🧱 Cubic Yard Calculator for Concrete, Dirt, Gravel and Mulch
By Shihab Mia · Updated 2026-07-06
Enter the length, width and depth of the area. Volume in cubic feet is length x width x depth (all in feet), then divided by 27 to get cubic yards. Add a waste allowance of 5 to 10 percent when ordering.
A cubic yard calculator turns the length, width and depth of your project into the number of cubic yards you need to order for concrete, dirt, gravel, sand or mulch. The core math is simple: multiply length x width x depth in feet to get cubic feet, then divide by 27, since one cubic yard equals 27 cubic feet. Enter each measurement in feet, inches or meters, set how many identical areas you have, and read off the cubic yards, cubic meters, cubic feet, bag counts and an optional cost from a price per cubic yard.
What is the Cubic Yard Calculator?
A cubic yard is the volume of a cube that measures one yard (3 feet) on every side. Because 3 x 3 x 3 = 27, one cubic yard equals 27 cubic feet. That single conversion is the heart of every yardage calculation: work out the volume of your area in cubic feet, then divide by 27 to get cubic yards. The volume in cubic feet is simply length x width x depth, with all three measurements expressed in feet.
The part that trips most people up is the depth. Slabs, driveways, garden beds and gravel layers are usually only a few inches deep, not feet, so the depth has to be converted before it goes into the formula. Four inches is 4 divided by 12, or 0.3333 feet, not 4 feet. This calculator lets you pick the unit for each dimension separately, so you can leave length and width in feet and enter the depth in inches without doing the conversion by hand. A handy shortcut for a rectangle when depth is in inches is (length ft x width ft x depth in) divided by 324, because 324 combines the inches-to-feet step (divide by 12) and the cubic-feet-to-cubic-yards step (divide by 27) into one number.
Not every project is a neat rectangle. For a round pad, footing or pillar, the area is pi x radius squared, so cubic yards = (3.14159 x radius ft x radius ft x depth ft) divided by 27, where the radius is half the diameter. For a triangular area, use half the base times the height for the area, then multiply by depth and divide by 27. Irregular shapes are easiest to handle by splitting the plan into rectangles, circles and triangles, calculating each piece, and adding the results together.
Materials are ordered by volume, but they behave differently once delivered. Concrete is a liquid that fills the form exactly, so the calculated cubic yards is what you pour. Loose materials like soil, mulch and gravel settle and compact, and there is always spillage and uneven ground, so contractors typically add a waste allowance of 5 to 10 percent for soil and mulch and 10 to 15 percent for gravel and compacted base. Concrete in particular is hard to top up once a pour starts, so rounding up to the next quarter yard is common practice.
Weight matters as much as volume when you plan delivery and check whether your vehicle or trailer can carry a load. A cubic yard of poured concrete weighs roughly 4,000 pounds (about 2 tons), dry topsoil around 2,000 pounds, gravel about 2,800 pounds, and mulch a much lighter 400 to 800 pounds depending on moisture. Most ready-mix trucks hold up to about 10 cubic yards, and many suppliers charge a short-load fee for orders under a full truck, so it can pay to round a small order up to a delivery-friendly size.
If you are buying bagged concrete instead of ready-mix, remember that one cubic yard takes about 45 bags of 80 lb mix, 60 bags of 60 lb mix, or 90 bags of 40 lb mix. Bagged concrete makes sense for small repairs and footings, but for anything approaching a full yard the labor of mixing dozens of bags usually makes a ready-mix delivery cheaper and easier.
When to use it
- Working out how many cubic yards of ready-mix concrete to order for a slab, footing, patio or driveway.
- Estimating cubic yards of topsoil, compost or fill dirt for a garden bed, lawn or landscaping project.
- Calculating gravel, sand or road base for a base layer, path, patio or drainage trench.
- Figuring out how much mulch or bark to buy to cover flower beds to a set depth.
- Converting a square-foot area and a depth into cubic yards for a delivery quote.
- Deciding between bagged concrete and a ready-mix truck by comparing bag counts against yardage.
How to use the Cubic Yard Calculator
- Enter the length of the area and choose its unit (feet, inches or meters).
- Enter the width and its unit the same way.
- Enter the depth or thickness, then pick the unit (inches is common for slabs and layers).
- Set the number of identical areas if you have more than one, and optionally a price per cubic yard.
- Read off the cubic yards, cubic meters and cubic feet, plus the estimated cost.
- Add a waste allowance (5 to 15 percent) and round up to a sensible order size before you buy.
Formula & method
Worked examples
A concrete slab 10 ft long, 10 ft wide and 4 inches thick.
- Convert depth to feet: 4 / 12 = 0.3333 ft
- Cubic feet = 10 x 10 x 0.3333 = 33.33 ft3
- Cubic yards = 33.33 / 27 = 1.23 yd3
- Cubic meters = 33.33 x 0.0283168 = 0.94 m3
- Shortcut check: (10 x 10 x 4) / 324 = 1.23 yd3
Result: 1.23 cubic yards (about 0.94 cubic meters). Order 1.25 to 1.5 yards to allow for waste. That is roughly 56 bags of 80 lb concrete if you bag it.
A garden bed 20 ft long, 4 ft wide, filled with 6 inches of topsoil.
- Convert depth to feet: 6 / 12 = 0.5 ft
- Cubic feet = 20 x 4 x 0.5 = 40 ft3
- Cubic yards = 40 / 27 = 1.48 yd3
- Add 10 percent for settling: 1.48 x 1.10 = 1.63 yd3
Result: 1.48 cubic yards of soil, or about 1.63 cubic yards once a 10 percent allowance is added.
A round concrete pad 8 ft across (diameter), 4 inches thick.
- Radius = diameter / 2 = 8 / 2 = 4 ft
- Convert depth to feet: 4 / 12 = 0.3333 ft
- Cubic feet = 3.14159 x 4 x 4 x 0.3333 = 16.76 ft3
- Cubic yards = 16.76 / 27 = 0.62 yd3
Result: About 0.62 cubic yards. Round up to 0.75 yards, or plan on roughly 28 bags of 80 lb concrete for a bagged pour.
Cubic yards needed to cover an area at common depths (length x width in square feet)
| Area (sq ft) | 2 in deep | 4 in deep | 6 in deep | 12 in deep |
|---|---|---|---|---|
| 100 | 0.62 yd3 | 1.23 yd3 | 1.85 yd3 | 3.70 yd3 |
| 200 | 1.23 yd3 | 2.47 yd3 | 3.70 yd3 | 7.41 yd3 |
| 500 | 3.09 yd3 | 6.17 yd3 | 9.26 yd3 | 18.52 yd3 |
| 1000 | 6.17 yd3 | 12.35 yd3 | 18.52 yd3 | 37.04 yd3 |
How much area one cubic yard covers at a given depth
| Depth | Coverage from 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 |
Approximate weight and bag counts per cubic yard (varies with moisture and mix)
| Material | Weight per yd3 | Notes |
|---|---|---|
| Concrete (poured) | ~4,000 lb (2 tons) | About 45 x 80 lb bags, 60 x 60 lb bags, 90 x 40 lb bags |
| Topsoil (dry) | ~2,000 lb (1 ton) | Heavier when wet; add 5 to 10 percent for settling |
| Gravel / stone | ~2,600 to 3,000 lb | Add 10 to 15 percent for a compacted base |
| Sand | ~2,600 to 3,000 lb | Weight rises sharply when wet |
| Mulch / bark | ~400 to 800 lb | Lightest material; settles noticeably |
Key volume conversion factors
| Conversion | Factor |
|---|---|
| 1 cubic yard | 27 cubic feet |
| 1 cubic yard | 0.7646 cubic meters |
| 1 cubic foot | 0.0283 cubic meters |
| 1 cubic meter | 1.308 cubic yards |
| inches to feet | divide by 12 |
| meters to feet | multiply by 3.28084 |
Common mistakes to avoid
- Entering depth in feet when it is really inches. A 4 inch slab is 0.33 feet deep, not 4 feet. Typing 4 in a feet field overstates the volume twelvefold. Use the inches unit for slab thickness and layer depths, or divide inches by 12 first.
- Forgetting to divide by 27. Cubic feet and cubic yards are not the same. The area times depth gives cubic feet, which must be divided by 27 to reach the cubic yards that suppliers actually sell.
- Ordering exactly the calculated amount. Loose materials settle and spill, ground is rarely level, and concrete cannot easily be topped up mid-pour. Add a waste allowance of 5 to 10 percent for soil and mulch, 10 to 15 percent for gravel, and round up to a sensible order size.
- Mixing units within one calculation by hand. If you measure length in feet and depth in inches, both must be converted to the same unit before multiplying. This tool handles that per dimension, but doing it manually is a common source of error.
- Using diameter instead of radius for a round area. The circle formula uses the radius, which is half the diameter. Plugging the full diameter into pi x r squared quadruples the volume. For an 8 ft wide pad the radius is 4 ft, not 8 ft.
- Ignoring weight and delivery limits. A cubic yard of concrete weighs about 2 tons and gravel nearly 1.5 tons. Overloading a pickup or trailer is unsafe and often illegal. Check the material weight against your vehicle rating before hauling a load yourself.
Glossary
- Cubic yard
- A volume equal to a cube 1 yard (3 feet) on each side, which works out to 27 cubic feet. The standard sales unit for concrete and bulk materials in North America.
- Cubic foot
- A volume equal to a cube 1 foot on each side. There are 27 cubic feet in one cubic yard.
- Cubic meter
- The metric unit of volume, a cube 1 meter on each side. One cubic yard is about 0.765 cubic meters.
- Depth
- How thick the layer or slab is, measured downward. Often given in inches for slabs, paths and garden layers.
- Waste allowance
- Extra material, typically 5 to 15 percent depending on the material, added to cover settling, spillage and uneven ground.
- Ready-mix concrete
- Concrete batched at a plant and delivered by truck, sold by the cubic yard. Most trucks carry up to about 10 cubic yards.
- Short-load fee
- A surcharge some concrete suppliers add for deliveries below a full truckload, often around 1 to a few cubic yards.
- Compaction
- The reduction in volume when loose material like gravel or soil is pressed down. Compacted layers need more material than the loose volume suggests.
Frequently asked questions
How do I calculate cubic yards?
Measure length, width and depth in feet, multiply them together to get cubic feet, then divide by 27 to get cubic yards. If a measurement is in inches, divide it by 12 first; if it is in meters, multiply by 3.28084. This calculator does the unit conversions for you.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard, because a cubic yard is 3 feet by 3 feet by 3 feet and 3 x 3 x 3 = 27. To convert cubic feet to cubic yards, divide by 27.
How do I convert square feet to cubic yards?
Multiply the square footage by the depth in feet to get cubic feet, then divide by 27. A quick shortcut when the depth is in inches is (square feet x depth in inches) divided by 324. For example, 500 sq ft at 4 inches deep is (500 x 4) / 324 = about 6.17 cubic yards.
How many cubic yards of concrete do I need for a slab?
Take the slab length and width in feet, multiply by the thickness converted to feet (for example 4 inches is 0.333 feet), then divide the result by 27. A 10 by 10 ft slab 4 inches thick needs about 1.23 cubic yards, and most people round up to 1.25 or 1.5 yards.
How many bags of concrete are in a cubic yard?
One cubic yard of concrete takes about 45 bags of 80 lb mix, 60 bags of 60 lb mix, or 90 bags of 40 lb mix. Bagged concrete is fine for small footings and repairs, but for a full yard or more a ready-mix delivery is usually cheaper and far less work.
How much does a cubic yard of concrete weigh?
A cubic yard of poured concrete weighs about 4,000 pounds, or roughly 2 tons, depending on the mix and moisture. This matters for delivery planning and for checking whether a pickup or trailer can safely carry a load.
How do I calculate cubic yards for a round or circular area?
Use cubic yards = (3.14159 x radius x radius x depth) divided by 27, with the radius (half the diameter) and depth in feet. For an 8 ft wide pad 4 inches thick, the radius is 4 ft and depth is 0.333 ft, giving about 0.62 cubic yards.
How much is a cubic yard in cubic meters?
One cubic yard equals about 0.7646 cubic meters, and one cubic meter is about 1.308 cubic yards. This calculator shows both units side by side so you can order in whichever your supplier uses.
Should I order extra material?
Yes. Loose materials such as soil, gravel and mulch settle and spill, and ground is rarely perfectly level, so add 5 to 10 percent for soil and mulch and 10 to 15 percent for gravel. Concrete is hard to top up once a pour begins, so rounding up to the next quarter yard is wise.
Does this work for dirt, gravel and mulch as well as concrete?
Yes. The cubic yard volume is the same for any material, since it depends only on the dimensions you measure. Concrete fills the form exactly, while loose materials compact, so add a waste allowance for soil, gravel, sand and mulch, and remember they weigh very different amounts per yard.