Formula Used
Rectangular slab, footing, wall, or curb: Cubic feet = Length × Width × Depth.
Square column: Cubic feet = Side × Side × Height.
Round column: Cubic feet = π × Radius² × Height.
Tube column: Cubic feet = π × (Outer Radius² - Inner Radius²) × Height.
Cubic yards: Cubic yards = Cubic feet ÷ 27.
Waste adjusted yards: Total yards = Cubic yards × (1 + Waste percentage ÷ 100).
Bag count: Bags = Adjusted cubic feet ÷ Bag yield. The result rounds up.
How to Use This Calculator
Select the concrete shape that matches your project. Enter the required dimensions and choose the correct unit beside each field. Use length, width, and depth for slabs, footings, walls, and curbs. Use outer diameter and height for round columns. Use both diameters for tube columns.
Enter the number of matching pours in the quantity field. Add a waste percentage for spillage, uneven ground, and form variation. Enter a bag yield when planning small bagged concrete jobs. Enter a cubic yard price when estimating ready mix cost. Press the calculate button to view results above the form.
Concrete Cubic Yards Guide
Why Yardage Matters
Concrete orders are usually placed in cubic yards. A small error can waste money. A larger error can stop a pour. This calculator helps you compare slab, footing, wall, column, curb, and tube shapes. It also lets you add quantity, waste, bag yield, and price. The result gives base volume, adjusted volume, rounded order volume, bags, and estimated cost.
Measure Before You Order
Good results start with careful field measurements. Measure the real length, width, thickness, height, or diameter after forms are set. Do not rely only on plan notes. Soil, framing, and excavation can change actual dimensions. Check several points when the base is uneven. Use the largest practical thickness when the surface varies. That approach reduces shortage risk during placement.
Shape Options
Rectangular slabs, footings, walls, and curbs use length times width times depth. Round columns use the area of a circle times height. Tube shapes subtract the inner circle from the outer circle before height is applied. The calculator converts supported units to feet first. It then divides cubic feet by twenty seven to return cubic yards.
Waste And Ordering
Waste covers spillage, uneven subgrade, over excavation, form bowing, and small finishing losses. Many small jobs use five to ten percent waste. Complex pours may need more. Ready mix suppliers may also require minimum orders or charge short load fees. The rounded order field helps you order by quarter yard increments. Always confirm local supplier rules before calling.
Bag Planning
Bag yield is useful for small jobs, patch work, fence posts, and repairs. Enter the yield printed on the bag. The calculator divides adjusted cubic feet by that yield. It then rounds up because partial bags still require buying a full bag. Ready mix is usually better for large slabs because mixing many bags is slow and tiring.
Cost Review
The price field gives a planning estimate only. It multiplies adjusted cubic yards by your entered price. Delivery, pump rental, reinforcement, finishing tools, taxes, and waste disposal are separate items. Use the estimate as a budget check, not a final quote. For structural work, confirm dimensions, mix strength, reinforcement, and site conditions with a qualified professional before any major pour.
FAQs
1. What is a cubic yard of concrete?
A cubic yard is a volume measuring 3 feet long, 3 feet wide, and 3 feet high. It equals 27 cubic feet.
2. Why does the calculator divide by 27?
Concrete volume is often found in cubic feet first. One cubic yard contains 27 cubic feet, so cubic feet are divided by 27.
3. How much waste should I add?
Many simple pours use 5% to 10% waste. Irregular forms, rough subgrades, and difficult access may need more allowance.
4. Can I use inches for slab thickness?
Yes. Enter the slab thickness and choose inches as the depth unit. The calculator converts it before finding cubic yards.
5. What field is used for wall thickness?
For walls, use length for wall length, width for wall thickness, and depth for wall height. Select the matching units.
6. How are round columns calculated?
Round columns use the circle area formula. The calculator finds radius from diameter, then multiplies area by column height.
7. Why is the order rounded to quarters?
Ready mix orders are often placed in practical increments. Quarter yard rounding gives a simple planning number for supplier calls.
8. Is this enough for structural design?
No. This estimates volume and cost. Structural concrete work needs proper design, reinforcement checks, mix selection, and site review.