Editorial standards

People use our numbers to order real materials and spend real money. These are the standards every calculator, guide, table and FAQ on Free Concrete Calculator must meet before it is published.

Who creates the content

• Izhar Ahmad Danish (Independent Researcher & Blogger) researches product data, search questions and supplier practice, and writes the guides.
• M Bilal (Technical Reviewer) reviews formulas, worked examples and reference tables before they go live.

Accuracy first

• Numbers are checked against the code. Figures in tables, worked examples and FAQ answers are checked by running the same tested calculation library the calculators use.
• Formulas are tested. The calculation library has automated tests built from hand-worked examples, and they are run before changes are published.
• Assumptions are visible. Each calculator states the density, yield or rounding rule it uses, and our methodology page lists them all.

Sources we use and sources we don't

We cite primary, authoritative sources only:

• Government publications (state departments of transportation, the Federal Highway Administration, USDA and university extension services).
• Standards bodies and industry associations (ASTM International, the American Concrete Institute, NRMCA, PCA).
• Manufacturers' product data sheets for yields, strengths and coverage.

We do not cite other calculator websites, competitors or content farms as sources. If a figure cannot be confirmed from an authoritative source, we leave it out.

What we never do

• Invent statistics, prices, quotes, studies or expert credentials.
• Present national average prices as fact. Prices vary too much by region and season, so cost tools use the prices you enter.
• State building-code requirements as universal. Codes differ by location, so we say when to check with your local building department.
• Let advertisers or brands influence results. We are independent of every brand we mention, and brand names are used only to describe products.

How questions and topics are chosen

We build each page around the questions people actually ask: searches, "people also ask" questions and the sizes people search for (a 10 × 10 slab, a 4 × 4 post, 100 square feet of gravel). Each page covers one job so that pages do not repeat each other; related topics are linked rather than copied.

Use of AI tools

We use AI tools to help with research, drafting and illustration. The illustrations on this site are AI-generated artwork, not photographs. AI is never the source of a number: every figure is computed by our tested calculation library or taken from a cited authoritative source, and a person reviews each page before it is published.

Updates and freshness

Each page shows the date it was last reviewed. We re-check pages when a product data sheet, standard or supplier practice changes, and review cost guidance before the spring building season.

Corrections

If you find an error, contact us with the page address and the numbers you entered. We check every report, fix confirmed errors promptly, update the review date and, for significant corrections, note the change on the page.

Advertising and independence

The site is free and is funded by advertising. Ads are clearly separated from content and are never placed between calculator inputs and results. Advertisers have no say in what we write or calculate.

Last reviewed 2026-10-09.