Home & Construction category
Material, utility, and project planning calculators for home jobs.
Concrete Calculator
Estimate how much concrete you need for slabs, footings, walls, columns, and stairs. Add multiple pours, include waste, and instantly see volume, bag counts, and estimated cost.
Concrete Sections
Mix slabs, footings, walls, and stairs in one estimate, then total everything together.
Patios, shed pads, driveways, and rectangular pours.
Cubic Yards
0
Cubic Feet
0
Cubic Meters
0
Total Concrete Needed
Includes a 10% waste factor for spillage, over-excavation, and uneven forms.
Total Cubic Yards
0
Total Cubic Feet
0
Total Cubic Meters
0
Ready-Mix Bags Needed
40 lb bags
0
60 lb bags
0
80 lb bags
0
Estimated Material Cost
$0
Based on $0 per cubic yard.
EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.
Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.
Learn more about our review process on the EveryCalc methodology page.
Calculation notes and example
Concrete volume and bag formulas
Each section is converted to cubic feet before totals are combined. Rectangular slabs, walls, and footings use length × width × depth; round columns use π × radius² × height; stair volume adds the landing or slab portion to the stepped triangular profile. The optional waste factor multiplies the base volume before conversion. Cubic yards equal cubic feet divided by 27, cubic meters use the standard volume conversion, and bag counts round up from the selected bag's nominal yield.
Slab order example
A 20-foot by 12-foot slab at 4 inches thick has a base volume of 80 cubic feet, or about 2.96 cubic yards. Turning on 10% waste raises the order estimate to about 3.26 cubic yards. If ready-mix costs $175 per cubic yard, the material estimate is roughly $570 before delivery minimums, short-load charges, reinforcement, forms, pumping, labor, or finishing.
Measurement and ordering checks
- Measure depth at several points; uneven excavation can consume more concrete than the nominal drawing depth.
- Confirm bag yield on the product label because mix and package yield can differ from the calculator's planning constants.
- Round a ready-mix order with the supplier after reviewing forms, subgrade, reinforcement, access, weather, and placement plan.
Useful companion tools: Square Footage Calculator, Unit Converter, Rehab Budget Calculator, and ADU Cost Calculator.
How to interpret the concrete result
Best use
Use the result to size a project, compare materials, estimate a reserve, or decide whether a contractor quote is in the expected range.
Cross-check
Compare the estimate with local code, site measurements, supplier pricing, utility bills, permit rules, and contractor scopes before buying materials.
Watch for
Project estimates are sensitive to waste, labor, access, climate, soil, and existing conditions. Add contingency when the job cannot be measured cleanly.
This page belongs to the Home & Construction calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.
Before relying on this concrete estimate
Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.
Measure the actual site
Square footage, slope, access, waste, existing conditions, and local material availability can change a project estimate quickly.
Add contingency
Cuts, breakage, delivery issues, weather, permits, and hidden repairs often make the real budget higher than a clean calculation.
Compare with local pricing
Supplier quotes, contractor scopes, code requirements, and permit fees should control the final budget.
Rerun this page after new measurements, contractor quotes, material price changes, permit comments, or scope changes.
Sources used for this calculator
These primary or official references help define the rules, terminology, safety checks, or source documents behind this estimate. Source links were checked in July 2026. They do not turn the calculator output into a quote, appraisal, tax determination, or professional opinion.
- Metric and U.S. customary volume conversions
National Institute of Standards and Technology
Reference for converting cubic feet, cubic yards, and cubic meters after the shape volume is calculated.
- Concrete and concrete products safety
Occupational Safety and Health Administration
Concrete volume is only a material estimate; formwork, reinforcement, placement, curing, and worker safety need project-specific review.
How to Use
- Choose whether your measurements are in feet plus inches or meters.
- Add one or more concrete sections, then pick the shape that matches each pour area.
- Enter the dimensions for every section, such as slab length and thickness or stair rise and run.
- Optional: turn on the 10% waste factor and enter your local price per cubic yard for a quick cost estimate.
- Review the combined totals in cubic yards, cubic feet, cubic meters, and ready-mix bag counts.
Frequently Asked Questions
How much concrete is in a cubic yard?
One cubic yard of concrete equals 27 cubic feet or about 0.7646 cubic meters. Ready-mix suppliers typically sell concrete by the cubic yard.
Should I add extra concrete for waste?
Usually yes. Many contractors add 5% to 10% extra to cover uneven subgrades, spillage, over-excavation, and variation in forms. This calculator includes an optional 10% waste factor.
What is the difference between concrete and cement?
Cement is one ingredient in concrete. Concrete is made from cement, sand, gravel or aggregate, and water. Most people asking for cement volume actually mean concrete volume.
How many bags of concrete do I need?
That depends on the bag size and total volume. As a rule of thumb, an 80 lb bag yields about 0.6 cubic feet, a 60 lb bag yields about 0.45 cubic feet, and a 40 lb bag yields about 0.3 cubic feet.
Is it better to buy bags or order ready-mix?
For small jobs like fence posts or a few footings, bagged concrete is often practical. For larger pours, ready-mix is usually faster, more consistent, and often more cost-effective once you need around a yard or more.
Related Calculators
More tools for this decision
More Home & Construction Calculators
Browse all home & construction →Paint Calculator
Estimate paint for walls and ceilings, subtract doors and windows, and total gallons, quarts, and project cost across multiple rooms.
Roof Replacement Budget Calculator
Estimate roof replacement cost by square footage, material (asphalt, metal, tile), and pitch complexity to size a sinking fund.
HVAC Replacement Cost Calculator
Estimate HVAC replacement cost from tonnage, SEER rating, and installation complexity for central air or heat pump systems.
ADU Cost Calculator
Accessory Dwelling Unit (ADU) construction cost — detached, attached, or garage-conversion — by sqft and scope.
Keep exploring