About ConcreteCalc
ConcreteCalc is a free, browser-based concrete calculator designed to help homeowners, DIY enthusiasts, and contractors estimate concrete volume, bags, weight, and cost for a wide range of projects. Our goal is to make concrete estimation simple, accurate, and accessible to everyone — no sign-ups, no fees, and no data collection.
What We Do
We provide a concrete volume calculator that supports five common shapes: rectangular slabs, circular slabs, footings, columns, and steps. The calculator works in both metric (metres, kilograms) and imperial (feet, pounds) units, includes an adjustable waste factor, rebar estimation, and a side-by-side cost comparison of bagged concrete versus ready-mix delivery. Results can be exported as a PDF for your records.
Beyond the calculator, we publish in-depth guides on concrete topics — from understanding volume formulas to choosing between ready-mix and bagged concrete, and from metric calculations to rebar sizing. We also provide real-world project scenarios that walk through complete calculations for common projects like patios, shed foundations, and driveways.
Methodology and Data Sources
Our calculator uses the standard concrete density of 2,400 kg per cubic metre (approximately 4,550 lbs per cubic yard), which is the accepted figure for normal-weight concrete mixes used in residential construction. Bag coverage figures are derived from manufacturer specifications for standard pre-mixed concrete bags available in North America, Europe, and Australia.
Pricing defaults are based on 2025 average retail and delivery prices in the United States. These are estimates only — concrete prices vary significantly by region, supplier, mix design, and delivery distance. We always recommend getting quotes from local suppliers before placing an order.
Rebar calculations use standard bar dimensions and weights per the ASTM A615 specification. Spacing recommendations are based on common residential construction practices but are not structural engineering calculations. For any load-bearing application, consult a licensed structural engineer.
Privacy
All calculations happen entirely in your browser. We do not send your project dimensions, costs, or any personal data to our servers. The only data stored is your most recent calculator inputs, saved to your browser's localStorage so they are available when you return. This data stays on your device and can be cleared at any time through your browser settings.
We use Google Analytics (GA4) to understand aggregate site traffic and Google AdSense to support the site through advertising. Both are subject to your consent preferences. No personal project data is shared with these services.
Disclaimer
ConcreteCalc provides estimates for informational purposes only. Our calculator, guides, and scenarios do not constitute professional engineering, architectural, or construction advice. Always consult qualified professionals for structural projects, verify quantities with your materials supplier, and comply with local building codes and regulations. We accept no liability for decisions made based on our estimates.