How do you calculate cubic yards?

Multiply length × width × depth in feet to get cubic feet, then divide by 27 (because 1 cubic yard = 27 cubic feet). For example, a slab 10 ft long × 10 ft wide × 4 inches deep = 10 × 10 × 0.333 = 33.3 cubic feet ÷ 27 = 1.23 cubic yards. This cubic yard calculator does the unit conversion and the division for you.

How many cubic feet are in a cubic yard?

There are 27 cubic feet in 1 cubic yard. A cubic yard is a cube measuring 3 ft × 3 ft × 3 ft, and 3 × 3 × 3 = 27. That is why every cubic yard calculation ends with dividing cubic feet by 27.

How much does a cubic yard weigh?

It depends entirely on the material. Approximate weights per cubic yard: concrete 4,050 lb (2.03 tons), gravel 2,835 lb (1.42 tons), sand 2,700 lb (1.35 tons), topsoil 2,100 lb (1.05 tons), and mulch 800 lb (0.4 tons). Select your material in the calculator above and it estimates tonnage automatically.

How many cubic yards of concrete do I need for a 10x10 slab?

For a 10 ft × 10 ft slab at 4 inches thick you need about 1.23 cubic yards of concrete. At 5 inches thick it is 1.54 cubic yards, and at 6 inches thick it is 1.85 cubic yards. Always order 5–10% extra for spillage and uneven subgrade — the calculator has a waste allowance field for exactly this.

How many 80 lb bags of concrete are in a cubic yard?

An 80 lb bag of pre-mixed concrete yields about 0.60 cubic feet, so you need roughly 45 bags per cubic yard. A 60 lb bag yields about 0.45 cubic feet (60 bags per yard) and a 40 lb bag yields about 0.30 cubic feet (90 bags per yard). Above roughly 1 cubic yard it is usually cheaper to order ready-mix.

How do I convert cubic yards to tons?

Multiply the cubic yards by the material density in pounds per cubic yard, then divide by 2,000. For example, 3 cubic yards of gravel at 2,835 lb/yd³ = 8,505 lb ÷ 2,000 = 4.25 US tons. The calculator shows both pounds and tons for the material you pick.

How much area does a cubic yard cover?

One cubic yard covers 324 square feet at 1 inch deep, 162 sq ft at 2 inches, 108 sq ft at 3 inches, 81 sq ft at 4 inches, 54 sq ft at 6 inches and 27 sq ft at 12 inches. Divide 324 by your depth in inches to get coverage for any thickness.

Can this cubic yard calculator handle circular and multiple areas?

Yes. Switch the shape to Circle to enter a diameter for round patios, columns or fire pits, and use the Add Area button to total several rectangles, slabs or footings in one calculation. The grand total, weight, bag count and cost all update across every area you add.

Cubic Yard Calculator — Concrete, Gravel, Dirt & Mulch Yardage

Length & width unit

Depth / thickness unit

Area 1

Length (ft)

Width (ft)

Depth (in)

Quantity

Material

Waste allowance (%)

Bag size (lb)

Price per cubic yard

Enter a length, width and depth above to see your cubic yardage.

How to Calculate Cubic Yards

The cubic yard formula

A cubic yard is a cube 3 feet on every side, so it holds 27 cubic feet. Every yardage calculation comes down to the same two steps: find the volume in cubic feet, then divide by 27.

Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27

The most common mistake is leaving depth in inches. A 4-inch slab is 4 ÷ 12 = 0.333 ft, not 4 ft. The calculator above handles that conversion for you, so you can enter depth in inches and length in feet without converting anything by hand.

Worked example: a 10 × 10 concrete slab

Area = 10 ft × 10 ft = 100 sq ft
Depth = 4 in ÷ 12 = 0.333 ft
Volume = 100 × 0.333 = 33.3 cubic feet
Cubic yards = 33.3 ÷ 27 = 1.23 cubic yards
With a 10% waste allowance = 1.36 yd³ → order 1.5 yd³

Round areas and columns

For a circular patio, fire pit or footing, the area is π × radius², where the radius is half the diameter. A 12 ft round patio at 4 inches deep works out to 3.14 × 6² = 113 sq ft × 0.333 ft = 37.7 cubic feet = 1.4 cubic yards. Switch the shape toggle to Circle and enter the diameter — the calculator applies the formula automatically.

Coverage per cubic yard by depth

Depth	Coverage of 1 cubic yard
1 inch	324 sq ft
2 inches	162 sq ft
3 inches	108 sq ft
4 inches	81 sq ft
6 inches	54 sq ft
12 inches	27 sq ft

Weight of a cubic yard by material

Material	lb per yd³	US tons per yd³
Concrete (ready-mix)	4,050	2.02
Gravel / crushed stone	2,835	1.42
Sand	2,700	1.35
Topsoil	2,100	1.05
Mulch (bark)	800	0.40
Compost	1,100	0.55
Asphalt	3,960	1.98
Limestone (crushed)	2,565	1.28

These are typical dry densities. Wet sand, gravel and topsoil can be 10–20% heavier, which matters when you are checking a truck's payload limit.

Bags vs ready-mix

An 80 lb bag of concrete mix yields about 0.60 ft³, so a single cubic yard takes roughly 45 bags. Below about half a cubic yard, bags are usually cheaper and far more convenient. Above one cubic yard, ordering ready-mix is normally cheaper per yard and guarantees a consistent pour — most suppliers have a minimum order of 1 yard and charge a short-load fee under 3–4 yards.

Cubic Yard Calculator