About Concrete Mix Calc

Concrete Mix Calc is a set of free calculators for people who pour concrete: DIYers sizing a patio, contractors double-checking a quote, and everyone in between who just wants to know how many yards or bags a job takes — right now, on one page, without signing up for anything.

How the estimates work

Every calculator runs the same arithmetic a contractor runs by hand: length × width × thickness for volume, ÷ 27 for cubic yards, bag counts from published bag yields (0.60 ft³ for 80-lb, 0.45 for 60-lb, 0.30 for 40-lb), and weight from the standard wet density of 133 lb/ft³ (2,130 kg/m³). Formulas are printed on each calculator page so you can check any number yourself — no black boxes.

Prices are user-editable, with defaults that reflect typical US market ranges. Material availability, regional pricing and site conditions vary, so treat every result as a planning estimate and confirm final orders with your supplier.

What this site is not

It is not an engineering service. Slab thickness, footing depth, reinforcement and soil decisions belong to your local building code and, where relevant, a licensed engineer. The calculators size the concrete; the code books decide everything else.

The guides

The concrete guides cover the questions around the math — drying and curing times, real cost ranges, bag math and how-to walkthroughs — in plain language, each ending in the calculator it pairs with.

Corrections welcome

Found a number that looks wrong, or a project shape we should support? The contact page is open — factual corrections get fixed fast.