Free construction material calculators, plus who builds them and where the numbers come from.
ConcreteCalcTools is a set of free calculators for the materials a job actually runs on: concrete, gravel, sand, asphalt, drywall, pavers, brick, tile, flooring, roofing and more. Punch in your dimensions, get the volume, the bag count, the tonnage or the board feet, and order the right amount the first time.
The reason the site exists is mundane. Most material math is simple arithmetic that nobody wants to do at the lumber yard with a phone in one hand. Order short and you get a cold joint or a second delivery fee. Order long and you eat the waste. A calculator that gets the yield right pays for itself on the first pour.
ConcreteCalcTools is owned and operated by Chris Terry through Encore Promotional Products, as part of the Encore Editorial network of free tools and reference sites. We are not a supplier, a contractor lead service that you have to register with, or a paywall. The tools are open to anyone, no sign-up.
Every tool uses standard, published formulas and industry yields rather than house rules of thumb. Concrete volume is length times width times thickness, converted to cubic yards by dividing by 27. Bag counts use the manufacturer yields printed on the bag: 0.60 cubic feet per 80 pound bag, 0.45 per 60 pound bag, which works out to 45 or 60 bags per yard. Aggregate tonnage uses a density of roughly 1.4 tons per cubic yard. Mulch and topsoil coverage follow the 324 square feet per inch, per cubic yard figure that university extension offices publish. We check these against primary sources and list them on the page so you can verify the number yourself. The full method, with citations, is on our editorial standards page.
Results are estimates based on typical densities and yields. Real materials vary. Damp sand weighs more than dry sand. Crushed stone settles when you compact it. A rough subgrade swallows concrete in the low spots. That is why most tools here add a waste factor and why we tell you to round up. For anything structural or anything over a yard or two, confirm the final quantity with your supplier or a qualified pro before you order.
The site is free because it carries advertising and a few affiliate links to suppliers like Home Depot and to contractor quote services. If you buy through one of those links we may earn a commission, at no extra cost to you. That never changes the math a calculator gives you, and we do not take payment to fudge a number or recommend a product. The affiliate relationships are disclosed at the bottom of every page.
Jessica Martinez writes the cost and material guides. Chris Terry builds the calculators, owns the site, and reviews every draft against the checks listed on the authors page before it goes live. Nothing publishes on one person's say-so: a bag yield gets traced to the manufacturer's data sheet, a footing depth to the code section, a retail price to a dated store listing, and the trace is named right on the page so you can follow it yourself. Guides also get a second worked example computed by hand, because a formula that only agrees with itself has proven exactly nothing.
Guides carry the date they were last updated. The 2026 slab cost table is rebuilt each year from a re-checked bag price rather than rolled forward with an inflation fudge. Corrections land the same week they are reported, dated on the page. And if a number here ever disagrees with the bag sitting in your cart, the bag wins; tell us through the contact form and we will chase down which source moved.