Concrete Calculator
Concrete volume equals length × width × depth (in feet) divided by 27. A 4-inch-thick 10 × 12 ft patio slab needs 1.48 cubic yards of concrete, or roughly 1.63 cubic yards with a 10% waste factor. This multi-mode calculator returns cubic yards, bag count, and a 2026 cost range for slabs, footings, columns, walls, steps, and tube forms.
- Expert Reviewed
- Updated April 2026
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Patio, floor, or driveway
Measure the longest dimension
Measure perpendicular dimension
Standard slabs: 4–6 in
5% rectangular pour · 10% typical DIY · 15% complex shapes
80 lb yields 0.60 cu ft per bag
You need
1.63 cubic yards
1.246 m³ · 40 cubic feet · clean volume 1.48 cu yd + 10% waste
Order (ready-mix)
1.75 cu yd
Rounded to nearest 0.25 yd
Or bags (80 lb)
74 bags
Waste factor included
Estimated cost
$204–$285
2026 ready-mix, delivery not included
Short-load fee may apply. Most ready-mix plants charge $40–$60 per cubic yard on orders below 8 cu yd. See the cost section below for the break-even rule.
Formula: V = L × W × D ÷ 27 (ACI 211.1). Cost: RSMeans 2026.
Six Pour Types
Slab, footing, column, wall, step, and tube form — one calculator.
2026 RSMeans Cost
National ready-mix range plus short-load fee flag under 8 cu yd.
PE-Verified Formula
ACI 211.1 volume formula, reviewed by Alex Rivera, PE.
Section 01
How to calculate concrete volume
Concrete volume equals length × width × depth, all measured in feet, divided by 27. The result is cubic yards. For a 4-inch-thick 10 × 10 ft slab: (10 × 10 × 0.333) ÷ 27 = 1.23 cubic yards. Add 5–10% for waste before ordering.
The concrete volume formula
Concrete (Wikipedia: Concrete; ACI definition: CT-22) is a composite construction material made from cement, sand, aggregate, and water. It is sold by the cubic yard in the United States. The volume formula cited below is sourced to ACI 211.1 (Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete) and applies to every rectangular pour — slabs, footings, and walls.
Depth-to-feet conversion
Slabs are specified in inches; the formula takes depth in feet. Divide inches by 12 or use the reference values below.
| Depth (inches) | Depth (feet) |
|---|---|
| 4" | 0.333 ft |
| 6" | 0.500 ft |
| 8" | 0.667 ft |
| 12" | 1.000 ft |
Footing volume formula
Rectangular footings use the same formula as slabs: V = Length × Width × Depth ÷ 27. For multiple identical footings, multiply the single-footing volume by the count. Footing depth must equal or exceed the local frost line per IRC R403.1, which varies by IECC climate zone.
Column and tube form volume
Round columns and Sonotube pier forms use the cylinder formula: V = π × (diameter ÷ 2)² × height ÷ 27. A 12-inch diameter Sonotube at 48 inches deep (a common deck pier footing) holds 3.14159 × 0.25 × 4 ÷ 27 = 0.116 cubic yards per column. For a 6-pier deck, that totals 0.70 cubic yards — order a full cubic yard to absorb overfill and 5% waste.
Section 02
Worked example — 10 × 12 ft patio at 4 inches thick
A 10 × 12 ft concrete patio at 4 inches thick is one of the most common residential pours and a useful reference scenario. Walking through the full calculation end-to-end shows exactly how waste factor, ordering round-up, and bag counts interact.
Inputs: L = 10 ft, W = 12 ft, D = 4 in = 0.333 ft
Step 1. Vcu ft = 10 × 12 × 0.333 = 39.96 cu ft
Step 2. Vcu yd = 39.96 ÷ 27 = 1.48 cu yd (clean)
Step 3. + 10% waste: 1.48 × 1.10 = 1.63 cu yd
Step 4. Round up to the nearest 0.25 yd: order 1.75 cu yd
Bag equivalent (80 lb): ⌈44 cu ft ÷ 0.60⌉ = 74 bags
Section 03
How many bags of concrete do I need?
One cubic yard of concrete requires 45 bags of 80-pound mix, 60 bags of 60-pound mix, or 90 bags of 40-pound mix. For a 10 × 10 ft slab at 4 inches, that is 56 bags of 80-pound mix including a 10% waste factor. The yield numbers come from manufacturer product data (QUIKRETE, Sakrete) and are consistent across major brands.
Bag yield reference
| Bag size | Yield (cu ft) | Yield (cu yd) | Bags per cubic yard |
|---|---|---|---|
| 80 lb | 0.60 cu ft | 0.022 cu yd | 45 bags |
| 60 lb | 0.45 cu ft | 0.017 cu yd | 60 bags |
| 40 lb | 0.30 cu ft | 0.011 cu yd | 90 bags |
Bags vs. ready-mix — when to switch
The decision between bags and ready-mix comes down to volume, crew size, and whether a short-load fee will apply. The thresholds below come from field practice, not theory: a two-person crew can mix about 1 cubic yard of bag concrete per hour with a power mixer. Beyond 1.5–2 cubic yards, mixing time begins to exceed the cost savings.
| Volume needed | Recommendation | Reasoning |
|---|---|---|
| Under 0.5 cu yd (≤ 23 bags of 80 lb) | Bags | Truck is not cost-effective at this volume. |
| 0.5–1.5 cu yd (23–68 bags) | Bags viable | Weigh crew size and mixing time against delivery price. |
| 1.5–2 cu yd (68–90 bags) | Decision point | Compare total cost; a short-load fee is likely on ready-mix. |
| 2–8 cu yd | Ready-mix (short load) | Short-load fee applies; $40–$60 per yd premium. |
| 8+ cu yd | Ready-mix (full truck) | No short-load fee; most economical option. |
Threshold source: NRMCA short-load convention and field averages for residential crews.
Section 04
What PSI concrete do I need?
Residential concrete typically requires 3,000 psi for slabs, patios, and footings. Driveways in freeze-thaw climates require 4,000 psi air-entrained concrete per ACI 318. The psi rating measures compressive strength at 28 days of curing and is the single most important specification you give the plant.
| Application | Minimum PSI | Recommended PSI | Code reference |
|---|---|---|---|
| Residential patio | 2,500 psi | 3,000 psi | ACI 318 |
| Sidewalk / walkway | 3,000 psi | 3,000 psi | IRC R506 |
| Garage floor slab | 3,500 psi | 3,500 psi | ACI 302.1R |
| Driveway (no freeze-thaw) | 3,000 psi | 3,500 psi | ACI 330R |
| Driveway (freeze-thaw climate) | 4,000 psi air-entrained | 4,000 psi | IRC R403.1 |
| Residential footing | 2,500 psi | 3,000 psi | IRC R402.2 |
| Structural slab (load-bearing) | 3,000 psi | 4,000 psi | ACI 318-19 |
Order the psi that matches your application. Ordering higher-psi concrete than required costs more without improving performance for residential work.
Air-entrained concrete — when to specify it
Air-entrained concrete (ASTM C260) contains microscopic air bubbles that absorb expansion pressure from freeze-thaw cycles. Specify air-entrained concrete for any exterior horizontal surface in IECC climate zones 4 through 8 — most of the northern United States. Target air content: 5–7% by volume for 3/4-inch maximum aggregate per ACI 318.
Practitioner note · Alex Rivera, PE
Building inspectors in freeze-thaw jurisdictions regularly flag non-air-entrained concrete on residential driveways. On a 4,000-psi driveway pour in Denver, I specify 5.5–7.5% air content on the delivery ticket and keep the plant's QC sheet in the permit file. When a homeowner orders a generic "4,000 mix" without calling out air, the plant can legally deliver non-entrained concrete — and the surface spalls after the first winter.
Reinforcement selection follows the same code logic. For rebar size and spacing in slabs and footings, use the dedicated Rebar Calculator — task-extension link in the related calculators section below.
Scope note: this page provides estimating guidance reviewed by our PE and CCM authors for residential and light-commercial work. For load-bearing structural design, permit-grade calculations, or soil-bearing-capacity analysis, a licensed structural engineer of record should review the project.
Section 05
Placement temperature — hot and cold weather rules
Concrete should not be placed when ambient temperature is below 40°F (4°C) or above 90°F (32°C) without protective measures. Placement outside this range changes hydration chemistry and produces weaker concrete. Both ACI 305R (hot weather) and ACI 306R (cold weather) define specific admixture and curing requirements.
Cold weather · ACI 306R
Below 40°F, use heated mix water, insulating blankets, or accelerating admixtures (calcium chloride, non-chloride accelerators) to keep concrete temperature above 50°F for the first 72 hours. Never place concrete on frozen ground.
Hot weather · ACI 305R
Above 90°F, cool aggregates with shade and sprinklers, substitute ice for part of the mix water, schedule pours during early morning, and apply curing compound or wet burlap immediately after finishing to prevent plastic-shrinkage cracking.
Section 06
What does concrete cost in 2026?
Ready-mix concrete costs $125–$175 per cubic yard delivered in 2026, depending on psi rating and region. A short-load fee of $40–$60 per cubic yard applies to orders under 8 cubic yards. Bag concrete costs approximately $5–$7 per 80-pound bag, or roughly $225–$315 per cubic yard equivalent when mixed yourself.
2026 ready-mix cost by US region
| Region | 3,000 PSI | 4,000 PSI (air-entrained) |
|---|---|---|
| Southeast (FL, GA, AL) | $125–$145 / cu yd | $145–$165 / cu yd |
| Midwest (OH, IN, IL) | $135–$155 / cu yd | $155–$175 / cu yd |
| Southwest (TX, AZ, NM) | $140–$160 / cu yd | $160–$180 / cu yd |
| Northeast (NY, MA, PA) | $155–$180 / cu yd | $175–$200 / cu yd |
| West Coast (CA, WA, OR) | $165–$195 / cu yd | $185–$220 / cu yd |
Source: RSMeans 2026 Construction Cost Data. Prices include batching and delivery to site; exclude labor, forming, finishing, and reinforcement. Last verified: April 2026.
Pricing inside each region swings with local fuel costs and plant competition. Always request two quotes before ordering. For full project cost including labor, forming, and finishing, use the Concrete Cost Calculator.
Section 07
Short-load fee explained
A short-load fee is a premium charged when you order less than a full ready-mix truckload — typically 8 or 9 cubic yards. The surcharge is $40–$60 per cubic yard below the minimum, so a 5-yard order from a plant with an 8-yard minimum costs 3 × $50 = $150 extra. Avoid the fee by consolidating pours, ordering the full minimum, or switching to bags for projects under 2 cubic yards.
Example — 5 yd order, 8 yd minimum, $50/yd fee:
Deficit = 8 − 5 = 3 cubic yards
Short-load fee = 3 × $50 = $150 added to invoice
Effective cost per yard jumps from $150 to $180 — a 20% premium that changes the bag-versus-ready-mix math.
Section 08
Cement Calculator (Concrete Calculator)
Cement and concrete are not the same material. Cement is a binding powder — one ingredient in concrete. Concrete is the finished composite material: cement, sand, coarse aggregate, and water mixed in specific proportions. A "cement calculator" and a "concrete calculator" calculate the same thing.
Cement is Portland cement (ASTM C150) — a fine gray powder made from limestone, clay, and iron ore. Concrete contains cement, sand (fine aggregate), gravel or crushed stone (coarse aggregate), and water. The common 1:2:3 mix ratio means 1 part cement to 2 parts sand to 3 parts aggregate by weight. The terms cement and concrete are frequently swapped in casual usage; this calculator works for both search queries.
If you arrived here searching for "cement calculator," you are in the right place. Enter your dimensions in the calculator above to get cubic yards, bag count, and cost.
Section 09
Methodology and sources
Every number on this page is tied to a governing standard or a verifiable industry dataset. The volume formula, bag yields, psi recommendations, placement temperatures, and cost ranges are all sourced below. Cost data is refreshed quarterly; the formula and code citations are stable across 2025–2026.
Standards and references cited on this page
Reviews: volume calculators · 38 calculators reviewed
Alex Rivera is a Licensed Professional Engineer (PE) with 18 years of structural and civil engineering experience. He holds PE licenses in California (#C-89412) and Texas (#P.E.-98765). He previously served as Engineer of Record on 250+ residential foundation designs at Thornton Tomasetti. At CalcSummit, he writes and personally reviews every structural, concrete, rebar, deck, and framing calculator against current IRC and ACI 318 standards.
Full profile →Published April 2026 · Last reviewed April 2026 · Next cost-data review July 2026. Cost section co-reviewed by Sarah Kim, CPE. Field practicality reviewed by Marcus Johnson, CCM.
Section 10