch, large bag | 3 cu ft | 9 bags | 12 bags |
| Garden soil | 1.5 cu ft | 18 bags | 24 bags |
| Topsoil, 40 lb bag | 0.75 cu ft | 36 bags | 48 bags |
| Paver base and pea gravel, 50 lb bag | 0.5 cu ft | 54 bags | 71 bags |
| All-purpose sand, 50 lb bag | 0.5 cu ft | 54 bags | 71 bags |
Set the bag size in the calculator to match the product you are buying and the bag count updates with it. Bulk delivery is usually cheaper above roughly one cubic yard, which is 14 standard mulch bags or 54 bags of paver base — worth checking before loading a car.
The maths
From area and depth to cubic yards
Volume is simply area multiplied by depth, once the depth is converted from inches into feet. Cubic yards follow by dividing by 27, and weight follows from the bulk density of the material.
area = length × width, or π × radius², or ½ × base × height
volume (cu ft) = area × (depth ÷ 12)
cubic yards = cubic feet ÷ 27
tons = cubic yards × density ÷ 2,000
bags = cubic feet ÷ bag size, rounded up
volume (cu ft) = area × (depth ÷ 12)
cubic yards = cubic feet ÷ 27
tons = cubic yards × density ÷ 2,000
bags = cubic feet ÷ bag size, rounded up
- 01
Measure the area
Length by width, diameter, or base by height; split odd shapes into simple parts.
- 02
Set the depth
Enter inches or centimetres of finished, spread material rather than the excavation depth.
- 03
Pick the material
Density and a sensible default depth are filled in for stone, sand, soil, compost and mulch.
- 04
Add compaction
A 5 to 20 percent allowance covers settlement, raking losses and uneven ground.
- 05
Order in whole units
Volume, tonnage, bags and bulk bags are each rounded to what a supplier will actually deliver.
Before you order
Gravel and mulch questions, answered
About 162 square feet at 2 inches deep, 108 square feet at 3 inches deep and 81 square feet at 4 inches deep. One cubic yard is 27 cubic feet, so coverage falls as the layer gets deeper.
Multiply cubic yards by the bulk density and divide by 2,000. Common crushed stone is close to 2,800 lb per cubic yard, or about 1.4 tons, but wet or dense stone weighs more.
Around 3 inches for paths and drainage layers, and 4 inches per compacted layer on a driveway. #57 stone is roughly 3/4 inch angular material, so a layer thinner than about 2 inches will not lock together.
Thirteen and a half 2 cubic foot bags, or 27 one cubic foot bags. Bagged mulch is convenient for small beds, while bulk delivery is usually cheaper above one cubic yard.
Set the depth to the internal height of the bed, then subtract any drainage layer. A 4 by 8 foot bed filled 10 inches deep needs about 27 cubic feet, or exactly one cubic yard.
Yes. Switch to metres and the inputs change to metres and centimetres, and the results are shown in square metres, cubic metres, tonnes, litre bags and 1 tonne bulk bags.
Select the circle shape and enter the diameter. The area is π multiplied by the radius squared, so a 10 foot circle covers about 78.5 square feet, or 19.6 cubic feet at 3 inches deep.
There is nothing to download: this page is the gravel calculator app and the mulch calculator app in one, running in the phone browser. Add it to your home screen from the browser menu and it opens with an icon like any other app. Every calculation, unit switch and 3D model works on a phone.
Yes for anything that will be walked on, driven over or plate-compacted. Decorative top layers need little or none, driveway layers commonly need 10 to 20 percent.
Yes for the quantities: the driveway build-up mode calculates the base, middle and top layers separately, and every calculation shows the excavated spoil to haul away, with a 25 percent swell allowance because dug soil bulks up. Falls, drainage and subgrade preparation still need planning on site.
Planning estimate only. Confirm bulk density, delivered volumes, minimum orders, sub-base requirements and drainage with your supplier or a qualified contractor before ordering or starting work.