Mulch, soil and gravel calculator

Enter the bed's shape, size and depth. See the cubic yards to order, how many bags of each size that is, and roughly what it weighs, for mulch, topsoil, gravel, crushed stone, sand or river rock.

27 cu ftIn one cubic yard

108 sq ftOne yard covers at 3 in

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Mulch needed

2.04 cu yd

55 cu ft, 28 bags of 2 cu ft, about 0.83 tons

200 sq ftArea

55Cubic feet

28Bags of 2 cu ft

0.83 tonsWeight

Free. Your numbers become an estimate you can send from your phone.

How we got this

Area20 × 10 = 200 sq ft
Volume200 sq ft × 3 in ÷ 12 = 50 cu ft
Extra+ 10% = 55 cu ftLoose material settles. Most yards round up to the next half or whole yard anyway.
Cubic yards55 ÷ 27 = 2.04 cu ydA cubic yard is 3 ft × 3 ft × 3 ft, 27 cu ft.
Weight55 cu ft × 30 lb = 1,650 lb, 0.83 tonsLoose, dry density for mulch from a bulk supplier's published reference. Wet material weighs more. Yards that sell by the ton weigh the truck, so the ticket can differ.
Bags55 ÷ 2 cu ft = 28 bagsRounded up. Typical depth for mulch: 3 in on a new bed, 1.5 to 2 in to refresh one.

Bag size	Bags needed	Bags in one cubic yard
0.5 cu ft	110	54
0.75 cu ft	74	36
1 cu ft	55	27
1.5 cu ft	37	18
2 cu ft	28	13.5
3 cu ft	19	9

Sources: Aggregate Markets, Bulk material calculators and density reference; Grass Roots landscape supply (Marshfield, MO), How much mulch, topsoil or rock do I need. Checked 2026-10-08.

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Key takeaways

Cubic yards = length × width (ft) × depth (in) ÷ 12 ÷ 27. A 10 × 10 ft bed 3 in deep takes 0.93 cubic yards.
One cubic yard covers 324 sq ft at 1 in deep, 162 at 2 in and 108 at 3 in. Divide 324 by the depth in inches.
Bags: divide the cubic feet by the bag size. A yard is 13.5 bags of 2 cu ft or 9 bags of 3 cu ft.
Gravel, crushed stone and sand weigh about 1.35 tons a yard loose and dry, topsoil about 1.05 and mulch about 0.4.

How to work out cubic yards of mulch, soil or gravel

Every bulk material is sold by volume or by weight, and both start with the same number: the volume of the bed.

Area. Length × width in feet for a rectangle. For a round bed, 0.785 × diameter². For a triangle, half of base × height. Add the beds up if there are several.
Volume in cubic feet. Area × depth in inches ÷ 12.
Cubic yards. Cubic feet ÷ 27, since a cubic yard is 3 ft × 3 ft × 3 ft.
Extra. Add 5% to 10% for settling and for the edges that always take more than you think.

In one line: cubic yards = length × width × depth in inches ÷ 324. The 324 is 12 inches × 27 cubic feet.

A bulk supplier's own calculator gives the same answer for its example: a 10 × 10 ft area at 3 in deep is 100 × 0.25 = 25 cu ft, which is 0.93 cubic yards. This calculator matches it to the hundredth.

Depth	One cubic yard covers	Cubic yards per 100 sq ft	Cubic yards per 1,000 sq ft
1 in	324 sq ft	0.31	3.09
2 in	162 sq ft	0.62	6.17
3 in	108 sq ft	0.93	9.26
4 in	81 sq ft	1.23	12.35
6 in	54 sq ft	1.85	18.52

These are before any extra for settling. Round up to what the yard sells: most sell by the whole or half yard.

How many bags of mulch or soil you need

Bagged mulch, soil and stone are sold by the cubic foot printed on the bag, not by weight. Divide the cubic feet you need by the bag size and round up.

Bag size	Bags in one cubic yard	Bags for 100 sq ft at 2 in	Bags for 100 sq ft at 3 in
0.5 cu ft	54	34	50
0.75 cu ft	36	23	34
1 cu ft	27	17	25
1.5 cu ft	18	12	17
2 cu ft	13.5	9	13
3 cu ft	9	6	9

100 sq ft at 2 in is 16.7 cu ft; at 3 in it is 25 cu ft. The bag columns are those figures divided by the bag size and rounded up.

Bags make sense for small beds and touch-ups. Past a yard or two, bulk is usually less work to buy: one loader scoop is a cubic yard, the same as 13.5 bags of 2 cu ft, with no plastic to throw away. The calculator shows the bag count for every common size so you can compare it with the bulk price.

How much a yard of gravel, soil or mulch weighs

Stone and sand are often sold by the ton, and weight decides how much a pickup or trailer can safely carry. Tons = cubic feet × weight per cubic foot ÷ 2,000.

Material	Loose, dry weight	Tons per cubic yard	Cubic yards per ton
Mulch	30 lb per cu ft	0.41	2.47
Topsoil	78 lb per cu ft	1.05	0.95
Gravel	100 lb per cu ft	1.35	0.74
Crushed stone	100 lb per cu ft	1.35	0.74
Sand	100 lb per cu ft	1.35	0.74
River rock	103 lb per cu ft	1.39	0.72

The weights are the typical loose, dry densities a bulk aggregate supplier publishes. Real loads vary with moisture, grain size and the quarry: wet sand and soil weigh noticeably more, and a yard that sells by the ton weighs your truck on its scale. Treat the tons as a planning figure and ask the yard how it sells.

Weight matters most when you haul it yourself. A cubic yard of gravel is about 2,700 lb, which is more than the payload of many half-ton pickups. A landscape yard in Missouri tells its customers to expect a light duty truck to carry one cubic yard and a heavy duty truck about two.

How deep to spread mulch, soil and rock

Depth drives the whole order, so pick it before you measure. These are the depths a landscape supply yard gives its own customers, and the calculator's defaults follow them:

Mulch on a new bed: about 3 in. Keep it pulled back a little from stems and trunks.
Refreshing existing mulch: 1.5 to 2 in on top of what is there.
Decorative rock: 2 to 4 in, deeper for bigger stones, so no weed fabric shows between them.
River rock and large garden stone: about 4 in, because round stones leave bigger gaps.
Compost on an existing lawn: about 3/4 in, worked in and watered.

Bulk yards sell in their own steps, so round the answer up to what they sell. If the calculator says 2.04 yards, ask whether the yard will load a quarter or half yard extra, or order 2 and keep a few bags on hand for the corners. Running short on a delivery is worse than a little left over, since a second trip often costs a second delivery fee.

For base layers under a patio, walk or driveway, follow the paver or slab maker's spec for depth and compaction. Compacted stone takes more material than its loose depth suggests, so add more extra, not less.

Measure the real depthPush a ruler into an existing bed in a few places before you refresh it. Beds that look bare often still have an inch or more of old mulch, and topping up to 3 in on top of that wastes material.

Worked examples

A front bed in mulch. 20 ft by 10 ft at 3 in, plus 10% for settling. 200 sq ft × 3 ÷ 12 = 50 cu ft, plus 10% is 55 cu ft. 55 ÷ 27 = 2.04 cubic yards, so order 2 yards bulk, or 28 bags of 2 cu ft. At 30 lb per cu ft, that is about 1,650 lb.

Three tree rings. Three rings 8 ft across, 2 in of mulch, no extra. Each ring is 0.785 × 64 = 50.3 sq ft, so 150.8 sq ft in all. × 2 ÷ 12 = 25.1 cu ft, 0.93 cubic yards, or 9 bags of 3 cu ft.

Topsoil to level a lawn area. 500 sq ft at 4 in. 500 × 4 ÷ 12 = 166.7 cu ft, which is 6.17 cubic yards. At 78 lb per cu ft, about 6.5 tons. That is a dump truck delivery, not a pickup run.

Gravel for a side yard path. 10 ft by 10 ft at 3 in: 25 cu ft, 0.93 yards, about 1.25 tons, or 50 bags of 0.5 cu ft.

A triangle corner of sand. A corner 12 ft along one side and 9 ft along the other, 12 in deep: half of 12 × 9 is 54 sq ft, × 1 ft = 54 cu ft, exactly 2 cubic yards.

Pricing a mulch or rock job

For a landscaper, the material is the easy part of the quote. The calculator puts the cubic yards and the square feet into two lines you can save as an estimate, so you only add your own prices:

Material by the yard at what your supplier charges you, plus your markup.
Delivery if the supplier charges it, or your truck time if you haul it.
Labor by the square foot or by the hour. Spreading by hand is slower around plants and edging than across open ground. Track how long your own crew takes per yard and use that.
Prep: weeding, edging, removing old rock, laying fabric. Price these as their own lines so the customer sees them.

To check that the price still makes money, run it through the markup calculator. For recurring work, the lawn care cost calculator covers mowing and seasonal visits. When the numbers are right, send the estimate from Koira.

Last checked October 8, 2026. More for your trade: how lawn and landscape crews run on Koira.

FAQ

How many cubic yards of mulch do I need?

Multiply length by width in feet, multiply by the depth in inches, and divide by 324. A 20 × 10 ft bed at 3 in is 200 × 3 ÷ 324 = 1.85 cubic yards, or about 2.04 with 10% extra for settling.

How many square feet does a yard of mulch cover?

324 divided by the depth in inches. At 3 in a cubic yard covers 108 sq ft, at 2 in 162 sq ft, and at 4 in 81 sq ft.

How many bags of mulch are in a yard?

A cubic yard is 27 cubic feet, so it is 13.5 bags of 2 cu ft, 9 bags of 3 cu ft, or 18 bags of 1.5 cu ft.

How much does a yard of gravel weigh?

Loose, dry gravel, crushed stone and sand run about 100 lb per cubic foot, which is about 2,700 lb or 1.35 tons a cubic yard. Wet material weighs more, and stone from different quarries varies.

How many tons of gravel do I need?

Work out the cubic yards first, then multiply by about 1.35 tons a yard for gravel or crushed stone. A 10 × 10 ft area at 3 in is 0.93 yards, about 1.25 tons.

How deep should mulch be?

About 3 in on a new bed, and 1.5 to 2 in when refreshing an old one. Check how much old mulch is still there before topping up.

How much does a yard of topsoil weigh?

About 78 lb per cubic foot loose and dry, roughly 2,100 lb or 1.05 tons a cubic yard. Moist topsoil weighs more.

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