About BuildCalc

Free material calculators for people who would rather measure twice than drive to the store twice.

What this site is

BuildCalc is a small collection of focused calculators for construction and DIY materials — concrete, paint, mulch, tile, gravel and sod. Each one answers a single question: how much do I buy?

The site is free to use, needs no account, and runs entirely in your browser. Nothing you type is sent anywhere or stored.

How the numbers are built

Every calculator is based on a published constant rather than a guess:

  • Concrete bag yields come from manufacturer specifications: 0.60 cu ft for an 80 lb bag, 0.45 for 60 lb, 0.30 for 40 lb.
  • Paint coverage uses 350 sq ft per gallon, the conservative end of the 350–400 sq ft range manufacturers quote.
  • Gravel density defaults to 1.4 US tons per cubic yard, the standard figure for crushed stone.
  • Material coverage for mulch, tile and sod is stated on the calculator page and can be edited to match the product you are actually buying.

Each tool page prints its formula and a worked example, so you can check the result by hand. If our number and your arithmetic disagree, the printed formula is the arbiter — and we want to hear about it.

What we are not

These calculators produce estimates for planning and shopping. They are not engineering advice, not a substitute for a contractor's takeoff, and not a structural or code-compliance opinion. Local building codes, soil conditions and site access can change the answer. Always confirm quantities against the product label and, for anything structural, against a licensed professional.

How the site is funded

BuildCalc is supported by display advertising. Ads are served by third-party networks, which may use cookies as described in our privacy policy. We do not sell user data, and the calculators work identically whether or not ads load.

Corrections

If a constant is wrong, a formula is off, or a result does not match your real-world experience, send us the details — including the inputs you used and what you expected. Corrections are published with the change, not quietly patched.

Editorial standard

Content is written and reviewed by the BuildCalc team, with figures checked against manufacturer documentation and standard construction references. Pages show the last meaningful revision below.

Last reviewed: October 2026