Concrete Cost Calculator

How This Calculator Works

Concrete is sold by the cubic yard from ready-mix companies (one truck mixer holds about 9-10 cu yd) or by the 60/80-lb bag from home centers. The choice between bagged and ready-mix is mostly volume: under 1 cu yd is almost always bagged; over 1.5 cu yd is almost always ready-mix delivered. Knowing exactly how many cubic yards you need keeps you from over-ordering (wasted concrete and disposal fees) or under-ordering (a half-finished pour that requires a costly second delivery).

The volume formulas:

Slab volume (cu yd) = L × W × (thickness/12) ÷ 27

Column volume (cu yd) = π × (D/2)² × (H/12) ÷ 27

80-lb bags = cubic yards × 45 (each bag yields ~0.022 cu yd)

A standard 10×10×4″ patio slab is L=10 × W=10 × T=4/12 = 33.3 cu ft, divided by 27 (cubic feet per cubic yard) = 1.23 cu yd. With 10% waste, you'd order 1.4 cu yd. From a ready-mix company at $130/yd, that's ~$180 of concrete. The same pour with 80-lb bags would need 56 bags at ~$5 each = $280 — significantly more expensive for any pour over ~1 cu yd.

Why waste matters. Concrete must be ordered before you can verify the exact volume needed. Subgrade variations (the dirt isn't perfectly level), form expansion under load, and the inevitable spillage typically eat 5-10% of the order. Always add 10% to your calculated volume — running short mid-pour costs $200-500 in short-load fees.

Understanding Your Results

Four numbers anchor the output:

• Total cost — concrete + labor + rebar + forms. Use this to vet contractor bids.
• Cubic yards — the order quantity for ready-mix delivery (round up to next 0.25 yd).
• Cubic feet — the same volume in the unit hardware stores use when selling bagged concrete or sand/gravel.
• 80-lb bags — bag count if you're doing a small DIY pour. Each 80-lb bag yields ~0.022 cu yd.

The breakdown table shows the cost components. For a typical 10×10 patio: concrete ~$180, labor ~$500, rebar ~$50, forms ~$40 = ~$770 total. DIY (set labor to $0) drops to ~$270 in materials. The labor differential is roughly half the project cost.

Bagged vs ready-mix decision: Under 0.5 cu yd: bags are easier (one-person mixing, no truck access required). 0.5-1.5 cu yd: bags are technically possible but exhausting (45-100 bags is a long day of mixing). Over 1.5 cu yd: ready-mix is the only realistic choice. Most ready-mix companies have a 1-yard minimum and charge $100-200 short-load fees below that minimum.

Pump truck need: If the pour is more than 80-100 feet from where the ready-mix truck can park, you'll need a concrete pump truck ($800-1,500 additional). Backyard patios and basement pours often require pumps because the truck can't reach. Factor this in early.

Factors That Affect Concrete Cost

Region and supplier

Concrete pricing varies $90-180/cu yd nationally. Urban metros with high aggregate costs (Bay Area, NYC, Hawaii) hit the top of the range. Rural areas with local aggregate quarries are at the bottom. Get 2-3 quotes — pricing varies even within the same city by supplier.

Mix design (PSI strength)

Standard residential mix: 3,000-3,500 PSI ($110-130/yd). High-strength (4,000+ PSI for driveways and pool decks): $130-150/yd. Fiber-reinforced or fast-set: $150-200/yd. Tell the supplier the application — they'll spec the right mix.

Delivery distance and access

Most ready-mix companies include 25-30 miles in the price. Beyond that, $5-10/yd per additional mile. Difficult truck access (narrow alleys, steep driveways, soft yards) sometimes requires a smaller truck (1-3 yd capacity) at a 20-30% premium.

Short-load fees

Below the supplier's minimum (usually 1 yard), short-load fees of $100-200 apply. If your project is borderline, it's often cheaper to oversize the pour (concrete bench, additional slab) than to pay the short-load fee on a smaller delivery.

Form materials and labor

Wood forms (2×4 or 2×6 lumber): $1/lf of perimeter for the lumber, plus 0.5-1 hour of labor per 10 lf to set them. Reusable steel forms: rented from supply houses for $0.50/lf/day. For one-off pours, wood is standard; for ongoing work (foundation contractors), steel.

Reinforcement (rebar and mesh)

Rebar grid for slabs: $0.50/sqft installed. Welded-wire mesh: $0.25/sqft. Required for any slab thicker than 4″ that will see vehicle traffic or any structural application (foundation, footings, retaining walls). For decorative patios and walkways, mesh is enough.

Finishing technique

Broom finish (most common, slip-resistant): included in standard labor. Trowel finish (smooth interior): +20% labor. Stamped/decorative: +$5-10/sqft above standard. Exposed aggregate: +$3-5/sqft. Stained or scored: +$2-4/sqft per process.

Curing and weather

Concrete must cure at 50°F+ for at least 5 days. Cold weather requires hot-water mix ($10-20/yd premium), blankets, or accelerators. Hot weather requires retarders to prevent flash-set. Cure failures cause cracking and weak slabs — schedule pours in moderate weather when possible.

Subgrade preparation

Below the concrete, you need a compacted base of crushed gravel (4-6″ deep, $0.50-1/sqft). Without it, concrete cracks within 1-2 freeze-thaw cycles. Many DIY pours skip this and fail within a year — it's the single biggest preventable failure mode.

Frequently Asked Questions

Next Steps

Once you've nailed down volume and cost, the natural next steps:

• Deck Cost Calculator — concrete footings are step 1 of any new deck.
• Fence Cost Calculator — concrete sets each post; figure out post count first.
• Landscaping Cost Calculator — patios and walkways are usually part of a broader yard plan.
• Renovation ROI Calculator — see how patios and outdoor concrete recoup at sale.
• DIY vs Pro Costs — concrete is one of the easier DIY savings opportunities.