Concrete Calculator Hub

Concrete Volume Calculator for Yards, Bags, and Cost

Estimate concrete for slabs, pads, footings, round holes, and columns. Get cubic yards, cubic feet, cubic meters, 40/60/80 lb bags, waste, cost, and the next buying check in one place.

Enter Measurements

Raw volume before waste

33.33 ft3 / 1.23 yd3

Save this estimate or download a PDF report

The PDF report uses the current calculated result. Save the estimate first when you want to reuse the inputs later.

Results

Live estimate
Concrete Volume

1.358 yd³

36.6667 ft³ / 1.0383

Bags Needed

62 bags

Rounded up to whole bags

Estimated Cost

$310.00

Based on bag price

Waste Factor

10%

Included in total volume

Concrete estimate in yards

Your 1.358 yd3 estimate is about 62 bags after waste. Use the yard number to choose the buying path before you order.

Bags vs ready-mix comparison zone

This is the range where bagged concrete can look cheaper but delivery, short-load fees, helper availability, and placement speed can change the better option.

Next quote checks

Use this volume to compare ready-mix delivery, bagged concrete, delivery fees, short-load charges, and quote gaps before ordering.

Volume buying decision in one screen

1.36 yd3 / 36.67 ft3 / 62 bags. Decision zone. Compare bagged material, store delivery, ready-mix minimums, and short-load fees.

Metric concrete volume quick answer

For metric projects, use meters for length and width, convert thickness from centimeters to meters, then multiply. For a slab, use length m x width m x thickness cm / 100. A 10 m2 area at 10 cm thick is 1.0 m3 before waste.

Use cubic meters when talking to suppliers, then convert to bags only after checking the yield printed on the product. concrete bag calculator can help once you know whether the job is better handled with bags or delivered concrete.

Metric volume shortcuts
ShortcutUseExample
Area x thicknessFast slab or pad estimate10 m2 x 10 cm = 1.0 m3
Centimeters to metersDivide thickness by 100 before multiplying8 cm = 0.08 m
Waste allowanceAdd waste before converting to bags or ordering ready-mix1.0 m3 + 10% = 1.10 m3

Quick concrete answer

How much concrete do I need?

For the current measurements, plan on about 1.36 yd3 of concrete after waste. That is roughly 1.04 m3 and 62 bags before you choose a buying path.

Formula used

length x width x thickness, then add waste

Ordering buffer

Waste is already included. Confirm depth, subgrade, form leaks, spills, and supplier rounding before ordering.

Buying trigger

Comparison zone. Price bags, ready-mix minimums, delivery, and short-load fees side by side.

Do not stop at the volume number

The useful next step is to turn the quantity into a buying check: bags, local delivery, minimum loads, access fees, and quote scope.

Concrete calculator square feet

Square feet to concrete yards

When you know the slab area but not the yardage, use square feet and thickness first. The shortcut is square feet x thickness in / 12 / 27, while one cubic yard covers about 324 / thickness inches square feet before waste.

Current area

100 sq ft

9.29 m2

Coverage per yd3

81 sq ft

before waste

This estimate

1.358 yd3

62 bags

100 sq ft coverage by thickness
Thickness1 yd3 coversYards with waste80 lb bags
2 in162 sq ft0.679 yd331
3 in108 sq ft1.0185 yd346
3.5 in92.57 sq ft1.1883 yd354
4 in81 sq ft1.358 yd362
5 in64.8 sq ft1.6975 yd377
6 in54 sq ft2.037 yd392

Table uses the current waste factor and 80 lb bag yield of 0.6 ft3 unless your calculator result uses a different bag yield.

Measuring concrete in cubic meters for the Philippines?

Use the m3 result as the first number, then compare site-mixed bags, ready-mix delivery, pump access, VAT, rain timing, and supplier quote scope before ordering a Philippine carport, walkway, gate apron, or small slab.

Open the Philippines concrete planning page

What to do with the volume result

The cubic yard number is only the first decision. Use the result to choose a buying path, then check fees and access before you approve a supplier or contractor quote.

Volume result decision guide
Result rangeLikely next stepCheck before buying
Under 0.5 yd3Bagged concrete is usually practicalConfirm bag yield, mixing time, waste, and how many batches you can place before set time.
0.5 to 2 yd3Compare bags with ready-mix deliveryCheck minimum load, short-load fee, delivery charge, truck access, and helper availability.
Over 2 yd3Price ready-mix or review a contractor quoteConfirm PSI, slump, delivery window, chute reach, pump or buggy needs, and waiting-time rules.

Formula

Rectangular slab or pad

Volume = length x width x thicknessYards from square feet = square feet x thickness in / 12 / 271 yd3 coverage = 324 / thickness in sq ftVolume = 10 x 10 x 0.333

Waste and bags

Final volume = 33.3333 x (1 + 10%/100)Bags = ceil(final volume / 0.6)

Example Estimates

10 ft x 10 ft slab

Small patio, shed base, or pad at 4 inches thick.

Result: 1.358 yd3 / 36.6667 ft3 / 62 bags

20 ft x 12 ft driveway pad

Rectangular flatwork at 5 inches thick.

Result: 4.0741 yd3 / 110 ft3 / 184 bags

12 in round post hole

Round hole, 3 feet deep, with 10% waste.

Result: 0.096 yd3 / 2.5918 ft3 / 5 bags

When To Use This Page

  • Start here when you only know the shape and dimensions.
  • Use it for broad cubic yard estimates before choosing bags or ready-mix.
  • Move to a project-specific calculator when you need extra assumptions, such as stair landing volume or driveway waste.

Assumptions

  • Rectangular mode assumes a flat, uniform-thickness pour.
  • Round mode assumes a solid cylinder with no voids.
  • Bag yield and ready-mix ordering rules vary by product.
  • This is a material estimator, not structural advice.

Frequently Asked Questions

How much concrete do I need?
Measure the shape first, convert thickness to feet or meters, multiply to get volume, then add waste before ordering. Use the result as a buying decision: small jobs may fit bags, while larger jobs should be checked against ready-mix delivery and quote fees.
How do I calculate concrete volume?
For a rectangular pour, multiply length by width by thickness after converting all measurements to the same unit. For a round column or post hole, use pi times radius squared times height. Then add a waste factor before ordering material.
Should I use cubic yards or cubic feet?
In the United States, ready-mix concrete is usually ordered by cubic yard, while bagged concrete yield is usually printed in cubic feet. This calculator shows both so you can compare bagged concrete with delivery options.
How much waste should I add?
A 10% waste factor is a practical default for many small concrete projects. Use a higher percentage for uneven excavation, irregular forms, first-time DIY work, or pours where running short would be expensive.
Can this calculator estimate bags of concrete?
Yes. Choose the bag size and enter a bag price to estimate whole bags and material cost. Bag yield is approximate, so always check the yield printed on the product you plan to buy.
Can I calculate concrete from square feet?
Yes for rectangular slabs and pads. Multiply square feet by thickness in inches, divide by 12 to get cubic feet, then divide by 27 to get cubic yards before adding waste.
Is this calculator enough for structural work?
No. This page estimates material volume only. Structural slabs, footings, stairs, retaining walls, and code-regulated work may require a contractor, engineer, permit, or local building-code review.

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