Concrete Calculators
Calculate concrete volume, mix ratios, bag counts, and material costs for slabs, footings, columns, and walls.
9 calculators available
Rebar Calculator
Calculate how much rebar you need for a concrete slab. Enter slab dimensions and bar spacing to get total linear feet, number of Grid Bars / Lines, and estimated weight.
Open calculator →Concrete Column Calculator
Calculate how much concrete you need for round columns, piers, and sonotubes. Enter diameter, height, and number of columns to get cubic yards, cubic feet, cubic meters, and 80 lb bags.
Open calculator →Concrete Block Calculator
Calculate how many concrete blocks (CMU) you need for any wall. Enter wall length and height to get block count, mortar bags, and wall area — with adjustable waste factor.
Open calculator →Concrete Driveway Calculator
Calculate exactly how much concrete you need for a driveway. Enter length, width, and thickness to get cubic yards, cubic feet, cubic meters, and an optional cost estimate.
Open calculator →Concrete Footing Calculator
Calculate how much concrete you need for rectangular spread footings, strip footings, and pad footings. Enter length, width, depth, and number of footings for exact cubic yards and an optional cost estimate.
Open calculator →Concrete Bags Calculator
Calculate how many bags of concrete you need for slabs, footings, posts, patios, and other projects. Supports 40 lb, 50 lb, 60 lb, and 80 lb bags with adjustable waste factor.
Open calculator →Post Hole Calculator
Calculate concrete, gravel, and excavation volume for fence posts, deck posts, pergola posts, and pole foundations. Accounts for post displacement and gravel base so you order the exact number of bags.
Open calculator →Concrete Slab + Rebar Calculator
Combined slab and rebar calculator. Enter slab dimensions, thickness, and rebar spacing to get concrete volume in cubic yards plus total linear feet of rebar and weight in one step.
Open calculator →Frequently Asked Questions
A 10×10 slab at 4 inches thick requires about 1.23 cubic yards. Add 10% waste and order 1.35 yards — roughly 25 bags of 80 lb mix.
A 10-inch diameter hole 2.5 feet deep takes about 2 bags of 80 lb concrete mix per post. Use the Post Hole Calculator for exact volumes.
For pours over 1 cubic yard, ready-mix is cheaper and more consistent. Under 1 yard, bags are practical. Ready-mix typically costs $125–$175 per cubic yard delivered.
Residential slabs: 4 inches. Driveways: 4–6 inches. Garage floors for heavy vehicles: 5–6 inches. Structural slabs follow engineered specs.
Concrete reaches ~70% strength at 7 days and full design strength at 28 days. Foot traffic is safe after 24–48 hours, vehicles after 7 days.
Concrete is the foundation of nearly every construction project. Getting your quantities right before you pour saves money, prevents mid-job shortages, and eliminates costly over-ordering. Our calculators use the same formulas contractors rely on every day, with built-in waste factors and both imperial and metric support.
Concrete Calculator Tools
Enter length, width, and thickness to get cubic yards, cubic feet, and cubic meters instantly. Works for patios, garage floors, pool decks, and any flat pour.
Open calculator → Concrete Bags CalculatorTells you exactly how many 40, 50, 60, or 80 lb bags you need for hand-mixed jobs. Accounts for yield per bag so you never underorder.
Open calculator → Concrete Footing CalculatorHandles rectangular strip footings and gives you volume for the entire run. The most critical pour in any structure.
Open calculator → Concrete Driveway CalculatorAccounts for standard driveway thickness (4–6 inches) and outputs volume ready to pass to your ready-mix supplier.
Open calculator → Concrete Block CalculatorEnter wall dimensions and block size to get a precise count with mortar joints included.
Open calculator → Post Hole CalculatorConcrete volume for fence posts, deck footings, and sign bases. Enter hole diameter, depth, and post count.
Open calculator → Concrete Slab + Rebar CalculatorGet concrete volume and rebar quantities in one step — cubic yards of concrete plus linear feet, piece count, and weight of rebar for any reinforced slab.
Open calculator →Concrete Cost Reference
Always add 5–10% to your calculated volume for waste, spillage, and subgrade variation.
Concrete Mix Reference
| Strength | Typical Use | Mix Ratio (cement:sand:aggregate) |
|---|---|---|
| 3,000 psi | Residential slabs, sidewalks | 1:2:3 |
| 3,500 psi | Driveways, commercial floors | 1:1.5:3 |
| 4,000 psi | Structural, heavy loads | 1:1.5:2.5 |
Ready-mix suppliers offer these as standard mixes. For bag concrete, follow the bag label for the labeled psi rating.
- Foot traffic: safe after 24–48 hours
- Vehicle traffic: safe after 7 days (~70% strength)
- Full design strength: 28 days
- Avoid heavy loads and freezing temperatures during the first 7 days