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Concrete Calculators That Give You Yards, Bags and Cost in Seconds

Measure once and get a number you can actually order from. Use the quick estimator below, or search 500+ calculators, reference charts and plain-English guides for slabs, footings, driveways, walls and more.

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  • Updated October 2026
Muhammad Ramzan Babar, founder of ConcreteCalculate.com
Built by Muhammad Ramzan Babar PhD researcher in plasma physics (Hazara University, Quaid-e-Azam University) applying engineering math to practical construction estimates.
About the Author
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Quick Concrete Slab Estimator

Enter your slab size and get cubic yards, bags and a materials estimate as you type. Switch to metric any time.

Slab Volume and Cost Estimator

Pre-filled with a 20 ft by 10 ft slab, 4 in thick. Change any number.

Longest side of the slab
Shorter side of the slab
A typical slab is 4 inches
About 5% simple, 10% typical
Yield per bag of standard mix
Example price. Enter your supplier quote.

Your estimate

2.72
Cubic yards
123
80 lb bags
200
Square feet
$448
Materials estimate

Equivalent to 2.08 cubic meters, including waste.

Note: The cost uses the example price above and covers concrete only, not labor, forms, base or delivery fees. Ready-mix is usually ordered by rounding up to the next quarter yard. For local rates, try the Florida, Texas, California, Ohio, Georgia, or all state calculators.
Use the full calculatorAdvanced slab tool
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96 calculators

Concrete Calculators

Volume, slabs, walls, stairs, piers, columns, bag tools and ready-mix estimates.

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Rebar, gravel, sand, crushed stone, base material, blocks, pavers and drainage.

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Cost Calculators

Labor, delivery, pumping, repairs, bids, markup and state-by-state pricing.

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Engineering Calculators

Loads, PSI strength, rebar spacing, curing, shrinkage, footings and beams.

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Project Planning

Timelines, schedules, delivery planning, stairs and waste forecasting.

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Reference tables

Construction Charts

Rebar, PSI, mix ratios, spans, fasteners and pipe sizes at a glance.

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How-to articles

Guides and Tutorials

Pouring, curing, cracking, strength and cost explained in plain English.

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Concrete vs asphalt, pavers, gravel, wire mesh and bagged mixes.

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Concrete Tools

Concrete Volume and Project Calculators

Volume, cost, mix ratio, walls, columns, stairs, piers and specialty pours.

Concrete Cost Calculator

Budget a pour from size, waste and pricing assumptions.

Mix Ratio Calculator

Cement, sand and aggregate by volume for common mixes.

Pad Calculator

Equipment, HVAC and generator pads.

Volume Calculator

Cubic yards and cubic feet for standard and custom shapes.

Wall Calculator

Retaining walls, foundation walls and vertical sections.

Column Calculator

Square, rectangular and round columns.

Steps Calculator

Stairs, transitions and outdoor stoops.

Ready-Mix Truck

Truck loads, yard limits and delivery planning.

Pier Calculator

Piers, isolated footings and support posts.

Sidewalk Calculator

Sidewalks, walkways and pedestrian flatwork.

Circular Concrete

Round slabs, fire pits and ring-shaped pours.

Sonotube Calculator

Concrete for tube forms by diameter and height.

View All 96 Concrete Calculators
Materials

Material Quantity Calculators

Reinforcement, base layers, drainage and the support materials around every pour.

Rebar Calculator

Rebar quantity, spacing, length and weight.

Concrete Block (CMU)

Block counts, mortar and reinforcement for masonry walls.

Gravel Calculator

Gravel volume and tonnage for bases and driveways.

Crushed Stone

Drainage layers, base prep and hardscaping.

#57 Stone Calculator

Quantities of #57 stone for bases and drainage.

Sand Calculator

Mixing sand, paver bedding and leveling layers.

Paver Calculator

Paver count, base material and bedding sand.

Water-Cement Ratio

Workability, strength and durability planning.

Base Material

Base volume for slabs, pavers, foundations and pads.

Topsoil Calculator

Lawns, grading, gardens and final surface prep.

French Drain Gravel

Gravel for French drains and water control.

Excavation Calculator

Excavation volume, haul-off and soil movement.

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Cost and Pricing

Construction Cost and Budget Calculators

Project pricing, labor, delivery, pumping, repairs, bids and regional costs.

Cost Per Square Foot

Concrete cost from slab size and square footage.

Delivery Cost

Ready-mix delivery fees, short-load charges and dispatch.

Driveway Cost

Driveway installation with prep, labor and finishing.

Patio Cost

Patio pricing with size, finish and labor.

Foundation Cost

Excavation, formwork, rebar and pour labor.

Sidewalk Cost

Walkway and sidewalk installation cost.

Concrete Labor Cost

Placing, finishing, reinforcing and cleanup labor.

Pumping Cost

Pump truck cost by pour size, access and boom distance.

Stamped Concrete Cost

Pattern, color and sealer pricing.

Concrete Repair Cost

Cracks, spalling, patches and resurfacing.

Excavation Cost

Hauling, disposal and equipment rates.

Contractor Markup

Markup and pricing targets for profitable bids.

Cost by state:FloridaTexasCaliforniaOhioGeorgiaArizonaNew YorkPennsylvania
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Engineering

Structural and Engineering Calculators

Slab loads, PSI, rebar layout, curing, shrinkage, formwork pressure and footings.

Slab Load Calculator

Slab capacity with dead and live load assumptions.

Rebar Weight per Foot

Weight per linear foot for common bar sizes.

PSI Strength

Compressive strength targets and PSI mix requirements.

Rebar Spacing

Layouts for slabs, walls, beams and reinforced sections.

Load Bearing

Load-bearing capacity for structural elements.

Set Time

Initial set time by weather, temperature and mix.

Curing Temperature

Temperature effects on strength gain and timing.

Shrinkage

Shrinkage for crack control and joint planning.

Formwork Pressure

Lateral pressure on formwork during placement.

Rebar Cover

Cover for durability, corrosion resistance and detailing.

Footing Size

Footing width from load and soil bearing.

Beam Deflection

Deflection for beams under common loads.

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Project Planning

Schedule, Timeline and Planning Tools

Timelines, delivery logistics, waste forecasting, stairs and area math.

Project Timeline

Project duration from prep through curing milestones.

Construction Schedule

Milestones, sequencing and activity timing.

Material Delivery Planner

Delivery timing, truck counts and placement-day logistics.

Waste Estimator

Construction waste for dumpster sizing and haul-off.

Stair Calculator

Rise, run and stringer layout for stairs.

Square Footage Calculator

Area for rooms, slabs and irregular shapes.

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The Math, Explained

How a Concrete Estimate Works

Every volume calculator here follows the same three steps. Knowing them lets you sanity-check any number you get, on this site or anywhere else.

  1. Get the volume in cubic feet

    Multiply length by width by depth. Convert depth to feet first by dividing inches by 12.

  2. Convert to cubic yards

    Divide cubic feet by 27. As a shortcut, yards equal length in feet times width in feet times depth in inches, divided by 324.

  3. Add waste, then round up

    Use about 5% for simple pours and 10% for most residential jobs, more for complex shapes. Round ready-mix orders up to the next quarter yard.

Worked example: 20 ft by 10 ft slab, 4 in thick

20 × 10 × (4 ÷ 12) = 66.7 cubic feet, which is 2.47 cubic yards. With 10% waste that becomes 73.3 cubic feet, or 2.72 cubic yards. In 80 lb bags at 0.60 cubic feet each, that is 123 bags.

Area covered by one cubic yard (before waste)
Slab thicknessArea covered
3 in108 sq ft
4 in81 sq ft
5 in64.8 sq ft
6 in54 sq ft
8 in40.5 sq ft
Bags needed per cubic yard
Bag sizeYield per bagBags per yard
40 lb0.30 cu ft90
60 lb0.45 cu ft60
80 lb0.60 cu ft45

Four mistakes that cause short loads

  • Mixing units. Depth in inches against length in feet is the most common error. Convert depth to feet first.
  • Ordering the exact number. Uneven subgrade, form movement and spillage all use concrete, so always add waste.
  • Forgetting the base. Gravel and subbase are separate quantities. Use the gravel calculator and base material calculator.
  • Skipping the price check. Delivery, minimum-load and short-load fees change the total. Compare with the delivery cost calculator.
Why ConcreteCalculate

Built for Real Construction Decisions

Practical tools that show their work, not oversimplified guesses.

Transparent Math

Results are plain arithmetic on your inputs, with waste factors shown, so you can check every number yourself.

Editable Pricing

Cost tools take your own supplier price, so budgets reflect your market instead of a generic average.

Jobsite Ready

Use any calculator on a phone, tablet or desktop. No app to install.

Beyond Volume

Concrete, materials, engineering, cost, planning, charts and guides in one organized hub.

Instant Results

Answers update as you type. No sign-up walls, paid tiers or long forms.

Completely Free

Every calculator, chart and guide is free, with no registration.

Quick Reference

Construction Charts and Reference Tables

Lookup tables for curing, rebar, strength, mix ratios, spans and fasteners, with no calculation needed.

Concrete Curing Time Chart

Strength gain with walk-on and drive-on timing.

Rebar Size Chart

Bar number, diameter and weight.

Footing Size Chart

Footing width and depth reference.

Mesh Reinforcement Chart

Welded wire mesh sizes and spacing.

Concrete PSI Chart

Common strengths and where each is used.

Mix Ratio Chart

Cement, sand and aggregate ratios.

Rebar Weight Chart

Weight per foot for standard bars.

Slab Thickness Chart

Recommended thickness by application.

Water-Cement Ratio Chart

Ratios for strength, durability and workability.

Joist Span Chart

Maximum joist spans by size and spacing.

PVC Pipe Size Chart

Diameters, schedules and wall thickness.

Anchor Bolt Size Chart

Diameter, embedment depth and spacing.

Browse All Construction Charts
Knowledge Hub

Concrete Guides and How-To Articles

Straight answers on strength, timing, weather, cracking and cost.

Concrete PSI Guide

What 2500, 3000 and 4000 PSI concrete are used for.

How to Pour a Concrete Slab

Prep, forms, pour sequence, finishing and curing.

Does Concrete Need Rebar?

When reinforcement is required and when it is not.

Concrete Temperature Limits

Safe pouring temperatures in hot and cold weather.

Why Is My Concrete Cracking?

Common causes of cracking and how to prevent them.

Curing and Drying Time

When concrete sets, cures and dries.

When Can You Drive on Concrete?

Vehicle timing after a fresh pour.

How Many Yards Do I Need?

Order the right amount, not too little.

Browse All Guides
Side-by-Side

Compare Materials and Methods

Direct comparisons to help you choose between materials, methods and brands.

Concrete vs Asphalt Driveways

Durability, upkeep, cost and lifespan.

Gravel vs Concrete Driveway

Cost, maintenance and durability trade-offs.

Stamped Concrete vs Pavers

Appearance, cost and long-term maintenance.

Rebar vs Wire Mesh

Reinforcement choices for slabs and crack control.

Ready-Mix vs Bagged Concrete

Cost and convenience for small versus large pours.

Sakrete vs Quikrete

Price, consistency and availability of two bagged mixes.

View All Comparisons
Built by an Expert

The Person Behind the Calculators

Practical formulas, transparent logic and real estimating needs.

Muhammad Ramzan Babar, developer of ConcreteCalculate.com
ORCID researcher profile

Muhammad Ramzan Babar

PhD Researcher in Plasma Physics and Construction Calculator Developer
ORCID 0009-0002-4235-909X LinkedIn profile

Muhammad Ramzan Babar is a PhD researcher in plasma physics at Hazara University, Mansehra, with experimental work at Quaid-e-Azam University, Islamabad. He builds these calculators from standard estimating formulas and applied physics, and shows the inputs and waste factors behind each result so you can check the math. Spotted an error or want a tool added? Email us and we will review it.

Applied physicsEngineering mathConstruction estimatingCalculator development
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Calculator results are planning estimates. Confirm quantities, prices and local requirements with your supplier, and have a licensed professional verify structural or code-regulated work. Last updated October 16, 2026.

Common Questions

Frequently Asked Questions

Quick answers about accuracy, bags, waste and how to use the site.

Are all calculators free to use?

Yes. Every calculator, chart and guide on ConcreteCalculate.com is free, with no registration or paid tier.

How accurate are the concrete calculators?

Results are straightforward arithmetic on the numbers you enter, so they are only as good as your measurements. Add a waste allowance, round ready-mix orders up to the nearest quarter yard, and confirm quantities and pricing with your supplier. For structural or code-regulated work, have a licensed engineer confirm the design.

How much concrete does a 4-inch slab need?

A 4-inch slab takes 1 cubic yard for every 81 square feet, before waste. A 20 ft by 10 ft slab is about 2.47 cubic yards, or about 2.72 cubic yards with 10% waste.

How many bags make a cubic yard?

An 80 lb bag yields about 0.60 cubic feet, so 45 bags make a cubic yard. A 60 lb bag yields about 0.45 cubic feet (60 bags per yard) and a 40 lb bag about 0.30 cubic feet (90 bags per yard).

What waste factor should I use?

Common guidance is about 5% for simple, well-measured rectangular pours, 10% for most residential jobs, and 10 to 15% for complex shapes, hand-mixed pours or poor access.

Why does a calculator estimate differ from a contractor quote?

Calculators estimate materials and typical rates. A quote also reflects local prices, site access, ground preparation, minimum-load or short-load fees and contractor markup, so treat calculator costs as a budgeting starting point.

Which calculator should I start with?

Use the quick estimator on this page for a rectangular slab. For a specific project use the slab, driveway, patio or footing calculator, then open the cost calculators to build a budget.

Do the tools work on phones, and can I use them for work projects?

Yes to both. The tools are built for phones and desktops and are used for residential, commercial and DIY estimating. Verify final quantities and any engineering values before ordering or building.