cubic feet to cubic yards calculator
A cubic feet to cubic yards calculator divides by 27, because a yard cube is 3 × 3 × 3 ft. 100 ft³ is 3.704 yd³, and the same volume holds 748.1 gallons.
Cubic feet to cubic yards: divide by 27
This cubic feet to cubic yards calculator divides your cubic feet by 27 to give cubic yards, shown to three decimals, and multiplies the same number by 7.48052 to give US gallons. A cubic yard is a 3 × 3 × 3 ft cube, so it holds exactly 27 cubic feet.
Enter any number of cubic feet. The default of 100 ft³ converts to 3.704 yd³ and 748.1 gallons.
Why the number is 27
Picture a cubic yard as a box you could stand in, 3 feet on every side. Fill the bottom layer with one-foot cubes: 3 rows of 3 is 9 cubes. Stack three layers and you have 27 cubes.
That is why tape-measure math lands in cubic feet first. You measure in feet, multiply length × width × depth, and get cubic feet. Bulk suppliers then want the order in yards, so you divide by 27.
Worked examples
- The default: 100 cubic feet
- Cubic yards: 100 ÷ 27 = 3.704 yd³
- Gallons: 100 × 7.48052 = 748.1 gal
- Garden bed: 20 ft × 10 ft, 4 in deep
- Depth in feet: 4 ÷ 12 = 0.333 ft
- Cubic feet: 20 × 10 × 0.333 = 66.67 ft³
- Cubic yards: 66.67 ÷ 27 = 2.469 yd³
If your supplier sells in half yards, order 2.5 yards. If you want a margin for settling, order 3.
- Bagged soil check: 50 cubic feet
- Cubic yards: 50 ÷ 27 = 1.852 yd³
- In 2 ft³ bags: 50 ÷ 2 = 25 bags
Conversion table
| Cubic feet | Cubic yards | Gallons |
|---|---|---|
| 1 | 0.037 | 7.5 |
| 10 | 0.370 | 74.8 |
| 27 | 1.000 | 202.0 |
| 50 | 1.852 | 374.0 |
| 100 | 3.704 | 748.1 |
| 200 | 7.407 | 1,496.1 |
| 350 | 12.963 | 2,618.2 |
| 1,000 | 37.037 | 7,480.5 |
Converting in your head
Dividing by 27 in your head is awkward. Two shortcuts are close enough for a phone call with a supplier.
- Divide by 30, then add 10%. 100 ÷ 30 = 3.33, plus 10% is 3.67. The exact answer is 3.704, so this lands within about 1%.
- Count in 27s. 27 is one yard, 54 is two, 81 is three, 108 is four. A 100 cubic foot job is a little under four yards.
Both tricks also work in reverse. To estimate cubic feet from yards, multiply by 27, or multiply by 30 and take away 10%. For an order that matters, run the exact figure through the calculator before you pay.
Where cubic yards are the selling unit
| Material | Sold by | Note |
|---|---|---|
| Ready-mix concrete | Cubic yard | Plants batch in yards |
| Mulch and wood chips | Cubic yard (bulk) or cubic feet (bags) | Bags are often 2 ft³ |
| Topsoil, fill dirt, compost | Cubic yard | Some yards also sell by ton |
| Gravel and stone | Ton or cubic yard | Convert with the cubic yards to tons calculator |
| Dumpsters | Cubic yard of capacity | A 10 yard bin holds 270 ft³ |
How to get cubic feet in the first place
- Rectangles: length × width × depth, all in feet. Convert inches by dividing by 12.
- Circles: 3.1416 × radius × radius × depth.
- Odd shapes: split them into rectangles and circles, add the cubic feet, then convert once.
If you would rather start from length, width, and depth, the cubic yard calculator does both steps for you.
Common mistakes
- Dividing by 9. Nine converts square feet to square yards, which is area, not volume. For volume it is always 27.
- Leaving depth in inches. 20 × 10 × 4 = 800 is not cubic feet. You must turn 4 inches into 0.333 ft first, or your yards come out 12 times too big.
- Ordering exactly the converted figure. Loose material settles and spreads thin at edges. Most people add 5–10%.
- Mixing up tons and yards. A yard of gravel weighs well over a ton. Check which unit your supplier quotes before ordering.
To go back the other way, use the cubic yards to cubic feet calculator.
Frequently asked questions
How many cubic feet are in a cubic yard?
27. A cubic yard is a cube 3 ft long, 3 ft wide, and 3 ft tall, and 3 × 3 × 3 = 27. So converting cubic feet to cubic yards always means dividing by 27, and going the other way means multiplying by 27.
Why do I divide by 27 and not by 3?
Because volume has three dimensions. One yard is 3 feet, but a cubic yard is 3 feet in each of three directions. Dividing by 3 would convert only one side. Dividing 100 cubic feet by 3 gives 33.3, which is far too high. The right answer is 100 ÷ 27 = 3.704 cubic yards.
Do suppliers round up cubic yard orders?
Many bulk yards sell in half or quarter yard steps, and ready-mix plants often sell in quarter yards with a fee on small loads. A result of 3.704 yards usually becomes a 3.75 or 4 yard order. Ask your supplier for its increments.
What is the gallon figure used for?
It shows the same space as liquid capacity: one cubic foot holds 7.48052 US gallons. That is useful for ponds, tanks, raised-bed watering, and checking bag sizes, since bagged soil and mulch are often labeled in cubic feet or quarts.
How many bags make a cubic yard?
Divide 27 by the bag size in cubic feet. It takes 13.5 bags of 2 cubic feet, 18 bags of 1.5 cubic feet, or 27 bags of 1 cubic foot to make one cubic yard. Round up when you shop.
Estimates only. Verify quantities with your supplier before purchasing.