Concrete Volume Calculator
Every pour starts the same way: exact volume, a waste margin, then the truck-or-bags decision. Bags cost roughly double per yard but need no delivery minimum, so a footing is a bag job and a driveway is a truck job. This calculator does the takeoff for slabs, continuous footings and round piers, shows the order quantity in yards and in 80-lb and 60-lb bags, and prices the concrete itself — the installed pour is a different estimate, handled by the Concrete Slab calculator.
Published Cost data last reviewed Re-checked quarterly
Each mode shows its own dimensions below.
Longest side of the pour.
Shorter side; a 20 × 20 pad is the classic backyard slab.
4 in. for patios and pads; 5–6 in. under vehicles.
Sakrete says +10%; go 15% on uneven subgrade or odd shapes.
Quantities for all three always appear under the result; this picks what gets priced.
Costs are adjusted for labor and material rates in your state.
Low
$630
Typical
$790
High
$1,070
Prices adjusted for Texaslabor & material costs.
| Cost item | Low | High |
|---|---|---|
| Materials | ||
| Ready-mix delivered — 5.50 yd³ (245 × 80-lb bags if hand-mixed) | $630 | $1,070 |
| Estimated total | $630 | $1,070 |
What this estimate assumes
- Geometry: 20 × 20 ft slab at 4 in. thick = 133.3 cu ft ÷ 27 = 4.94 yd³ exact.
- Waste allowance +10% → plan on 5.43 yd³: 5.50 yd³ if a truck batches it (0.1-yd steps), or 245 × 80-lb / 326 × 60-lb bags hand-mixed.
- Priced at $150/yd delivered — the midpoint of Concrete Network's 2026 $160–$195 national band and HomeGuide's $119–$147 delivered band. Trucks bill short-load premiums under a 3–10 yd minimum.
- Materials takeoff only — forms, reinforcement, site prep, pour & finish labor and pump costs live in the Concrete Slab Cost Calculator.
- Material dollars scale by Texas's materials rate (×0.96); the range is 80%–135% of the computed typical.
Typical cost ranges
| Project | Low | Typical | High |
|---|---|---|---|
| 10 × 10 ft (100 sq ft) (1.40 yd³ · 62 80-lb bags) | $168 | $210 | $284 |
| 12 × 12 ft (144 sq ft) (2.00 yd³ · 88 80-lb bags) | $240 | $300 | $405 |
| 16 × 16 ft (256 sq ft) (3.50 yd³ · 157 80-lb bags) | $420 | $525 | $709 |
| 20 × 20 ft (400 sq ft) (5.50 yd³ · 245 80-lb bags) | $660 | $825 | $1,114 |
| 24 × 24 ft (576 sq ft) (7.90 yd³ · 352 80-lb bags) | $948 | $1,185 | $1,600 |
| 30 × 30 ft (900 sq ft) (12.3 yd³ · 550 80-lb bags) | $1,476 | $1,845 | $2,491 |
| 30 × 40 ft (1,200 sq ft) (16.3 yd³ · 734 80-lb bags) | $1,956 | $2,445 | $3,301 |
| Project | Low | Typical | High |
|---|---|---|---|
| Ready-mix truck — 5.50 yd³ delivered (materials only) | $660 | $825 | $1,114 |
| 80-lb bags — 245 hand-mixed (materials only) | $1,254 | $1,568 | $2,117 |
| 60-lb bags — 326 hand-mixed (materials only) | $1,369 | $1,712 | $2,311 |
| Project | Low | Typical | High |
|---|---|---|---|
| 10 in. dia. × 4 ft pier (deck post) (0.10 yd³ · 4 80-lb bags) | $12 | $15 | $20 |
| 12 in. dia. × 4 ft pier (deck post) (0.20 yd³ · 6 80-lb bags) | $24 | $30 | $41 |
| 16 in. dia. × 4 ft pier (post base) (0.30 yd³ · 11 80-lb bags) | $36 | $45 | $61 |
| Continuous footing — 40 ft × 16 in. × 8 in. (1.50 yd³ · 66 80-lb bags) | $180 | $225 | $304 |
| Continuous footing — 80 ft × 16 in. × 8 in. (2.90 yd³ · 131 80-lb bags) | $348 | $435 | $587 |
Frequently asked questions
How many 80-lb bags of concrete make a cubic yard?
Forty-five. An 80-lb bag yields about 0.60 cu ft (Concrete Network quotes ≈0.022 yd³ per bag), and a cubic yard is 27 cu ft. Sixty-pound bags yield about 0.45 cu ft, so they run 60 bags per yard. The default 5.50 yd³ pour here works out to 245 80-lb bags or 326 60-lb bags.
How much extra concrete should I order for waste?
Add 5–10%: HomeGuide's 2026 guide says 5–10% for waste and spills, Sakrete's calculators say 10%, and Concrete Network's rule of thumb is to budget an extra ¼ in. of thickness (about 6% on a 4-in. slab). Use 15% for rough or uneven subgrades, odd shapes, or jobs you hand-mix in batches. This calculator defaults to 10% and lets you change it.
Is it cheaper to buy bags or order a ready-mix truck?
Bags win under roughly a cubic yard — no delivery minimum, no scheduling, no short-load fee. From about a yard up, delivered ready-mix costs roughly half as much per yard ($150/yd modeled here vs. about $288/yd in 80-lb bags). On the 20×20 example, the truck is about $825 versus $1,568 in bags.
How do I figure concrete for round piers or sonotube forms?
Volume = π × radius² × height. A 12-in. tube 4 ft deep is π × 0.5² × 4 = 0.12 yd³ exact — about 6 80-lb bags with a 10% margin. Depth is set by your frost line and local deck-code minimums (commonly 12 in. minimum below grade), so measure the hole, not the tube's length.
How much does a cubic yard of concrete cost in 2026?
Published 2026 bands differ because one quotes delivered and one quotes the plant: HomeGuide lists $119–$147/yd delivered up to 20 miles, while Concrete Network's 2026 price survey shows $160–$195+ (national average $179.95 in 2025; Chicago $170–$210, Los Angeles $170–$200, Lynchburg VA $150–$180). This calculator models $150/yd delivered — between the two. Your plant quote can still land outside the band for spec reasons: 3,500–4,000 psi and air entrainment for freeze-thaw climates cost a little more than the basic residential mix, and short loads under the 10-yard minimum carry HomeGuide's ~$53/yd premium. Hand-mixed 80-lb bags work out near $290/yd.
How much area does one cubic yard of concrete cover?
At 4 in. thick, 81 sq ft — about a 9 × 9 pad. At 6 in., 54 sq ft; at 3 in., 108 sq ft. Flip it around with the yardage: a 10 × 10 slab at 4 in. is 1.24 yd³ (Concrete Network's own example — 56 bags), which is why anything over a yard of patio quickly becomes a truck job.
Does thickness change the bag math as much as the yardage?
Yes — volume scales linearly with thickness, so the 20×20 slab here needs 5.43 yd³ at 4 in., 6.79 yd³ at 5 in. and 8.15 yd³ at 6 in. Each extra inch is 25% more concrete (and 25% more bags) for the same footprint — about $195 more delivered concrete per inch on this pour. Four inches suits patios and walkways; go five to six under vehicles, where subgrade strength and local code push thicker sections.
Why is this total lower than my concrete contractor's quote?
This is a materials takeoff: concrete only. A poured slab also carries forms and stakes, gravel base and grading, mesh or rebar, pour-and-finish labor, and possibly a pump line — plus ready-mix short-load fees (about +$53/yd on orders under 10 yd, per HomeGuide). For the full installed cost, use the Concrete Slab Cost Calculator.
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Open calculatorHow this estimate is calculated
These notes are written for this tool alone: where its base prices come from, how the low–high window is derived, and what the figure deliberately leaves out.
- Volume is exact geometry: slabs are length × width × thickness ÷ 12 (inches to feet); continuous footings are run × width × depth with the dimensions in inches divided by 144; round columns are π × radius² × height with diameter in inches divided by 24. Cubic feet ÷ 27 = cubic yards.
- The order quantity adds your waste allowance (default 10% — Sakrete's calculator advice; HomeGuide says 5–10%; Concrete Network's rule of thumb is an extra ¼ in. of thickness) and rounds the way you buy: 0.1-yd steps for a ready-mix truck, whole bags by the sack.
- Bag yields are the manufacturers' own: an 80-lb bag ≈ 0.60 cu ft → 45 bags per cubic yard (Concrete Network quotes ≈0.022 yd³ per bag); a 60-lb bag ≈ 0.45 cu ft → 60 bags per yard.
- Prices: ready-mix modeled at $150/yd delivered, the midpoint of HomeGuide's 2026 $119–$147 delivered band and Concrete Network's 2026 $160–$195 national band (2025 average $179.95). The 80-lb sack is modeled at $6.40 against HomeGuide's published $6.29 and Sept 2026 big-box shelf prices. No major guide publishes a 60-lb concrete-mix sack price, so it is interpolated at $5.25 between HomeGuide's 50-lb concrete ($4.49–$4.57) and 60-lb mortar ($5.57) rows.
- This tool prices concrete only — a single materials line that scales with your state's materials multiplier (labor never enters the math). Low/typical/high is 80% / 100% / 135% of the computed cost, reflecting mix-strength, order-size and regional spread.
- Excluded: forms, gravel base and grading, mesh or rebar, pump lines, ready-mix short-load fees (about +$53/yd under a 10-yd order per HomeGuide), finishing labor, demolition and haul-off — all of that is in the Concrete Slab Cost Calculator.
- Data reviewed September 2026 by the FixTally Editorial Team.
Sources
Every cost constant above traces to the publishers listed here — the editorial gate requires at least two independent sources per calculator, each with the month we accessed it. FixTally is not affiliated with any of them.
- Concrete Network — Concrete Calculator (80-lb bag ≈ 0.022 yd³; 10×10 at 4 in. = 1.24 yd³ = 56 bags; margin-of-safety guidance) — accessed 2026-09
- Concrete Network — Concrete Prices 2026 ($160–$195+/yd³ nationwide; $179.95/yd³ 2025 average; regional city ranges) — accessed 2026-09
- HomeGuide — How Much Does Concrete Cost Per Yard? (2026) ($119–$147/yd delivered; short-load +$53/yd; 80-lb sack $6.29; add 5–10% waste) — accessed 2026-09
- Sakrete — Concrete Calculators (“remember to add 10% to your estimates for safety”) — accessed 2026-09
Maintained by the FixTally Editorial Team — each quarter we re-check the cited prices, re-run every calculator’s math, and refresh the review dates shown on these pages.
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