Convert ft³ to yd³ cubic feet ↔ cubic yards Free Online Secure
Type a value in cubic feet and read it in cubic yards at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert ft³ to yd³ (cubic feet ↔ cubic yards)
| ft³ | yd³ |
|---|---|
| 1 | 0.037037037037 |
| 2 | 0.0740740740741 |
| 3 | 0.111111111111 |
| 5 | 0.185185185185 |
| 10 | 0.37037037037 |
| 20 | 0.740740740741 |
| 50 | 1.85185185185 |
| 100 | 3.7037037037 |
Where these units come from
The litre has an awkward history. From 1901 it was defined as the volume of one kilogram of pure water at its densest, which sounds elegant but came out at 1.000028 cubic decimetres — close enough to be confusing and far enough to spoil careful work. In 1964 the definition was abandoned and the litre became exactly one cubic decimetre, which it has been ever since. The gallon has a messier story still: the US gallon descends from the English wine gallon of 231 cubic inches, while Britain redefined its own in 1824 as the volume of ten pounds of water. Nobody reconciled the two, so a US gallon is 3.785411784 litres and an imperial gallon 4.54609 — about a fifth larger. The gallon, pint, cup, fluid ounce and spoons on this page are the US ones.
Where you meet them
Millilitres and litres run through daily life almost invisibly: bottles, fuel, paint, dosage, the capacity of a kettle. Cubic metres belong to water bills, concrete, shipping and the air a ventilation system has to move. Cubic centimetres name engine displacement, cubic feet appear in freight and in appliance capacities, and cups and spoons live almost entirely in recipes — which is exactly where the difference between a US cup and a metric one quietly ruins a cake.
Questions people ask
Where are cubic feet used?
In the United States for natural gas billing, refrigerator and freezer capacity, and the interior volume of shipping containers, and worldwide for airflow, where fans are rated in cubic feet per minute. A cubic foot is exactly 28.316846592 litres, so a small fridge of 4 cubic feet holds about 113 litres.
Where is the cubic yard used?
For bulk materials in the United States and Britain: concrete, soil, sand and gravel are sold by the cubic yard. It is 27 cubic feet, or exactly 764.554857984 litres, so a cubic yard is about three quarters of a cubic metre. A common mistake is to treat it as three cubic feet, when it is three feet in each direction.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Slabs, footings and fence posts: ordering concrete in cubic yards
A builder works out how much concrete a job needs in cubic feet, because the forms are measured in feet and inches, but the ready-mix plant sells it by the cubic yard. To convert ft³ to yd³ you divide by 27, since a cubic yard is three feet by three feet by three feet. A slab of 10 by 10 feet, four inches thick, holds 33.3 ft³, which is 1.23 yd³. This page divides as you type, and the text below shows how the figure turns into an order, a number of bags and a number of wheelbarrow loads.
Ahead you will find the rule with examples, a note on each unit, a comparison, a tour of concrete jobs and the slips to avoid. All arithmetic happens in your browser; nothing you enter is sent anywhere.
How to convert ft³ to yd³: divide by 27
The rule
A yard is three feet, so a cubic yard is 3 times 3 times 3, which is 27 cubic feet. To convert ft³ to yd³, divide the cubic feet by 27. So 27 ft³ is 1 yd³, 81 ft³ is 3 yd³ and 160 ft³ is 5.93 yd³. In the other direction, multiply cubic yards by 27.
Worked examples
A driveway of 12 by 40 feet, four inches thick, is 160 ft³, 5.93 yd³. A footing 12 inches wide and 8 inches deep over 100 feet is 66.7 ft³, 2.47 yd³. A wall 8 inches thick, 4 feet high and 20 feet long is 53.3 ft³, 1.98 yd³.
Why 27 and not 3
The number 3 turns feet into yards. A volume multiplies three lengths, so the factor is three cubed. Dividing by 3 leaves the answer nine times too big, which means paying for nine times as much concrete as you need.
A quick sanity test
The cubic yard is the larger unit, so the figure shrinks by a factor of 27. If your “convert ft³ to yd³” calculation result shrank by only 3 or 9 times, you used the length or area factor.
The cubic foot
A foot in each direction
The cubic foot is 28.3 litres. In construction it is the volume of a small bag of concrete mix: an 80 lb bag yields 0.6 ft³ and a 60 lb bag about 0.45 ft³.
Where it appears
Bag labels, formwork calculations, small repairs and material take-offs.
The cubic yard
Three feet in each direction
The cubic yard is 27 cubic feet, 0.7646 cubic metres. Ready-mix concrete, gravel, sand and soil are sold by it in the United States, and a truck typically carries up to 10 yards of concrete.
Where it appears
Ready-mix orders, bulk deliveries, excavation and landscaping.
Cubic foot and cubic yard compared
A cubic yard holds 27 cubic feet. Small jobs are counted in feet and bags, large ones in yards and truckloads. A homeowner who knows that 45 bags of 80 lb mix make a yard can decide whether it is cheaper to mix by hand or to order a truck.
The factor 27 is exact, but the quotient rarely is, so round to two decimals. Round up when ordering, because a shortfall during a pour is far more costly than a small surplus.
Where the conversion appears
Slabs and patios
A slab 10 by 10 feet and 4 inches thick has 100 ft² times one third of a foot, which is 33.3 ft³, 1.23 yd³. A shortcut is length in feet times width in feet times thickness in inches, divided by 324. Check: 10 times 10 times 4 divided by 324 gives 1.23. When you convert ft³ to yd³ for a slab, add 5 to 10 percent for waste and uneven ground.
Footings, walls and posts
A footing of 12 by 8 inches over 100 feet takes 2.47 yd³. A fence post hole 10 inches across and 3 feet deep holds 1.64 ft³, so twenty posts take 32.7 ft³, 1.21 yd³. A column formed with a 12 inch tube, 4 feet tall, is 3.14 ft³, 0.12 yd³. When you convert ft³ to yd³ for each element, you can add the yards for one order.
Bags and trucks
A yard of concrete needs 45 bags of 80 lb, 60 bags of 60 lb or 90 bags of 40 lb mix. A wheelbarrow of 6 ft³ takes 4.5 loads per yard. Ready-mix plants set a minimum, often 3 or 4 yards, and charge a short-load fee for less. A truck holds up to about 10 yards.
Weight of concrete
Normal concrete weighs about 150 lb per cubic foot, so a cubic yard weighs roughly 4,050 lb, over two tons. A slab of 1.23 yd³ weighs 5,000 lb. Ground, forms and the truck's access all have to handle such weights. A driveway of 5.93 yd³ is 24,000 lb, almost 11 tonnes, which explains why a heavy truck can crack a slab that is too thin.
Curbs, gutters and sidewalks
A sidewalk 4 feet wide, 4 inches thick and 100 feet long has 133 ft³, 4.94 yd³. A curb and gutter section of 2 ft³ per linear foot over 100 feet takes 200 ft³, 7.4 yd³. Highway crews think in yards per mile or per 100 feet, so a conversion from the cubic feet worked out on the plan is the first line of each estimate.
Mortar, grout and plaster
Mortar for a block wall is a small share of the whole. A wall of 100 ft² built with concrete blocks needs roughly 4 to 6 ft³ of mortar, 0.15 to 0.22 yd³, depending on joint thickness. In practice, masons buy sand by the ton and cement by the bag, but the cubic-foot estimate lets you compare quotes and avoid ordering a full yard when a quarter yard will do.
In a spreadsheet
Put the cubic feet in column A and use =A2/27 in column B. For the reverse, =B2*27. For a slab, =C2*D2*E2/324 gives yards from length and width in feet and thickness in inches. Add a column with =B2*1.1 to include a 10 percent waste factor, and round up to the next half yard for the order.
Rounding
The factor 27 is exact, but most answers are not round. Keep two decimals while you work, and round up to the next half yard when you order. Do not round down: a truck that arrives short means another delivery. Quote the calculated and the ordered figures in your notes so you can learn how close your estimates are.
A mental shortcut
Divide by 27 by dividing by 30 and adding 10 percent. For 90 ft³, 3 plus 0.3 gives 3.3 yd³, against 3.33 exactly. For 135, 4.5 plus 0.45 gives 4.95, against 5. The result is within 1 percent, fine for a first look at a job on site.
Reference values
13.5 ft³ is 0.5 yd³, 27 ft³ is 1 yd³, 54 ft³ is 2 yd³, 81 ft³ is 3 yd³, 135 ft³ is 5 yd³, 270 ft³ is 10 yd³ and 540 ft³ is 20 yd³. If you convert ft³ to yd³ and land far from this ladder, repeat the division.
Checking by reversing
To make sure your “convert ft³ to yd³” calculation result is right, multiply it by 27. If 160 ft³ gave 5.93 yd³, then 5.93 times 27 returns 160. A second check is the size of the answer: it should be 27 times smaller. If it is only 3 or 9 times smaller, you used the wrong factor.
Concrete blocks and bricks
A concrete block of 16 by 8 by 8 inches has a gross volume of 0.59 ft³, but with hollow cores the solid volume is about 0.35. A pallet of 90 blocks has a gross volume of 53 ft³, about 2 yd³, and weighs more than a ton and a half. Delivery trucks and forklifts have load limits, so check the pallet figures in cubic feet and yards before planning access to the site.
Pit and trench volumes
A pit 8 by 10 feet and 4 feet deep contains 320 ft³, 11.9 yd³, of earth in place. Once dug, the soil expands by about 25 percent, so you must haul away close to 15 yd³, one and a half truckloads. Excavators and trucks are rated in yards, and plans are drawn in feet, so a “convert ft³ to yd³” calculation step is the bridge between the drawing and the haulage.
Pour rate and time
A ready-mix truck can discharge about 1 cubic yard per minute from its chute, and a crew can place and finish roughly 1 yard in 10 to 15 minutes. A 6 yard driveway takes about an hour and a half, if the finishers keep up. Knowing the volume in yards allows the contractor to book the truck and the crew, and to decide when the concrete will start to set.
Waste and over-ordering
Forms bulge, subgrades are uneven and some mix is spilled, so a typical allowance is 5 to 10 percent. For a calculated 5.93 yd³, ordering 6.5 is prudent. A shortage means a second delivery with a short-load fee, and a cold joint where the two pours meet. A small surplus can be used for stepping stones or a base for a shed, so most builders prefer too much.
Cold weather and curing
In cold weather, concrete needs insulating blankets. A slab of 33 ft³ holds a lot of heat in its mass, but the surface can freeze if left bare. Estimating blankets starts with the surface area, but the volume tells you how much heat is generated during curing. Specifications for large pours may refer to cubic yards and temperature limits, so crews convert volumes and keep track of both units.
Decorative concrete and countertops
A kitchen countertop of 8 by 2 feet and 1.5 inches thick takes 2 ft³ of concrete, 0.074 yd³, around 300 lb. Such small volumes are mixed from bags, not trucks, and the mixes are specialised. Craftspeople quote the volume in cubic feet to match the bag labels, while architects who specify a large feature wall may give the total in cubic yards.
Bridge decks and large pours
A bridge deck of 100 by 40 feet and 8 inches thick requires 2,667 ft³, 98.8 yd³. At 10 yards a truck, that is ten trucks arriving one after another, so the pour is planned minute by minute. Contractors converting the volume from cubic feet in the design to yards on the order form keep a copy of the calculation on file, in case a delivery ticket is questioned.
Thickness in inches
Concrete thickness is given in inches, and the calculation needs feet. Four inches is one third of a foot, six inches half a foot, eight inches two thirds. For an area of 400 ft² at 6 inches, the volume is 200 ft³, 7.4 yd³. The shortcut of area times thickness in inches divided by 324 combines both steps in one, and it is easy to remember on site.
Mixing by hand
A bag of 80 lb mix needs about 1.6 gallons of water and gives 0.6 ft³. To fill a form of 10 ft³ you need 17 bags. At 25 minutes a barrow of mixing and placing, the job is a long day. A mixer drum of 9 ft³ can make about 14 bags worth at a time. When the volume passes a yard, 27 ft³, a truck becomes more attractive, and the conversion tells you where that point is.
Price per cubic yard and per cubic foot
If ready-mix costs 150 dollars per yard, the price per cubic foot is 5.56. A bag of 80 lb at 6 dollars gives 10 dollars per cubic foot, so 270 dollars per yard. A truck is cheaper for large volumes, but the delivery fee and minimum make bags competitive below about a yard. The prices on each side of the comparison must refer to the same volume unit.
Gravel base and compaction
Under a slab of 200 ft², a gravel base of 4 inches takes 66.7 ft³, 2.47 yd³, but compaction reduces the volume by 10 to 20 percent, so you order about 2.9 yd³. Gravel weighs around 1.4 tons per yard, so the base is about 4 tons. The conversion to yards allows you to use the supplier's price, and the bag arithmetic does not apply to such volumes.
Stairs, steps and landings
Take three solid concrete steps, each 6 inches high and 12 inches deep, 4 feet wide. The lowest has 2 ft³, the middle one 4 ft³ and the top one 6 ft³, giving 12 ft³, 0.44 yd³. Add a landing of 4 by 4 feet and 6 inches thick, 8 ft³, and the total is 20 ft³, 0.74 yd³. Stairs take more than a quick look suggests, so add them up step by step and convert ft³ to yd³ once at the end.
Retaining walls and footings
A retaining wall 3 feet high, 8 inches thick and 30 feet long holds 60 ft³ of concrete, 2.22 yd³, and its footing 24 inches wide and 12 inches deep takes another 60 ft³. The total of 120 ft³ is 4.44 yd³. Engineers check the design, but the order quantity comes from a simple conversion, performed once the dimensions in feet and inches are fixed.
Pool shells and tanks
A swimming pool shell of 16 by 32 feet, with an average depth of 5.5 feet and walls and floor 8 inches thick, has a surface of about 1,040 ft² and so about 700 ft³ of shotcrete, roughly 26 yd³. A septic tank of 1,000 gallons, 134 ft³ inside, with walls 4 inches thick, takes about 3 yd³. In either case, the volumes are worked out in cubic feet and then divided by 27 for the order.
More values for convert ft³ to yd³
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 ft³ = 0.0037037 yd³
- 0.5 ft³ = 0.0185185 yd³
- 3 ft³ = 0.111111 yd³
- 4 ft³ = 0.148148 yd³
- 7 ft³ = 0.259259 yd³
- 15 ft³ = 0.555556 yd³
- 20 ft³ = 0.740741 yd³
- 75 ft³ = 2.77778 yd³
- 200 ft³ = 7.40741 yd³
- 500 ft³ = 18.5185 yd³
- 2,000 ft³ = 74.0741 yd³
- 10,000 ft³ = 370.37 yd³
Mistakes when you convert ft³ to yd³
Dividing by 3 or 9
Those factors are for lengths and areas. For volumes, divide by 27.
Mixing inches and feet
Thickness is quoted in inches, length in feet. Convert the thickness to feet, or use the divide-by-324 shortcut.
Ordering the exact amount
Always add a margin. A pour that runs short is far costlier than a pour with a small surplus.
Quick answers
How many cubic feet are in a cubic yard?
27.
How do I convert ft³ to yd³?
Divide by 27.
How many cubic yards are in a cubic foot?
0.037.
What is 160 ft³ in cubic yards?
5.93 yd³.
Is the number I type stored anywhere?
No, it stays in your browser.
More pages and a closing note
For other volume conversions, see Convert ft³ to m³, Convert ft³ to in³, Convert m³ to yd³, Convert yd³ to m³, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C, Convert m to ft. The opposite direction is Convert yd³ to ft³.
In short, you convert ft³ to yd³ by dividing by 27, three cubed, and writing the unit beside the answer. Your figure is calculated on your own device, with no account and no upload.