Gravel Calculator

How much gravel to order — in cubic feet, cubic yards, tons and 0.5 cu ft bags — for a rectangle, a circle, a known square footage or a trench, in one layer or a base plus a top course. Pick a use for a typical depth and stone, with the reason and the source behind it.

The short version: cubic yards = length (ft) × width (ft) × depth (in) ÷ 324, plus 10% for clean stone or about 40% for crusher run that will be compacted. A 10 × 10 ft area at 3 inches is 1.0 yd³ of #57 — 1.4–1.4 tons.

What is it for? (optional)Picks a typical size, depth and stone, and says why. Change anything afterwards.

Shape

Length (ft)Width (ft)

Stone

Depth (in)Compaction / settling allowance (%)

Default 10% — clean, single-size stone barely compacts; the allowance covers settling, uneven subgrade and spillage. Same default as the French drain gravel calculator.

Order

1.0 cubic yards

27.5 cu ft · about 1.4–1.4 tons · or 55 bags of 0.5 cu ft · covers 100 sq ft

Show the math

Plan area: 100 sq ft
#57 stone: 100 × (3 ÷ 12) = 25 cu ft finished; × 1.1 allowance = 27.5 cu ft = 1.02 yd³ to order; 1.02 yd³ loose × 1.35–1.4 t/yd³ = 1.38–1.43 tons; 27.5 ÷ 0.5 = 55 bags

Weight basis (#57 stone): Ottr Supply lists about 1.35 tons per yd³; Knife River's #57/#67 sheet says about 1.4 tons per loose yd³, the 1.4 the site's French drain and dry well tools use.

How the calculator works

The plan area comes first: length × width, π × radius² for a circle, the square footage you enter, or for a trench its length × width. Multiply by each layer's finished depth in feet for cubic feet, divide by 27 for cubic yards, then add that layer's allowance — the extra loose stone it takes to end up at the finished depth. Bags are the ordered cubic feet ÷ 0.5, rounded up.

Weight is where stones differ. Clean stone is sold and weighed loose, so its tons are the ordered yards × its loose weight. Crusher run is different: the only measured figures we found are for the compacted base in place, so its tons are the finished yards × the compacted weight, and the allowance only changes how many loose yards to expect on the truck. That keeps the compaction from being counted twice.

Weights by stone

These ranges come from the product sheets and DOT documents listed at the bottom of the page. Moisture and rock type move them, so treat them as planning figures and check the scale ticket.

Stone	Tons per yd³	Default allowance	Good for
#57 crushed stone	1.35–1.4 (loose)	10%	Drainage trenches, dry wells, driveway top or base, under sheds
Washed drainage stone (#4–#57)	1.35–1.4 (loose)	10%	French drains, downspout trenches, dry wells, behind retaining walls
Pea gravel	1.21–1.4 (loose)	10%	Paths, play areas, patios between stepping stones, decorative beds
River rock (rounded, 1–4 in)	about 1.4 (loose)	10%	Dry creek beds, downspout outlets, borders, erosion spots
Crusher run / paver base (¾-in minus with fines)	1.8–1.86 (compacted)	40%	Driveway base, patio and paver base, shed pads, under walkways
Decomposed granite (DG)	not published	25%	Paths, patios, xeriscape borders

A note on the sources: Knife River's #57/#67 sheet gives both “approx. 1.4 tons per loose cubic yard” and a loose weight of 87 lb per cubic foot, which works out nearer 1.2 tons, so the sheet doesn't fully agree with itself. We use the stated 1.4, which matches the figure the site's French drain and dry well calculators already use, and Ottr Supply's 1.35 as the low end.

Common sizes

Computed by the same engine, with each stone's default allowance. Depths are finished depths; crusher run is compacted depth.

Job	Stone	Cu ft (finished)	Yd³ to order	Tons	0.5 cu ft bags
10 × 10 ft bed, 2 in	pea gravel	16.7	0.68	0.8–1	37
10 × 10 ft area, 3 in	#57 stone	25	1.0	1.4–1.4	55
10 × 20 ft pad, 4 in	#57 stone	66.7	2.7	3.7–3.8	147
12 × 12 ft patio base, 4 in	crusher run	48	2.5	3.2–3.3	135
12 × 24 ft driveway, 4 in	crusher run	96	5.0	6.4–6.6	269
12 × 50 ft driveway, 4 in	crusher run	200	10.4	13.3–13.8	560
20 × 20 ft pad, 4 in	#57 stone	133.3	5.4	7.3–7.6	294
3 × 30 ft path, 3 in	pea gravel	22.5	0.92	1.1–1.3	50
20 ft dry creek, 24 in wide, 6 in	river rock	20	0.82	1.1–1.1	44
50 ft French drain, 12 × 18 in	washed drainage stone	75	3.1	4.1–4.3	165

Depth and stone by use

The presets in the calculator, and where each depth comes from.

French drain trench

stone: 18 in of washed drainage stone. A typical yard French drain is 12 in wide and 18 in deep, filled with clean washed stone — the site's standard size. This figure ignores the pipe and assumes stone to the surface; the French drain gravel calculator subtracts a 4" pipe, leaves room for a topsoil cap, and adds fabric and spoil. See French drain gravel calculator · Drainage gravel sizes.

Dry creek bed

rock: 6 in of river rock. For one downspout or a small garden edge the site's dry creek guide plans a channel 18–24 in wide and 6–8 in deep, lined with rounded rock; wider and deeper (up to 3–4 ft and 12–18 in) for runoff across a lawn. We found no extension standard for rock depth, so treat this as a planning figure. See Dry creek beds.

Gravel driveway (base + top)

base course: 8 in of crusher run + surface course: 4.5 in of crusher run. Kafka Granite's spec calls for at least 8–12 in of compacted base under vehicle traffic. Penn State's dirt and gravel road program places its surface aggregate 6–8 in loose and compacts it to 4½–6 in; it specifies a dense-graded mix with fines because clean stone doesn't bind. On firm, well-drained ground an existing base may need only the surface course — change the layers to suit. See Driveway drainage.

Patio or paver base

base: 4 in of crusher run. For foot traffic Kafka Granite's spec calls for at least 4–6 in of compacted base. Paver makers set their own base and bedding-layer depths, and deeper bases on clay or wet ground — follow the install guide for your pavers. We could not open the Interlocking Concrete Pavement Institute's specification, so it isn't used here. See Patio and hardscape drainage.

Walkway or path

base: 4 in of crusher run + surface: 3 in of decomposed granite. Kafka Granite recommends at least 3 in of compacted decomposed granite over 4–6 in of compacted road base for a pedestrian path; Penn State's trail bulletin gives the same 3 in compacted (4 in loose) over a 2–6 in base. Swap the surface for pea gravel if you want a loose path.

Drainage at a downspout

stone: 6 in of washed drainage stone. Vermont's environmental agency suggests gravel at the end of a splash block to slow the water, and water draining at least 5 ft from the house. A short stone-lined channel 18 in wide and 6 in deep, carrying the water 10 ft out, matches the site's dry creek guide for one downspout. If the water needs to go further or underground, see the gutter drainage guide. See Gutter drainage · Downspout drainage problems.

Worked examples

A 12 × 50 ft driveway, 8 in base + 4½ in surface, both crusher run

600 sq ft × (12.5 ÷ 12) = 625 cu ft compacted. With the 40% compaction allowance that's about 32.4 loose cubic yards on the truck, and 41.7–43.1 tons at Wisconsin DOT's compacted weights. That's several truckloads, which is why a driveway is ordered by the ton.

A round bed 12 ft across, 3 in of pea gravel

π × 6² = 113.1 sq ft × 0.25 ft = 28.3 cu ft. With 10%, order 1.2 yd³ — 1.4–1.6 tons, or 63 bags.

Gravel and drainage

Gravel only drains when the water has somewhere to go. Stone over clay with no outlet just stores water until the clay lets it go — see does gravel help drainage? For drainage jobs, use clean washed stone with no fines; the drainage gravel sizes guide explains #57, #4, #8 and void space. For a French drain the French drain gravel calculator is the better tool: it subtracts the pipe, leaves room for a topsoil cap, and lists fabric, pipe and spoil.

On a driveway or patio, the base matters for water too: a dense, compacted base sheds water sideways, so give it a slight crown or cross-slope and somewhere to drain at the edges — see driveway drainage.

What this doesn't tell you

Whether your subgrade needs more base: soft clay, a high water table or heavy trucks call for more than these presets.
Local prices. Bulk stone is sold by the ton or the yard; ask whether the yard's figure is loose or compacted.
Edging, fabric under paths and the bedding layer under pavers, which depend on the product you use.

Frequently asked questions

How much gravel do I need?

Multiply length × width (ft) × depth (in) ÷ 12 for cubic feet, divide by 27 for cubic yards, and add an allowance for settling or compaction. A 10 × 10 ft area 3 inches deep is 25 cu ft; with 10% that's 1.0 cubic yards of #57 stone, about 1.4–1.4 tons, or 55 bags of 0.5 cu ft.

How many tons of gravel are in a cubic yard?

It depends on the stone. Clean #57 is about 1.35–1.4 tons per loose cubic yard, pea gravel 1.21–1.4, river rock about 1.4. Crusher run with its fines packs much heavier: Wisconsin DOT measured 1.8–1.86 tons per compacted cubic yard. The yard's scale ticket is the final word.

How much area does a ton of gravel cover?

At about 1.4 tons per yard, a ton of #57 is 0.71 cubic yards, which covers about 116 sq ft at 2 inches, 77 at 3 inches or 58 at 4 inches, before any allowance.

How much gravel do I need for 1,000 square feet?

At 3 inches deep, 1,000 sq ft takes 250 cu ft — 9.3 cubic yards finished, or 10.2 with a 10% allowance (13.8–14.3 tons of #57). At 2 inches it's two-thirds of that; at 4 inches, a third more.

How many bags of gravel make a cubic yard?

54 bags of 0.5 cu ft — the usual size for a 50 lb bag of stone. Bags make sense for a splash pad or a few stepping-stone gaps; past about a yard, bulk delivery is usually the easier buy.

How thick should a gravel driveway be?

Thicker than most people expect. Kafka Granite's specification calls for at least 8–12 inches of compacted base under vehicles, and Penn State's dirt and gravel road program places its surface course 6–8 inches loose to compact to 4½–6 inches. On firm, well-drained ground over an existing base, the surface course alone may do.

How much crusher run do I need for a patio or paver base?

For foot traffic, Kafka Granite's spec asks for at least 4–6 inches of compacted base. A 12 × 12 ft patio at 4 inches compacted is 48 cu ft in place; because crusher run compacts by roughly 40%, order about 2.5 loose cubic yards, about 3.2–3.3 tons. Follow your paver maker's install guide for base depth and the bedding layer.

Why does crusher run need a bigger allowance than #57?

Crusher run has fines that fill the gaps when it's compacted, so a loose yard off the truck shrinks a lot. Wisconsin DOT measured 36–47% more loose volume than compacted volume for ¾-inch dense base; Minnesota DOT's pit-gravel rule uses ×1.3. Clean #57 has no fines and barely compacts, so 10% covers settling and spillage.

What gravel is best for drainage?

Clean, washed, angular stone such as #57 — not crusher run, whose fines clog, and not pea gravel in a trench, which packs and shifts. For a French drain, use the French drain gravel calculator, which subtracts the pipe and adds the fabric and spoil.

Sources

Ottr Supply — #57 stone product page: "~2,700 lbs per cubic yard (~1.35 tons)"
Knife River, South Dakota — 3/4" x #4 (ASTM C33 #57/#67) quartzite product sheet: "Approx. 1.4 tons per loose cubic yard"
Knife River, South Dakota — 3/8" x 1/4" washed natural rock (rounded): "Approx. 1.4 tons per loose cubic yard"
GravelShop.com — #89 limestone pea gravel calculator: 2,410 lb/yd³ (1.21 t/yd³) — a figure the site uses for several stones
Knife River, South Dakota — 2"–4" washed natural rock (rounded): "Approx. 1.4 tons per loose cubic yard"
Wisconsin DOT (with Michigan State University and UW–Madison) — Research report 0092-22-05, aggregate conversion and expansion factors: ¾-in dense graded base 1.80–1.86 tons per compacted yd³, 36–47% compacted-to-loose expansion
Wisconsin DOT — Standard Specifications 305, Base Aggregate Dense: 1.85 tons per cubic yard in place
Knife River, South Dakota — 1" base course gravel: "Approx. 1.4 tons per loose cubic yard"
Minnesota DOT — Pit gravel unit conversions: loose cubic yards ÷ 1.4 = tons; loose × 1.3 = compacted
Kafka Granite — Standard Pathway specification: subbase 4–6 in compacted for pedestrians, 8–12 in for vehicles; allow 20–25% compaction of decomposed granite
Kafka Granite — Standard Pathway Mix: minimum 3 in compacted decomposed granite for pedestrian paths
Penn State Center for Dirt and Gravel Road Studies — Driving Surface Aggregate technical bulletin: 6–8 in loose, compacted to 4½–6 in
Penn State Center for Dirt and Gravel Road Studies — Trail Surface Aggregate bulletin: 4 in loose / 3 in compacted over a 2–6 in compacted base
Vermont Department of Environmental Conservation — Low Impact Development guide: gravel at the end of a splash block slows the water; drain at least 5 ft from the house
Site standards: 0.5 cu ft per bag and the #57 weight shared with the French drain gravel calculator; dry creek sizes from dry creek beds.

Every constant the site's tools use is listed on how we calculate.

French drain gravel calculator — stone, pipe, fabric and spoil for a drain trench
Topsoil & fill dirt calculator — soil in yards and tons, and fill for regrading
Mulch calculator — beds in cubic yards and bags
Drainage gravel sizes and void space — which stone for which job
Dry well calculator — size a stone-filled pit for a downspout