Cubic Yard Calculator: How Many Yards Do You Need?
Use this free cubic yard calculator to find the volume of a slab, footing, wall, column or any box-shaped space in cubic yards. For concrete, it also shows how many 40, 50, 60 and 80 lb bags you need and what the pour weighs. Add a section for each part of your project and they are totaled for you, so it works as a concrete calculator in yards and as a general yardage calculator for soil, mulch and gravel.
Estimates only · 1 cubic yard = 27 ft³ · Last updated November 10, 2026
Cubic Yard and Concrete Volume Calculator
Advanced Options (Material Density & Weight)▼
1.48 yd³ exact + 10% waste factor
| Volume Unit | Exact | With Waste |
|---|---|---|
| Cubic Yards (yd³) | 1.48 | 1.63 |
| Cubic Feet (ft³) | 40.0 | 44.0 |
| Cubic Meters (m³) | 1.13 | 1.25 |
*Typical yields — check the yield printed on your bag.
| Weight Unit | Exact | With Waste |
|---|---|---|
| Pounds (lb) | 6,000 | 6,600 |
| US Short Tons | 3.00 | 3.30 |
| Metric Tonnes | 2.72 | 2.99 |
Show calculation steps▾
- Patio: 40.0 ft³ (1.48 yd³)
- Total exact volume: 40.0 ft³ ÷ 27 = 1.48 yd³
- Order volume (+10% waste): 44.0 ft³ ÷ 27 = 1.63 yd³
- 80 lb bags: 44.0 ft³ ÷ 0.60 ft³/bag = 73.3 → 74 bags
- Weight: 44.0 ft³ × 150 lb/ft³ = 6,600 lb (3.30 tons)
Estimate only. Does not include price, delivery, rebar, forms or base material.
Results are planning estimates. Check your bag label for its yield and ask your ready-mix supplier about minimum loads before you order.
How to Calculate Cubic Yards (Formula and Examples)
Calculating cubic yards takes three steps: find the volume in cubic feet, divide by 27, then add extra for waste. The same method works for concrete, soil, mulch and gravel.
The cubic yard formula
- Convert every measurement to feet (inches ÷ 12).
- Volume (ft³) = length × width × depth.
- Cubic yards = cubic feet ÷ 27.
- Order quantity = cubic yards × (1 + waste %).
Shortcut for a slab: cubic yards = length (ft) × width (ft) × thickness (in) ÷ 324.
Worked example: 10 × 12 ft patio, 4 in thick (how to estimate concrete yards)
- Volume: 10 × 12 × (4 ÷ 12) = 40 ft³
- Cubic yards: 40 ÷ 27 = 1.48 yd³
- Add 10% waste: 1.48 × 1.10 = 1.63 yd³ (44 ft³)
- To order: about 1.75 yd³ of ready-mix (rounded up to the next quarter yard), or 74 bags of 80 lb mix (44 ÷ 0.60 = 73.3, rounded up)
- Weight: about 6,000 lb (3 tons) before waste
Figuring yards of concrete by shape
The formulas below use feet. Convert inches to feet by dividing by 12.
| Shape | Formula | Example |
|---|---|---|
| Slab, patio or driveway | length × width × thickness ÷ 27 | 10 × 12 ft, 4 in thick → 1.48 yd³ |
| Footing or trench | run length × width × depth ÷ 27 | 100 ft, 16 in wide, 8 in deep → 3.29 yd³ |
| Wall | length × height × thickness ÷ 27 | 20 ft long, 4 ft high, 8 in thick → 1.98 yd³ |
| Round column, pier or post hole | π × (diameter ÷ 2)² × height ÷ 27 | 4 columns, 12 in across, 4 ft tall → 0.47 yd³ |
How Much Is a Yard of Concrete?
A yard of concrete means one cubic yard: a volume of 3 ft × 3 ft × 3 ft, or 27 cubic feet. At the usual density of 150 lb/ft³ it weighs about 4,050 lb, a little over 2 tons. You can mix it from roughly 45 bags of 80 lb mix, or order it from a ready-mix plant by the yard.
People also ask this as a price question. Ready-mix is sold per cubic yard plus delivery, and what you pay depends on your region, the mix strength, the season and whether your order counts as a small load. Call two or three local suppliers for current prices, or use our [Concrete Slab Cost Calculator] to turn your yards into a budget.
How much does a yard of concrete weigh?
About 4,050 lb (1,837 kg) for normal-weight concrete at 150 lb/ft³. The exact figure shifts a little with the mix design, aggregate and moisture, and reinforcing steel adds more.
How much is a cubic yard?
A cubic yard is a unit of volume. These are the conversions you will use most:
| 1 cubic yard equals | Value |
|---|---|
| Cubic feet | 27 ft³ |
| Cubic inches | 46,656 in³ |
| Cubic meters | 0.7646 m³ |
| Liters | about 764.6 L |
| US gallons | about 202 gal |
Going the other way, 1 cubic meter is about 1.308 cubic yards.
How Many Bags of Concrete Do I Need?
Bagged mix is sold by weight, but the number of bags you need depends on yield, the amount of mixed concrete one bag makes. Typical yields are below. Always confirm the yield printed on your bag, because it varies by product.
| Bag size | Typical yield per bag | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 ft³ (0.011 yd³) | 90 |
| 50 lb | 0.375 ft³ (0.014 yd³) | 72 |
| 60 lb | 0.45 ft³ (0.017 yd³) | 60 |
| 80 lb | 0.60 ft³ (0.022 yd³) | 45 |
Bags needed = cubic feet ÷ yield per bag, rounded up. Add your waste percentage to the volume first. Bags work well for small jobs, but 45 bags per yard is about 3,600 lb of dry mix to lift and mix, which is why larger pours usually go to a ready-mix truck.
Cubic Yards of Concrete for Common Slab Sizes
Planning figures before waste. Add 5–10% when you order.
| Slab size | 4 in thick | 6 in thick |
|---|---|---|
| 10 × 10 ft | 1.23 yd³ | 1.85 yd³ |
| 12 × 12 ft | 1.78 yd³ | 2.67 yd³ |
| 10 × 20 ft | 2.47 yd³ | 3.70 yd³ |
| 20 × 20 ft | 4.94 yd³ | 7.41 yd³ |
| 24 × 24 ft | 7.11 yd³ | 10.67 yd³ |
Rule of thumb: one cubic yard covers about 108 sq ft at 3 inches thick, 81 sq ft at 4 inches, and 54 sq ft at 6 inches. Patios and sidewalks are commonly poured about 4 inches thick, and driveways and garage floors about 4–6 inches. Your local code, soil and loads decide the real specification.
Concrete Footing Calculator
A continuous (strip) footing is a long, narrow box. Choose Footing / trench, enter the total run as the length, then the footing width and depth. Use Add section for separate wall lines or footings of different sizes.
Example: a 100 ft run that is 16 in wide and 8 in deep: 100 × (16 ÷ 12) × (8 ÷ 12) = 88.9 ft³ = 3.29 yd³, or about 3.6 yd³ with 10% waste.
Footing size is not a guess. Width, depth, steel and frost depth depend on your soil, loads and local building code, so confirm them with your building department or an engineer before you pour. This tool only turns your dimensions into volume.
For piers, post holes and tube forms, choose Column / round hole. A post hole 10 in across and 30 in deep holds 1.36 ft³, about 0.05 yd³, or roughly 3 bags of 80 lb mix. The post itself takes up space, so you will use a little less.
Bags or Ready-Mix?
- Under about 1 cubic yard: bagged mix is usually the practical choice.
- Roughly 1 to 5 cubic yards: compare both. Ready-mix saves labor, but many suppliers charge extra for small loads, so ask about minimum orders and short-load fees.
- Over about 5 cubic yards: ready-mix delivery is usually the practical choice. A full mixer truck commonly holds around 8 to 10 cubic yards.
Ready-mix is often ordered in quarter-yard steps, so the calculator shows a suggested quantity rounded up to the next ¼ yard. Confirm the details with your supplier.
Yardage Calculator for Soil, Mulch and Gravel
The same math gives the yardage for any bulk material. Switch Material to Other, enter your dimensions, and the result is cubic yards with no bag counts. Bulk soil, mulch and gravel are usually sold by the cubic yard, but some suppliers sell by the ton, and cubic yards only convert to tons when you know the density of that exact material.
For materials with their own calculators, use these:
Tips Before You Order
- Measure twice. Check thickness in several places, because subgrade is rarely perfectly flat.
- Add 5–10% extra. The calculator starts at 10% for concrete and 5% for other materials.
- Check the bag label. Yield differs between products.
- Be ready when the truck arrives. Have forms, base and helpers in place before delivery, because waiting time may cost extra.
- Add every part of the job. Thickened edges, footings and steps need their own sections.
Frequently Asked Questions
How do you calculate cubic yards?
Multiply length × width × depth in feet to get cubic feet, then divide by 27. For a slab you can use length (ft) × width (ft) × thickness (in) ÷ 324.
How many cubic yards is a 10 × 10 slab that is 4 inches thick?
About 1.23 cubic yards, or about 1.36 yd³ with 10% waste added.
How many bags of concrete make a yard?
About 45 bags of 80 lb mix, 60 bags of 60 lb mix, 72 bags of 50 lb mix, or 90 bags of 40 lb mix, based on typical yields.
How much does a cubic yard of concrete weigh?
About 4,050 lb, or roughly 2 tons, for normal-weight concrete at 150 lb/ft³.
How many cubic feet are in a cubic yard, and how do I convert?
There are 27 cubic feet in a cubic yard. Divide cubic feet by 27 to get cubic yards. For example, 100 ft³ ÷ 27 = 3.70 yd³.
How do I calculate concrete yards for a footing?
Multiply the total footing length by its width and depth (all in feet), then divide by 27. A 100 ft run that is 16 in wide and 8 in deep needs about 3.29 yd³. Ask your building department or an engineer for the required footing size.
How much extra concrete should I order?
Most people add 5–10% for uneven subgrade, spillage and over-excavation. The calculator uses 10% for concrete by default, and you can change it.
Is it cheaper to use bags or ready-mix?
For small jobs, bags are usually easier. As the volume grows, ready-mix usually becomes the better choice, because 45 bags per yard means a lot of lifting and mixing. Compare current local prices, delivery fees and short-load fees before you decide.
How many square feet does a cubic yard of concrete cover?
About 81 square feet at 4 inches thick and about 54 square feet at 6 inches thick.
Can I use this calculator for soil, mulch or gravel?
Yes. Switch Material to Other to get cubic yards without bag counts. To find the weight, enter your material's density in the advanced options.
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About These Estimates
KKCTools calculators use standard unit conversions and commonly used planning figures. Results are estimates for planning and ordering. They are not engineering, structural or building-code advice. Always confirm quantities, bag yields, footing sizes and delivery terms with your supplier, building department or a qualified professional. Last updated November 10, 2026.