Convert Cubic Feet To Cubic Yards For Concrete, Or Calculate The Volume From Length, Width And Depth Before Converting It. The Calculator Can Also Add A Waste Allowance, Estimate Concrete-Only Cost, And Show An Optional Bag Count When You Enter The Yield Printed On Your Concrete Bag. Every Numeric Entry Starts At 0 So The Result Comes Only From The Values You Enter.
Select One Of The Four Options Below. All Numeric Inputs Start At 0. Enter Your Measurements, Then Press Calculate Concrete Volume To Reveal The Result.
Your Result Will Appear Here After You Press Calculate Concrete Volume.
The PDF Includes The Calculation Mode, Base Cubic Feet, Base Cubic Yards, Waste Allowance, Rounded Planning Quantity, Optional Bag Estimate And Optional Concrete Cost.
A Cubic Yard Is Three Feet Long, Three Feet Wide And Three Feet High. Multiplying Those Three Dimensions Gives 27 Cubic Feet, Which Is The Exact Relationship Used By The Calculator.
The Tool Keeps The Exact Unit Conversion Separate From Job-Site Planning Adjustments So You Can See The Base Volume First, Then Decide Whether To Add Waste, Order Rounding, Bag Yield Or Cost.
Enter A Known Cubic-Foot Volume Or Let The Calculator Build It From Dimensions.
Convert The Base Volume To The Unit Commonly Used For Ready-Mix Concrete Orders.
One Cubic Yard Contains Exactly 27 Cubic Feet.
Add Only The Extra Percentage You Want For Real-World Variations.
Enter Your Own Price Per Cubic Yard Instead Of Using A Fixed Market Assumption.
Save The Main Conversion And Planning Numbers For Your Project Notes.
Concrete quantity is a volume problem. Square feet describe surface area, but a concrete order must also account for thickness. Once a project is expressed in cubic feet, converting that volume to cubic yards is straightforward because one cubic yard contains exactly 27 cubic feet. The basic conversion is useful for slabs, patios, sidewalks, driveways, footings, pads, steps, repair pours and many other concrete jobs where measurements may begin in feet and inches while ready-mix pricing is quoted by the cubic yard.
The Cubic Feet to Cubic Yards Concrete Calculator above separates the geometric calculation from planning choices. That distinction matters. Dividing cubic feet by 27 gives the exact mathematical conversion. Adding a waste allowance, rounding an order, or estimating bags are separate decisions that depend on the project, the accuracy of the measurements and the way the concrete will be supplied.
Cubic Yards = Cubic Feet ÷ 27For example, 54 cubic feet of concrete equals 2 cubic yards because 54 ÷ 27 = 2. A volume of 81 cubic feet equals 3 cubic yards. A volume of 13.5 cubic feet equals 0.5 cubic yard. Because the relationship is exact, you do not need an approximate conversion factor when moving directly between these two U.S. customary volume units.
Cubic Feet = Cubic Yards × 27The reverse conversion is equally simple. Multiply cubic yards by 27. This can be useful when a supplier quote is in cubic yards but a bagged product, small mixer, form, or project plan is described in cubic feet. For example, 1.5 cubic yards equals 40.5 cubic feet, while 4 cubic yards equals 108 cubic feet.
| Cubic Feet | Cubic Yards | Calculation |
|---|---|---|
| 1 ft³ | 0.0370 yd³ | 1 ÷ 27 |
| 5 ft³ | 0.1852 yd³ | 5 ÷ 27 |
| 10 ft³ | 0.3704 yd³ | 10 ÷ 27 |
| 13.5 ft³ | 0.5000 yd³ | 13.5 ÷ 27 |
| 20 ft³ | 0.7407 yd³ | 20 ÷ 27 |
| 27 ft³ | 1.0000 yd³ | 27 ÷ 27 |
| 40.5 ft³ | 1.5000 yd³ | 40.5 ÷ 27 |
| 54 ft³ | 2.0000 yd³ | 54 ÷ 27 |
| 81 ft³ | 3.0000 yd³ | 81 ÷ 27 |
| 108 ft³ | 4.0000 yd³ | 108 ÷ 27 |
A yard is three feet long. Volume is three-dimensional, so the length relationship must be applied in all three directions: length, width and height. A cube measuring 1 yard on every side therefore measures 3 feet by 3 feet by 3 feet. Multiplying 3 × 3 × 3 gives 27 cubic feet. This is why dividing by 27 converts cubic feet to cubic yards. NIST lists the international foot as exactly 0.3048 meter and the yard as exactly 0.9144 meter, supporting the exact 3-to-1 length relationship used here. You can review the official conversion-factor guidance in the NIST Guide to the SI conversion factors.
If you do not already know the cubic feet, calculate volume from the project dimensions first. For a rectangular slab or pad, multiply length in feet by width in feet by depth in feet. Because concrete thickness is commonly measured in inches, divide the depth in inches by 12 before multiplying.
Cubic Feet = Length (ft) × Width (ft) × [Depth (in) ÷ 12]Suppose a patio is 12 feet long, 10 feet wide and 4 inches thick. The 4-inch thickness equals 0.3333 foot. The volume is approximately 12 × 10 × 0.3333 = 40 cubic feet. Dividing 40 by 27 gives approximately 1.4815 cubic yards before any waste or ordering allowance is added.
If the surface area is already known, you do not need to re-enter length and width. Multiply square feet by depth in feet to get cubic feet, then divide by 27. The Area + Depth option in the calculator performs both steps. This is useful when a takeoff, floor plan, paving plan or measurement app already gives the area in square feet.
Cubic Yards = Square Feet × [Depth (in) ÷ 12] ÷ 27| Concrete Thickness | Cubic Feet Per 100 ft² | Cubic Yards Per 100 ft² |
|---|---|---|
| 2 in | 16.67 ft³ | 0.6173 yd³ |
| 3 in | 25.00 ft³ | 0.9259 yd³ |
| 4 in | 33.33 ft³ | 1.2346 yd³ |
| 5 in | 41.67 ft³ | 1.5432 yd³ |
| 6 in | 50.00 ft³ | 1.8519 yd³ |
| 8 in | 66.67 ft³ | 2.4691 yd³ |
| 10 in | 83.33 ft³ | 3.0864 yd³ |
| 12 in | 100.00 ft³ | 3.7037 yd³ |
Consider a slab 20 feet long, 12 feet wide and 4 inches thick. First convert the thickness: 4 ÷ 12 = 0.3333 foot. Next calculate cubic feet: 20 × 12 × 0.3333 ≈ 80 cubic feet. Then convert to cubic yards: 80 ÷ 27 ≈ 2.963 cubic yards. If you decide to add a 5% planning allowance, the adjusted volume is approximately 3.111 cubic yards before any supplier-specific order rounding.
There is no universal waste percentage that is correct for every job. A precisely formed slab on a stable prepared base may need less contingency than an irregular excavation, a footing trench with rough sides, or a project with multiple transitions and thickened areas. The calculator therefore starts the waste field at 0 rather than assuming a percentage for you.
Before adding extra concrete, consider measurement accuracy, subgrade variation, form movement, trench over-excavation, thickened edges, beams, steps, slopes, pump or chute handling and supplier minimum-order rules. For structural or engineered work, use the project drawings and supplier guidance rather than treating a generic percentage as a design rule.
The exact conversion can produce a number such as 2.963 cubic yards, but a supplier may sell or schedule concrete in specific increments and may also have minimum load or short-load policies. The calculator includes optional order rounding so you can explore a planning quantity, but it does not assume a supplier's rule. Enter the supplier's real ordering increment if you want the estimate to reflect a quote more closely.
Ready-mix concrete is commonly discussed by volume, and cubic yards are widely used in the United States. This makes ft³-to-yd³ conversion especially useful when project dimensions are measured in feet and inches. Once you know the cubic yards, you can compare the quantity with local quotes, delivery requirements and truck scheduling. For a driveway-specific workflow, use the Concrete Driveway Calculator, which is better suited to long rectangular pours and driveway sections.
For small repairs or isolated pours, bagged concrete may be more practical than a ready-mix delivery. Bag coverage is usually stated as an approximate yield, often in cubic feet. Because products and bag sizes differ, the calculator does not guess a yield. Enter the yield from the exact product packaging or technical data sheet. The tool then divides the adjusted cubic-foot requirement by your entered bag yield and rounds up to whole bags.
If bag yield is the main question, the Concrete Bag Yield Calculator provides a more detailed bag-focused workflow. If you are proportioning cement, sand and aggregate rather than using premixed bags, use the Concrete Mix Calculator.
Assume a small pad needs 9 cubic feet after the planning allowance. If the exact bag you are using states a yield of 0.60 cubic foot per bag, the planning estimate is 9 ÷ 0.60 = 15 bags. If another product yields 0.45 cubic foot per bag, the same 9 cubic feet would require 20 bags. This is why the yield field should come from the actual product rather than a generic bag weight assumption.
The optional cost field multiplies the final planning quantity in cubic yards by the price per cubic yard you enter. It is intentionally editable because concrete prices vary by supplier, region, mix specification, delivery distance, fuel charges, short-load fees, pumping requirements and other project conditions. The result should therefore be treated as a concrete-only planning number, not a complete installed-project price.
Estimated Cost = Final Planning Cubic Yards × Your Entered $/yd³ RateIf a project contains several sections with different dimensions, calculate each section separately in cubic feet and add the results before converting the total to cubic yards. This is usually more accurate than forcing an irregular shape into one large rectangle. For identical sections, the calculator's quantity field can multiply the volume automatically.
For example, if Section A is 30 ft³, Section B is 18 ft³ and Section C is 6 ft³, the combined base volume is 54 ft³. Divide 54 by 27 to get 2 yd³. Any waste allowance should then be applied according to the way you plan to order and place the concrete.
The unit conversion itself is exact. The uncertainty comes from the measurements and project assumptions. If the length, width or depth is wrong, the converted result will also be wrong. Depth deserves particular attention because small changes over a large area can materially change the volume. Measure the actual form dimensions and prepared base where appropriate, and account separately for beams, haunches, curbs, steps, piers or other shapes that add concrete.
Some specifications, product literature or international references use cubic meters instead of cubic yards. NIST's conversion tables list one cubic foot as approximately 0.02831685 cubic meter and one cubic yard as approximately 0.7645549 cubic meter. Those metric conversions are useful when comparing documentation across unit systems, but the direct ft³-to-yd³ relationship remains exactly 27 to 1. See the NIST volume conversion table for authoritative unit factors.
These Relationships Make It Easier To Check A Calculation Before You Order.
One Cubic Yard Contains Exactly 27 Cubic Feet.
One Cubic Foot Is 1/27 Of A Cubic Yard.
Divide Concrete Depth In Inches By 12 Before Multiplying Feet.
The Three-Foot Length Relationship Becomes 27 When Cubed.
The examples below show base geometric volume only unless otherwise noted. Real projects may include separate features or planning allowances.
| Example Project | Dimensions | Base Cubic Feet | Base Cubic Yards |
|---|---|---|---|
| Small Pad | 6 ft × 6 ft × 4 in | 12.00 ft³ | 0.4444 yd³ |
| Patio | 12 ft × 10 ft × 4 in | 40.00 ft³ | 1.4815 yd³ |
| Walkway Section | 30 ft × 4 ft × 4 in | 40.00 ft³ | 1.4815 yd³ |
| Driveway Section | 20 ft × 10 ft × 5 in | 83.33 ft³ | 3.0864 yd³ |
| Garage Slab Example | 20 ft × 20 ft × 4 in | 133.33 ft³ | 4.9383 yd³ |
| Thicker Equipment Pad | 10 ft × 8 ft × 8 in | 53.33 ft³ | 1.9753 yd³ |
Common Questions About Concrete Volume, ft³, yd³, Thickness, Waste And Bag Yield.
There are exactly 27 cubic feet in one cubic yard. A cubic yard is 3 feet × 3 feet × 3 feet, and 3 × 3 × 3 = 27.
Divide cubic feet by 27. For example, 54 cubic feet ÷ 27 = 2 cubic yards.
Multiply cubic yards by 27. For example, 2.5 cubic yards × 27 = 67.5 cubic feet.
100 ÷ 27 is approximately 3.7037 cubic yards before any waste or order rounding is added.
5 × 27 = 135 cubic feet.
Multiply square feet by depth in feet to get cubic feet, then divide by 27. If depth is in inches, divide the inches by 12 first.
100 square feet × 4/12 foot = about 33.33 cubic feet. Divide by 27 to get about 1.2346 cubic yards before any extra allowance.
No. The waste field starts at 0 so you decide what, if any, contingency is appropriate for your project.
Yes. Enter the bag yield in cubic feet from the exact product information. If the yield field remains 0, the calculator leaves the bag estimate blank rather than guessing.
Yes. Enter your quoted price per cubic yard. The calculator multiplies that price by the final planning quantity. The result is a concrete-only estimate and may not include delivery or other charges.
Use the supplier's actual ordering rules. The calculator offers optional rounding increments for planning, but it does not assume that every supplier uses the same increment or minimum order.
Yes. The direct relationship is exact: 27 cubic feet equals 1 cubic yard.
Official U.S. conversion-factor reference for customary and SI units, including cubic foot and cubic yard relationships to cubic meters.
View NIST Volume Conversion FactorsEstimate driveway concrete from length, width, thickness, sections, waste and cost.
Open Driveway CalculatorEstimate bags from total concrete volume and the specific yield printed on the product.
Open Bag Yield CalculatorEstimate cement, sand and aggregate quantities from a custom concrete mix ratio.
Open Mix Calculator