🏗️ Concrete Calculator 2026
Calculate exactly how much concrete you need for slabs, footings, and driveways. Get cubic yards, cubic meters, bag count, weight and ready-mix cost — instantly. Free, no sign-up. 2026 US pricing.
A concrete calculator tells you exactly how much concrete you need to pour a slab, footing, driveway, or any rectangular form. It converts your dimensions into cubic yards (US ordering unit), cubic meters (metric), bag count, weight, and estimated ready-mix delivery cost. The standard volume formula for a rectangular slab is:
How to calculate concrete in 3 steps:
- Measure length, width, and thickness of the pour area. Slabs are typically 4 inches thick; driveways 4–6; structural pads 6–8.
- Pick a bag size, waste factor, and concrete grade (PSI) that match the job — 60 lb bags and 10% waste are the standard defaults.
- Click Calculate Concrete to see total cubic yards, cubic meters, bag count, total weight, and estimated ready-mix cost instantly.
For example, a 20 ft × 10 ft × 4-inch slab needs (20 × 10 × 4) ÷ 12 ÷ 27 = 2.47 cubic yards of concrete (about 2.72 yd³ with 10% waste, which you'd round up to a 2.75 yd³ order). That's roughly 149 60-lb bags, 5 tons of material, and around $421 in ready-mix delivery at typical 2026 US prices.
Concrete Calculator
Pick a shape, enter dimensions, see volume, bag count and 2026 cost instantly.
Know Exactly How Much Concrete to Order –
and What It Will Cost to Pour
Running out of concrete mid-pour creates a cold joint that weakens the slab forever. Over-ordering wastes hundreds of dollars per yard. This free calculator gives you the exact volume, bag count, weight and ready-mix cost in seconds — with 2026 US pricing.
⚡ Try the Calculator NowHow Much Concrete Do You Actually Need? Let's Find Out.
Concrete is one of the most expensive single-line items on most construction and renovation projects, and the math behind ordering it is unforgiving in both directions. Order too little and you create a cold joint that weakens the entire slab. Order too much and you've literally paid for material that gets dumped in your driveway.
The formula itself is simple — length × width × thickness — but the real cost-control work is in the surrounding decisions: how much waste to add, what bag size to buy, whether to call a ready-mix truck or rent a mixer, and which PSI grade actually fits the job. Get those right and a small DIY pour can come in under $250. Get them wrong and the same pour balloons toward $500.
This free Concrete Calculator uses 2026 NRMCA and HomeAdvisor pricing data to convert your dimensions into cubic yards, cubic meters, bag count, total weight, and delivered cost — and shows you the round-up number a ready-mix supplier will actually quote you.
How the Concrete Calculator Works
Four dimensions. Three bag/waste/grade choices. One click. Instant volume, weight, bag count, and delivered cost. Here's what each field does behind the scenes.
Enter the Length (in Feet)
Measure the long side of your slab, footing, or pad in feet. Half-foot precision is enough for almost every residential pour — concrete tolerances are forgiving by an inch or two but unforgiving by a foot. Use a long tape or wheel measure rather than a folding ruler for anything over 10 ft.
Enter the Width (in Feet)
The short dimension of the rectangle. For square slabs (garage floors, equipment pads), length and width are the same number. For complex shapes, break the area into rectangles and run the calculator once per rectangle, then sum the results.
📐 An L-shape or T-shape adds without overlap — just split it into two rectangles at the inside corner.Enter the Thickness (in Inches)
Standard thickness depends on the load. Patios and walkways = 4 inches. Residential driveways = 4–6. Garage floors = 4–6 with rebar. Heavy-vehicle pads = 6–8. Footings vary by frost depth and structural load. The slider runs from 2 to 36 inches to cover everything from veneer toppings to deep footings.
📊 Going thicker than the spec wastes money. Going thinner risks cracking and failure.Enter the Quantity
If you're pouring multiple identical slabs (4 deck-pier pads, 3 equipment bases, a set of stair landings), enter the count here. The calculator multiplies a single-unit volume by quantity for the totals. For one-of-one pours, leave this at 1.
Pick Bag Size, Waste Factor & Mix Grade
Bag size determines how many bags equal one cubic foot (60 lb yields 0.45 ft³). Waste factor adds margin for spillage, form expansion, and uneven subgrade — 10% is the standard residential default. Mix grade (PSI) determines compressive strength and feeds the auto-priced cost estimate.
Hit Calculate — Get Your Estimate
Instantly see total cubic yards, cubic meters, cubic feet, bag count, total weight in tons, and estimated delivered cost. The order-size widget shows you the round-up number a ready-mix supplier will actually quote.
✅ Formula: yd³ = (L × W × T_in ÷ 12) ÷ 27How the 2026 Pricing & Bag-Yield Numbers Are Built
Every number in this calculator comes from one of three named industry sources, blended to reflect current US ready-mix and bagged-concrete pricing. Here's what's under the hood — and where the data is weaker than the headlines suggest.
Primary data sources:
• NRMCA (National Ready Mixed Concrete Association) — quarterly Industry Data Survey covering ~2,000 ready-mix producers across the US. Strength: authoritative per-cubic-yard wholesale and retail averages. Weakness: regional variance can run ±40%, which a national average cannot capture.
• HomeAdvisor 2026 Concrete Cost Guide — aggregated contractor quotes from 50,000+ residential projects. Strength: real homeowner-facing prices including delivery, short-load fees, and finishing. Weakness: contractor-quoted prices include labour and finishing that DIY pours don't pay for.
• ConcreteNetwork & QUIKRETE technical specs — bag-yield tables (40 lb / 50 lb / 60 lb / 80 lb), PSI ratings, set times, and density values. Strength: manufacturer-verified yield numbers. Weakness: bag yields assume textbook mixing — real-world yield can be 5–10% lower with over-wet mixes.
The cost mapping behind the Mix Grade dropdown: Each PSI grade is mapped to the 2026 national-average delivered price per cubic yard for a standard 3-yard residential order — $140 for 2500 PSI, $155 for 3000, $170 for 3500, $185 for 4000, $210 for 5000. These prices include the concrete itself and standard delivery within 15 miles of the plant. They exclude short-load fees, wait-time charges, pumping costs, and Saturday/after-hours premiums.
Where the data gets thin: Concrete pricing is intensely local — fuel costs, plant proximity, aggregate availability, and union labour rates create real-world variance that no national calculator can fix. In high-cost metros (NYC, SF, Boston) add 25–40% to the displayed cost. In rural areas with a long delivery distance from the nearest plant, add a $4–$6/mile haul fee on top of the per-yard price.
Concrete Volume Conversions & Bag Yields (2026)
The whole industry runs on a handful of conversion constants. Memorising the two main ones — 27 ft³ in a cubic yard, 0.45 ft³ from a 60 lb bag — saves countless hours of back-of-envelope math at the job site.
| Conversion | Multiplier | When You Use It |
|---|---|---|
| Cubic feet → cubic yards | ÷ 27 | Converting calculated volume into the unit ready-mix suppliers quote |
| Cubic yards → cubic meters | × 0.7646 | Working with metric specs or non-US suppliers |
| Cubic feet → cubic meters | × 0.02832 | Direct conversion for international jobs |
| Inches of thickness → feet | ÷ 12 | Almost every slab math problem starts here |
| Cubic yards → pounds (concrete weight) | × 4,050 | Checking trailer ratings, planning subgrade, sizing forms |
| Cubic meters → kilograms (concrete weight) | × 2,400 | Metric weight calculations and load engineering |
The two-step slab formula in plain language: Multiply length (ft) by width (ft) by thickness in inches, divide by 12 to convert the thickness to feet, then divide the whole thing by 27 to convert from cubic feet to cubic yards. A 20 × 10 × 4-inch slab works out as (20 × 10 × 4) ÷ 12 ÷ 27 = 2.47 yd³. Most ready-mix suppliers will round that up to 2.5 yd³ when they quote you.
Bag-Yield Reference (manufacturer-verified)
| Bag Size | Cubic Feet Per Bag | Bags Per Cubic Yard | Best For |
|---|---|---|---|
| 📦 40 lb | 0.30 ft³ | 90 bags | Small repairs, fence-post setting, single sonotube |
| 📦 50 lb | 0.375 ft³ | 72 bags | Mid-size repairs, deck-pier pads, retaining-wall caps |
| 📦 60 lb | 0.45 ft³ | 60 bags | Standard residential DIY — patios, small slabs, footings |
| 📦 80 lb | 0.60 ft³ | 45 bags | Larger DIY pours and contractor work — heavier to lift |
Factors That Affect How Much Concrete You Actually Need
The volume formula gives a clean theoretical number. The real world reliably uses more. Here are the eight variables that move your order size — and what each one costs you if you ignore it.
Recommended Slab Thickness by Use Case (2026 best practice)
| Use Case | Recommended Thickness | Notes |
|---|---|---|
| 🚶 Walkway / Patio | 4 inches | |
| 🏠 Residential Driveway | 4 – 6 inches | |
| 🚗 Garage Floor | 4 – 6 inches | |
| 🛻 Heavy-Vehicle Driveway | 6 – 8 inches | |
| 🏗️ Equipment Pad / Workshop | 6 – 8 inches | |
| 🏢 Structural Footing | 8 – 24 inches | |
| ❄️ Footing Below Frost Line | Per local code (often 36"+) | |
| 📐 Sidewalk / City Spec | 4 inches (check local code) |
Bag Mix vs Ready-Mix Truck vs Pumped Concrete: Which to Use
The right delivery method depends entirely on volume. Below about 1 cubic yard, bagged mix wins. Between 1 and 8 yards, a ready-mix truck is almost always cheapest. Above that, or for hard-to-reach sites, pumped concrete is often worth the premium.
| Method | Cost per yd³ | Min Volume | Why You'd Use It | Best For |
|---|---|---|---|---|
| Bagged (60 lb) | ~$300 effective | 1 bag | Smallest jobs, no truck access, repair work | Patios under 50 ft², fence posts, sonotubes |
| Ready-Mix Truck | $140–$210 | 1 yd³ (with short-load fee) | Cheapest per yard once you're above 1 yd³ | Driveways, slabs, garages, foundations |
| Pumped Ready-Mix | $160–$235 | 3 yd³ typical | Truck can't reach the pour location | Backyard pours, basement floors, hilly lots |
| Volumetric Mixer | $200–$260 | 0.5 yd³ | Pay only for what you use, no short-load fee | Mid-size pours where exact volume is uncertain |
| DIY Tow-Behind Mixer | $320+ effective | n/a | You already own one or it's the only option | Tiny remote pours where delivery is impossible |
How to Order & Pour Concrete: A Phase-by-Phase Roadmap
A good pour is mostly done before the truck arrives. Here are the four phases that separate a clean residential pour from the kind that involves panic phone calls to the dispatcher.
Measure the pour area yourself and run the volume calculation. Get at least three written quotes from local ready-mix suppliers — pricing variance of 20–30% within a 25-mile radius is normal. Confirm what's included: short-load fee threshold, delivery range, wait-time charge per 15 minutes after the truck arrives, Saturday surcharge, and whether the price assumes a chute pour or includes pumping. Pull permits if your jurisdiction requires them.
Dig to your finished thickness plus the gravel base depth (typically 4 inches of compacted gravel under a 4-inch slab). Compact the subgrade with a plate compactor — uneven compaction is the most common cause of cracking. Set forms with kiln-dried 2x4s, level them with a string line, and brace stakes every 3 ft. Lay rebar grid or wire mesh on chairs so it sits in the middle of the slab thickness, not on the ground.
Start early — heat is the enemy of finishing. Have at least three people on hand for anything over 2 yards: one directing the chute, one screeding, one floating. Place concrete from the far corner working back toward the truck so you're never wading through fresh mix. Screed with a straight 2x4 immediately. Bull float once water sheen disappears. Wait until the bleed water evaporates before edging, jointing, and final troweling — pushing finishing too early traps water and weakens the surface.
Concrete hardens through hydration, not drying — keeping it moist is what builds strength. Cover with curing blankets, mist regularly, or use a curing compound for the first 7 days. Walk on it after 24–48 hours. Light foot traffic at day 3. Vehicle traffic at day 7. Full design strength at day 28. In cold weather, use insulating blankets to keep the slab above 50°F for the first 72 hours, or use cold-weather admixtures.
2026 Concrete Cost Breakdown by Project Type
The calculator shows you the cost of the concrete itself. On a real job, the concrete is usually only 40–60% of the total bill. Here's where the rest goes — and the regional and project-type variance that any single national price hides.
| Project Type | Materials Only (DIY) | Materials + Labour | Premium Finish |
|---|---|---|---|
| Patio (100 ft²) | $180–$280 | $700–$1,200 | $1,500–$2,500 |
| Walkway (50 ft²) | $90–$140 | $350–$600 | $750–$1,200 |
| Residential Driveway (600 ft²) | $1,100–$1,700 | $3,500–$5,500 | $7,000–$10,500 |
| 2-Car Garage Floor (484 ft²) | $900–$1,300 | $2,800–$4,200 | $5,500–$8,000 |
| Equipment Pad (50 ft², 6") | $160–$240 | $500–$800 | $1,000–$1,500 |
| Structural Footing (8" thick) | $220–$320/yd³ | $600–$900/yd³ | n/a |
Example Concrete Volume Calculations
Three pours, three different scales — all worked through with verified math so you can sanity-check your own results. All examples assume a 10% waste factor and 60 lb bags.
How to Save Money on Your Concrete Order
Concrete is one of the few residential line items where the pricing is genuinely negotiable — and where smart planning can shave $200–$500 off a typical pour. These six moves are where the savings come from.
Concrete pricing varies more by supplier than most homeowners realise. Two ready-mix plants 10 miles apart can quote 20–30% different prices for the same 3-yard residential order. The difference comes from plant utilisation that week, fuel costs, aggregate sourcing, and how badly the dispatcher wants the truck moving. Getting three quotes is not paranoia — it's the standard play.
The other savings lever is timing. Suppliers run busiest Monday and Tuesday mornings (commercial pours), and slowest mid-week afternoons. A pour scheduled for Wednesday or Thursday morning is often 5–10% cheaper than a Saturday or peak Monday slot. Saturday surcharges of 10–15% are standard at most plants.
Six Concrete Cost-Cutting Moves
When This Calculator Is the Wrong Tool
The rectangular-slab formula is the workhorse of residential concrete math, but it's not universal. Here are four situations where the output will mislead you, and what to use instead.
1. Round columns, sonotubes, and circular footings. The volume of a cylinder is π × (diameter ÷ 2)² × height, not length × width × thickness. Plugging a column's diameter into the Length and Width fields will overestimate volume by about 27%. Use a dedicated round-column calculator, or compute π × r² × h manually and convert ft³ to yd³ by dividing by 27.
2. Stairs, steps, and stepped landings. Stair volume is the sum of a series of triangular wedges plus the slab below — it can't be modelled as a single rectangle. For a 4-step set you'd typically run this calculator once for the slab, then add the wedge math separately (rise × run × width ÷ 2 per step). A stair-specific calculator is much faster and less error-prone.
3. Steeply sloped or graded sites. A slab that follows a slope has variable thickness along its length — thicker at the downhill end where the form holds back more material. Using the nominal thickness underestimates volume by 8–15% on slopes over 3%. Measure thickness at both ends, average them, then add an extra 5% on top of standard waste.
4. Sites with limited truck access or unusual pumping needs. The volume math is identical, but the delivery method changes everything about the cost and logistics. Pumping adds $15–$25/yd³ on top of the ready-mix price. Wheelbarrow pours from a curbside truck cost time, not money, but limit you to roughly 1 yd³ per hour of crew effort.
Where to go instead: For round columns and sonotubes, search for a sonotube or column calculator that uses the cylinder formula. For complex foundations, footings, and structural pours, work with a licensed contractor and the engineer's drawings — they include rebar, waterproofing, and load specs this tool doesn't model. This calculator is built for flat, rectangular residential pours, which covers the majority of DIY and small-contractor work.
Concrete Calculator Terms You'll See On This Page
Quick reference for the acronyms and terminology used throughout this calculator and the residential-concrete industry generally.
- Cubic Yard (yd³)
- The standard US ordering unit for ready-mix concrete. One cubic yard equals 27 cubic feet, weighs about 4,050 lb, and costs $140–$210 delivered in 2026.
- Cubic Meter (m³)
- The standard metric ordering unit. One cubic meter equals 1.308 cubic yards or 35.31 cubic feet, weighs about 2,400 kg, and is the preferred unit outside the US.
- Cubic Foot (ft³)
- The base imperial volume unit for concrete math. Bag yields are listed in ft³ (e.g. a 60 lb bag yields 0.45 ft³). Divide ft³ by 27 to get cubic yards.
- PSI (Pounds per Square Inch)
- Compressive strength rating of cured concrete at 28 days. Standard residential grades: 2500 (footings), 3000 (slabs), 3500–4000 (driveways and structural), 5000+ (specialty).
- Slump
- A measure of concrete's wetness and workability, tested with a slump cone. Typical slabs need a 4–5 inch slump; pumped concrete needs higher (5–6 inches) for flow.
- Aggregate
- The sand, gravel, and crushed stone that makes up roughly 60–75% of concrete by volume. The mix design specifies aggregate size — typically ¾-inch for slabs, ⅜-inch for pumped concrete.
- Rebar
- Steel reinforcement bars laid in a grid inside the slab thickness. Adds tensile strength and prevents cracking from settlement and load.
- Wire Mesh
- Welded wire fabric (typically 6×6 inch grid) used as a lighter alternative to rebar in non-structural slabs. Sits on plastic chairs to position it in the slab's middle.
- Bull Float
- A wide flat tool on a long handle used immediately after screeding to smooth the surface and push aggregate down. The first finishing pass before the bleed water rises.
- Bleed Water
- Water that rises to the surface of fresh concrete as the aggregate settles. Must evaporate before edging and final trowelling — finishing too early traps it and weakens the surface.
- Cold Joint
- A weak seam created when fresh concrete is placed against partially-set concrete (e.g. when a truck runs out mid-pour). Significantly reduces slab strength and durability.
- Cure
- The chemical hydration process by which concrete hardens and gains strength. Concrete cures, it doesn't dry — keeping it moist for 7 days is essential to reaching design strength.
- Set Time
- How long fresh concrete remains workable. Typical mix has a 90-minute working window from plant departure to placement, then begins setting.
- Short-Load Fee
- A surcharge ready-mix suppliers add for orders under their minimum (typically 3–5 yd³). Usually $50–$150 — built into the price-per-yard quote when applicable.
- Volumetric Mixer
- A truck that batches concrete on-site from raw aggregate, cement and water. You pay only for what you use — no short-load fee, but a higher per-yard rate.
- Speakable Schema
- JSON-LD markup that tells voice assistants which DOM section to read aloud as the canonical answer for this page's topic.
Frequently Asked Questions
Every question DIYers and contractors ask about concrete volume, ordering, and pricing — answered directly, clearly, and without the jargon.
How do I calculate how much concrete I need?
Multiply length × width × thickness, with all dimensions in the same unit. For a rectangular slab in imperial: ft × ft × inches ÷ 12 gives cubic feet; divide by 27 for cubic yards. Add 5–15% for waste before ordering. For metric: m × m × (cm ÷ 100) gives cubic meters directly. This calculator does both conversions automatically and adds your chosen waste factor.
How many bags of concrete do I need per cubic yard?
One cubic yard of concrete equals roughly 60 bags of 60 lb mix or 45 bags of 80 lb mix. Standard bag yields: 40 lb bag = 0.30 ft³, 50 lb = 0.375 ft³, 60 lb = 0.45 ft³, 80 lb = 0.60 ft³. Above about 1 cubic yard (roughly 60 bags), ready-mix delivery is almost always cheaper and faster than mixing bags.
How much does a yard of concrete cost in 2026?
In the US, ready-mix concrete delivery typically costs $140–$210 per cubic yard in 2026 depending on PSI rating and region. Standard 3000 PSI mix averages $150–$160 per yard. High-strength 4000–5000 PSI runs $180–$220. Most suppliers add a short-load fee of $50–$150 if you order less than 3–5 yards, plus delivery fees and wait-time charges if the pour takes too long.
How thick should a concrete slab be?
Standard thicknesses depend on the load. Patios and walkways: 4 inches. Residential driveways: 4–6 inches. Garage floors: 4–6 inches with reinforcement. Heavy-vehicle driveways or workshop floors: 6–8 inches. Footings vary by structural load and frost depth; check your local building code. Going thicker than required wastes money; going thinner risks cracking and failure.
What waste factor should I use when ordering concrete?
A 5–10% waste factor is standard. Use 5% for flat, well-formed slabs on level ground; 10% (recommended default) for typical residential pours; 15% for irregular shapes, uneven subgrade, or first-time DIY pours. Running out mid-pour creates a cold joint that weakens the slab — always order slightly more than the math says.
Should I use bagged concrete or ready-mix delivery?
Use bagged concrete for small jobs under about 1 cubic yard — fence posts, small patio repairs, sonotube footings. Use ready-mix delivery for anything larger. Above 1 yard, the cost per cubic yard of bagged mix becomes higher than ready-mix once you factor in the time, the bags themselves, and the rental fee for a mixer. Most ready-mix suppliers have a 3–5 yard minimum or add a short-load fee.
How much does a cubic yard of concrete weigh?
A cubic yard of standard concrete weighs about 4,050 lb (roughly 2 tons). Concrete density is approximately 150 lb per cubic foot, or 2,400 kg per cubic meter. This matters for trailer ratings, subgrade preparation, and form bracing — wet concrete exerts substantial outward pressure that under-built forms cannot hold.
What is the difference between PSI and concrete strength?
PSI (pounds per square inch) measures the compressive strength concrete achieves after 28 days of curing. Common grades: 2500 PSI for footings and basic slabs, 3000 PSI for most residential work (driveways, patios), 3500–4000 PSI for heavy-use slabs and structural elements, 5000+ PSI for specialty and commercial applications. Higher PSI costs more per yard but lasts longer in heavy-load or freeze-thaw environments.
How do I convert cubic feet to cubic yards?
Divide cubic feet by 27 to get cubic yards (since 1 yard = 3 feet, 1 yd³ = 3 × 3 × 3 = 27 ft³). To convert cubic yards to cubic meters, multiply by 0.7646. To convert cubic feet to cubic meters, multiply by 0.0283. Concrete is always ordered by the cubic yard in the US and by the cubic meter in most other countries.
How long does concrete take to cure?
Concrete can be walked on at 24–48 hours, takes light foot traffic at 3 days, supports vehicle traffic at 7 days, and reaches full design strength at 28 days. Final cure depends on temperature, humidity, and the mix design. Cold weather slows curing significantly; below 40°F, concrete needs cold-weather admixtures or heated enclosures to cure properly.
Do I need rebar or wire mesh in my concrete slab?
For slabs 4 inches or thicker, structural reinforcement (rebar grid or welded wire mesh) prevents cracking from settlement and load. Patios and small walkways can use fiber-reinforced mix as a lighter alternative. Driveways, garage floors, and structural pads should use a #3 or #4 rebar grid on 16–18 inch centers. Reinforcement does not appear in this calculator's volume math but adds 8–20% to total project cost.
Why does my concrete order need to be rounded up?
Ready-mix suppliers deliver in 0.25 or 0.5 cubic yard increments, so calculated volumes get rounded up to the next available size. A calculated 2.47 yard pour becomes a 2.5 yard order; a 6.79 yard pour becomes 7 yards. The extra material is built into the waste factor and gives you a margin against form expansion, uneven subgrade, and on-site spillage.
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Enter your slab length, width and thickness — get cubic yards, cubic meters, bag count, total weight, and estimated ready-mix delivery cost in 2026 US prices. All free.
Calculate Concrete — Free Takes 30 seconds · No account needed · 2026 NRMCA & HomeAdvisor pricing