Tools in This Collection
Concrete Calculator
Calculate cubic yards of concrete for slabs, footings, and columns
Concrete Block Calculator
Estimate CMU block count for walls in running or stack bond patterns
Concrete Mix Calculator
Get bag counts by mix ratio and strength for site-mixed concrete
Brick Calculator
Calculate brick count and mortar for walls and veneer projects
Rebar Spacing Calculator
Determine rebar count and linear footage for slabs and footings
Wall Framing Calculator
Estimate stud count, plates, and headers for any wall section
Asphalt Calculator
Convert driveway area and depth to tons of hot-mix asphalt
Post Hole Concrete Calculator
Estimate concrete bags per post hole by diameter and depth
Retaining Wall Calculator
Estimate block count, gravel base, and drainage for retaining walls
Plan Your Concrete, Masonry, and Framing Project
Ordering the wrong amount of concrete is one of the most costly mistakes in home improvement. A 10x12 ft slab at 4 inches thick requires 1.48 cubic yards of concrete — most homeowners either estimate by eye or over-order by 30% to be safe. These calculators give you accurate material counts before you contact a ready-mix supplier or load up the truck with bags.
Concrete Volume and Mix Calculations
Start with the Concrete Calculator for any rectangular or cylindrical pour. It converts your dimensions into cubic yards and adds a waste factor — typically 10% for standard pours. For fence posts and deck footings, the Post Hole Concrete Calculator estimates bags per hole based on diameter and depth. A standard 12-inch diameter by 36-inch deep post hole needs about 2 bags of 80-lb concrete. Mixing on site? The Concrete Mix Calculator gives you bag counts by mix ratio and strength. Standard concrete uses a 1:2:3 ratio of cement:sand:gravel. A 4,000 PSI mix for driveways requires a lower water-to-cement ratio than a standard 3,000 PSI walkway mix.
Masonry: Brick, Block, and Retaining Walls
The Concrete Block Calculator handles both running bond and stack bond patterns. Standard 8x8x16-inch CMU blocks cover 1.125 blocks per square foot in running bond. For brick work, the Brick Calculator handles modular, queen, and king brick sizes with mortar joint width — about 6.75 standard bricks per square foot. The Retaining Wall Calculator estimates block count, gravel base, and drainage materials for walls up to 4 feet high.
Rebar and Structural Framing
The Rebar Spacing Calculator determines bar count and total footage for slabs and footings. Standard residential slabs use #4 rebar on 18-inch centers — a 400 sq ft slab needs approximately 44 bars each direction. The Wall Framing Calculator estimates studs, plates, and headers for any wall length. Standard 16-inch on-center framing uses roughly one stud per linear foot plus extras for corners and openings. For driveways, the Asphalt Calculator converts area and depth to tons of hot-mix asphalt — a 2-car driveway at 2-inch compacted depth typically requires 8-12 tons.
Frequently Asked Questions
How accurate is the concrete calculator?
The concrete calculator gives a volume-based estimate accurate to within 2-3% for rectangular pours. Always add a 10% waste factor for standard pours and 15% for complex shapes with curved edges or multiple elevations. Ready-mix is typically sold in 0.5 cubic yard increments, so round up to the next half yard.
How much concrete do I need per fence post?
A standard 4x4 post in a 12-inch diameter by 36-inch deep hole requires approximately 2 bags of 80-lb concrete (about 1 cubic foot). For 6x6 posts or posts in high-wind areas, use a 16-inch diameter hole with 3 bags per post. The Post Hole Concrete Calculator handles any diameter and depth combination.
What is the standard rebar spacing for a concrete slab?
Most residential concrete slabs use #4 rebar (1/2-inch diameter) on 18-inch centers in both directions. For driveways and garage floors subject to heavier loads, reduce to 12-inch centers. Fiber reinforcement can supplement but typically does not replace rebar for structural slabs. Always check local building codes for your specific application.
How many bricks do I need per square foot?
Standard modular bricks (3-5/8" x 2-1/4" x 7-5/8") in a running bond pattern with 3/8-inch mortar joints require approximately 6.75 bricks per square foot of wall face. Add 5-10% waste for cuts around windows, doors, and corners. The Brick Calculator adjusts automatically for queen and king brick sizes.