Gravel Calculator
Find how much gravel, stone, sand, topsoil or mulch to order for a path, driveway or garden bed: volume, weight, bags, truck loads and cost.
Typical gravel: about 1.42 tons per cu yd (1.68 t per m³).
Length and width above are the bed, patio or house the strip goes round.
Mulch and decorative stone 2–3 in (5–8 cm); driveways 4–6 in (10–15 cm).
Length and width above are the bed, patio or house the strip goes round.
Length and width above are the bed, patio or house the strip goes round.
Length and width above are the bed, patio or house the strip goes round.
5–10% is usual; more on uneven ground.
Crushed stone and road base settle when rolled or driven on; some suppliers suggest 10–15%.
Changes to the usual bag for the material until you pick one yourself.
Dump trucks often carry 10–15 tons; small trucks about 5. A pickup's payload is often 1 ton or less. Ask your supplier.
How your gravel is worked out
Area × depth = volume, plus a little extra, then × how much it weighs.
- 1
Find the area
10 × 10 ft= 100 sq ft
- 2
Times the depth
3 in = 0.25 ft100 × 0.25= 25 cu ft
- 3
Add 5% extra
25 × 1.05= 26.25 cu ft= 0.97 cu yd
- 4
Weigh it
0.972 cu yd× 1.42 tons each= 1.38 tons
Read more: the formulas for every shape, a worked example, typical weights and depths
Gravel, stone, sand, soil and mulch are sold by volume (cubic yards or cubic metres), by weight (tons or tonnes) or by the bag. So the job is to find the area, multiply by the depth to get the volume, add a little extra, then turn that into weight, bags or truck loads.
The formula
rectangle = length × width
circle = π × (diameter ÷ 2)²
triangle (sides a, b, c) = √(s × (s − a) × (s − b) × (s − c)), where s = (a + b + c) ÷ 2
ring = π ÷ 4 × (outside diameter² − inside diameter²)
border strip = (length + 2 × strip width) × (width + 2 × strip width) − length × width
volume = area × depth (each area with its own depth, then added up)
to order = volume × (1 + (waste % + packing-down %) ÷ 100)
weight = volume to order × density
bags = volume to order ÷ what one bag holds (or weight ÷ bag weight), rounded up
truck loads = weight (or volume) ÷ what one load holds, rounded up
cubic yards = cubic feet ÷ 27 · 1 US ton = 2,000 lb · 1 tonne = 1,000 kg
Worked example
A gravel patch 10 ft long, 10 ft wide and 3 in deep. The area is 10 × 10 = 100 sq ft. 3 in is 3 ÷ 12 = 0.25 ft, so the volume is 100 × 0.25 = 25 cu ft. Adding 5% extra gives 25 × 1.05 = 26.25 cu ft, which is 26.25 ÷ 27 = 0.972 cu yd (0.743 m³). Gravel weighs about 1.42 tons per cu yd (1,680 kg per m³), so it weighs 0.7433 × 1,680 = 1,249 kg, which is 1.38 US tons (1.25 tonnes). In 0.5 cu ft bags that is 26.25 ÷ 0.5 = 52.5, rounded up to 53 bags. One 10-ton truck load is plenty.
Typical weights
| Material | Tons per cu yd | Tonnes per m³ | Usual bag |
|---|---|---|---|
| Gravel (mixed gravel, dry) | 1.42 | 1.68 | 0.5 cu ft |
| Crushed stone (crushed rock, ¾ in (20 mm)) | 1.35 | 1.6 | 0.5 cu ft |
| Pea gravel (small round stones) | 1.28 | 1.52 | 0.5 cu ft |
| River rock (round stones, 1–3 in) | 1.35 | 1.6 | 0.5 cu ft |
| Road base (crusher run, MOT type 1; packs hard) | 1.62 | 1.92 | 0.5 cu ft |
| Decomposed granite (fine crushed granite) | 1.28 | 1.52 | 0.5 cu ft |
| Sand (dry; damp sand is heavier) | 1.35 | 1.6 | 50 lb |
| Topsoil (dry; wet soil is heavier) | 1.08 | 1.28 | 0.75 cu ft |
| Mulch (wood chips or bark) | 0.34 | 0.4 | 2 cu ft |
| Lava rock (light, porous stone) | 0.54 | 0.64 | 0.5 cu ft |
These are typical loose, dry weights used as rules of thumb. Real loads vary a lot: wet sand and soil can weigh a quarter more, and stone size and shape change how tightly it packs. Your supplier's own figure is always best; pick "My own density" in Advanced to use it.
How deep to spread it
| Job | Usual depth | 1 cu yd covers |
|---|---|---|
| Mulch on beds | 2–3 in (5–8 cm) | 162–108 sq ft |
| Decorative stone, pea gravel paths | 2–3 in (5–8 cm) | 162–108 sq ft |
| Sand under pavers | 1 in (2.5 cm) | 324 sq ft |
| Topsoil for a new lawn | 4–6 in (10–15 cm) | 81–54 sq ft |
| Gravel driveway (in layers) | 4–6 in (10–15 cm) or more | 81–54 sq ft |
Depths are common rules of thumb, not building rules. 1 cu yd covers 324 ÷ depth in inches square feet; 1 m³ covers 100 ÷ depth in cm square metres.
Tips for ordering
- Under about 1 cu yd (0.75 m³), bags are often easier. Above that, bulk delivery is usually cheaper, but check the minimum order and delivery fee.
- Suppliers price by the ton in some places and by the cubic yard or m³ in others. The cost box takes any of them and works out the rest.
- For a driveway, lay crushed stone or road base in layers and roll each one. Add a packing-down extra so you don't run short.
Common questions
How do I calculate how much gravel I need?
Work out the area, multiply by the depth and add a little extra. A patch 10 ft by 10 ft is 100 sq ft. At 3 in deep (0.25 ft) that is 25 cu ft. Add 5% extra to get 26.25 cu ft, then divide by 27 for cubic yards: 0.97 cu yd, or 0.74 m³.
How many tons of gravel are in a cubic yard?
Typical gravel weighs about 1.42 US tons per cubic yard (1.68 tonnes per m³). Crushed stone and sand are about 1.35, pea gravel 1.28, road base 1.62, topsoil 1.08 and wood mulch only 0.34. Wet material weighs more, so ask your supplier for the figure they use.
How many bags of gravel or mulch do I need?
Divide the volume you are ordering by what one bag holds and round up. 26.25 cu ft of gravel in 0.5 cu ft bags is 52.5, so 53 bags. Mulch usually comes in 2 cu ft bags, so the same 26.25 cu ft would be 13.1, rounded up to 14 bags.
How much area does a cubic yard cover?
A cubic yard is 27 cu ft, so it covers 324 ÷ depth in inches square feet. At 2 in deep that is 162 sq ft, at 3 in 108 sq ft and at 4 in 81 sq ft. In metric, 1 m³ covers 10 m² at 10 cm deep, or 20 m² at 5 cm.
How deep should gravel or mulch be?
As a rule of thumb, mulch and decorative stone are spread 2–3 in (5–8 cm) deep, and garden paths 2–3 in of gravel over a firm base. Driveways usually take 4–6 in (10–15 cm) or more, laid in layers with a road base underneath. Sand under pavers is about 1 in (2.5 cm).
How much extra gravel should I order?
The calculator adds 5% for spills and uneven ground. Crushed stone and road base also pack down when rolled or driven on, so in Advanced you can add a separate extra for that; some suppliers suggest 10–15%. Both extras are added before bags, weight, truck loads and cost are worked out.
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