Concrete quantities and pricing
Concrete Calculator
Calculate concrete yards, cubic feet, cubic meters and whole bags from measured flatwork. Check thickness, yield and ordering allowances.
Measure concrete volume
Editable prices are planning allowances, not quotes. Unpriced work stays unknown.
Enter your measurements to start the worksheet.
Your worksheet
Start with the dimensions and planned thickness, or enter billed yards. Your worksheet updates as you enter a complete set of measurements.
Complete the required inputs to update the worksheet.
Planning estimate, not a quote. Calculation methods and price limits.
Angi $110-$150, HomeGuide $119-$147 and Concrete Network $160-$195 have different delivery inclusions. Low/high span these published supply ranges; typical $133 is the median of their midpoints. This is a supply allowance, not an installed budget. Delivery, short loads, tax and placing remain unknown. Add a separate delivery charge only after checking what your selected per-yard price already includes.
Measurement diagram and manual formula
Convert all dimensions to one unit before multiplying. Circle area = π × (diameter ÷ 2)². Add only nonoverlapping sections. Cubic yards = cubic feet ÷ 27. Whole bags = round up adjusted cubic feet ÷ published yield. Display rounding does not set a supplier order increment.
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Sections11
- Choose geometry and units in the concrete calculator
- Measure each concrete section
- Volume, allowance and bag yield
- Worked example and rounding
- Amount versus installed cost
- Ordering checklist
- Keep measurements and yield together
- More in this topic
- National supply defaults in the concrete calculator
- FAQ: concrete amounts
- Verdict on the concrete calculator amount
Use this concrete calculator to turn measured flatwork into cubic yards, cubic feet or cubic meters. It accepts rectangles, a circular pad or a measured area. Add separate sections without overlap. Choose a verified bag yield only if you need a bag count. The tool calculates quantity and a ready-mix supply allowance. It does not choose slab design or price installed work.
Concrete volume is area multiplied by thickness, with every dimension converted to the same units first. The net result describes the space to fill. An allowance adds your own extra amount. Bag counts round up using the selected mix's published yield. Supplier billing steps remain separate, and a quantity result does not include delivery plus labor or site preparation.
Choose geometry and units in the concrete calculator
Use length and width for a rectangle, full diameter for a circle, or an area you have already measured. Do not enter the same space in both area and section modes. Imperial fields use feet for plan dimensions and inches for thickness. Metric fields use meters for plan dimensions and millimeters for thickness.
The calculator converts those inputs before doing the math. It does not infer a missing thickness. Get that figure from the written project plan. Footings, columns plus walls and load-bearing work are outside this flatwork tool.
Measure each concrete section
Split an L-shaped pad into two rectangles that meet at an edge. Label them on your sketch so you do not count the corner twice. Where thickness differs, work out separate runs and combine their volumes outside the tool. Averaging an unknown thickness can hide a shortage.
Volume, allowance and bag yield
Net cubic yards equal square feet multiplied by thickness in inches, divided by 324. The denominator combines 12 inches per foot and 27 cubic feet per yard. In metric units, square meters multiplied by thickness in meters gives cubic meters.
For bags, divide allowance-adjusted cubic feet by yield per bag and round up. The October 2022 QUIKRETE Concrete Mix 1101 sheet lists approximate yields of 0.45 cubic feet for a 60-pound bag and 0.60 for an 80-pound bag. Use those yields only for this mix, not every bagged product.
Worked example and rounding
A worked 10-foot by 12-foot rectangle at an assumed 4-inch thickness needs 40 cubic feet, or about 1.48 cubic yards. At the published 0.60-cubic-foot yield, that is 67 whole bags with no allowance. The thickness is an arithmetic assumption, not a design choice.
The displayed yardage rounds to two decimals. The bag math uses the full volume, not the rounded yard figure. An order allowance and the supplier's billing step can each affect the amount you buy. Keep both separate from display rounding.
Amount versus installed cost
A yard of concrete is a volume. A dollar price per yard usually describes a material basis; an installed square-foot rate describes another scope. Use the driveway estimator for a defined installed work budget and the cost per square foot guide to compare inclusions.
Ordering checklist
- Check the footprint and planned thickness on the plan.
- Save the mix written plan and supplier's amount unit.
- Check allowance, billing steps and minimum order terms.
- Check truck access, unloading plan and delivery fees.
- Set the curing plan before the pour.
NRMCA's CIP 8 on concrete yield explains why yield needs a proper volume basis. A slab that is thicker than the sketch needs more concrete. The worksheet does not diagnose a claimed delivery shortage.
Keep measurements and yield together
Your dimensions and chosen allowance determine the volume. Bag counts also depend on the product's approximate yield. Read the calculation methods before treating display rounding as an order quantity.
Quantity math does not select an engineering thickness. Supply pricing is a separate scope.
More in this topic
- Concrete cost per square foot: compare the same installed scope.
- Concrete removal cost: separate slab removal plus hauling and waste fees.
- Cost of concrete per yard: build a delivered material bill.
- How long concrete takes to cure: distinguish curing from drying and loading.
National supply defaults in the concrete calculator
The ready-mix supply allowance starts at $110 low, $133 typical and $195 high per cubic yard. Its range spans Angi's supply guide, September 10, 2026; HomeGuide's concrete prices, January 6, 2026; and Concrete Network's price guide, July 14, 2026. Keep their different delivery inclusions separate when pricing your order.
Their ranges are $110 to $150, $119 to $147, and $160 to $195 respectively. The typical value is the median of their range midpoints. It is calculated, not an observed national average.
Sources differ in delivery inclusions, so the result is a supply allowance with unknown fees. Do not add delivery again if your selected supply rate includes it. Installation and site preparation remain separate. Every price field can be edited.
FAQ: concrete amounts
How much concrete do I need?
Measure the area and use the stated thickness to find volume. For a rectangle, multiply length by width first. Add separate areas only when they do not overlap. The net result does not contain an order allowance. Save any extra amount as a separate assumption before asking the supplier to check the order.
How do I work out concrete yardage?
Multiply square feet by thickness in inches and divide by 324. That gives cubic yards for flatwork with a constant thickness. Convert every section to the same units. Where sections have other thicknesses, work out each volume on its own and add the resulting cubic yards.
How many bags of concrete do I need?
Divide the volume in cubic feet by the published yield of the exact mix and bag size. Round that result up to whole bags. Add your chosen allowance before dividing. A bag's weight does not by itself prove its yield, so use the current product data sheet.
Does this concrete calculator include cost?
The tool now gives quantity and an editable ready-mix supply allowance. Its dated defaults have unknown delivery and site fees unless confirmed. Installed work remains outside that supply subtotal. Check the displayed sources and replace the rates with a matching written quote when available.
Verdict on the concrete calculator amount
Use the concrete calculator to put measured dimensions into a clear quantity sheet. Check the order terms with the supplier. Keep amount plus price and design as separate decisions so an assumed thickness or blank fee cannot pass as a finished written project plan.
Plan the next part of your project
Concrete Cost per Square Foot
Compare concrete cost per square foot by installed scope, thickness and exclusions. Check national ranges and worked budget examples.
Read the guide
Concrete Removal Cost
Estimate concrete removal cost from area, thickness and demolition rates. Separate hauling, disposal, access, permits and unknown work.
Read the guide
Cost of Concrete per Yard
Calculate concrete material cost per yard using dated source ranges. Separate delivery, short loads, waiting charges, taxes and exclusions.
Read the guide
How Long Does Concrete Take to Cure
Separate concrete setting, curing, strength gain and drying. Read source-based timelines, weather limits and a curing-plan checklist.
Read the guide