Editorial policy

Where the numbers come from

Physical constants — bag yields, paint coverage, the 324 square-feet-per-yard-inch identity, aggregate densities — come from manufacturer data sheets and extension-service publications. The page that uses a constant names the source so you can open it yourself. We re-derive each figure from that source rather than copying another calculator, because copied constants are how wrong yields propagate across the internet.

Prices are a different kind of number. They are US national-average estimates, labelled with the month they were set, and they are never a quote. Ready-mix, gravel delivery, and paint all move with region and season. If a figure is a range, we show the range. If confidence is low, we say so. Confirm the current price with the supplier who will actually sell to you.

How the math is checked

Every calculator’s logic lives in a tested function, not in the page template. The tests lock the awkward places: float noise that would round a bag count up an extra bag, waste applied before the round-up rather than after, densities that would otherwise produce Infinity. Most figures printed in a guide or a size page are generated from that same function at build time, so an article cannot quietly disagree with the widget above it.

The constants, rounding rules, waste factors and their sources are written up in how we calculate. If a published answer cannot be re-derived by hand from what is on the page, that is a bug.

What we will not publish

• Engineering advice. These are planning estimates for typical residential conditions. Structural slabs, footings, load-bearing work, and anything that needs a permit need a licensed professional and a local code check.
• Live prices dressed as quotes. We do not scrape retailers. A cost on this site is an estimate with a date, not a cart total.
• Size pages with nothing unique to say. A programmatic URL ships only if it has hand-written context for that size and size-specific computed takeoffs (joints, reinforcement, supplies). If we cannot say something true about a footprint that is not true of its neighbours, we do not add the page. That rule exists because a set of near-identical templates is thin content, and thin content is how this site failed its first advertising review.

Corrections

If a number looks wrong, email us with the page URL, the inputs you used, the figure you saw, and your source if you have one. We re-derive it from the constants. When we are wrong we fix the page, add a regression test so the error cannot return, and bump the “last updated” date rather than silently editing.

Advertising and affiliate links

The site is free. Display ads and, where relevant, affiliate or partner links to retailers and contractor-matching services help pay for it. Two rules:

• Commercial relationships never change a calculation, a recommendation, or the order of options. The concrete calculator will tell you bags lose to a truck above about a cubic yard; the slab cost page will tell you hiring a pro is cheaper than a botched DIY pour. That is the point of being independent of a retailer.
• Affiliate and partner links are disclosed on the page that carries them. If a link has no such disclosure, it is not one.

We do not sell sponsored guides, paid placement inside a calculator, or link insertions into existing articles. Pitches along those lines are declined. See how the site is funded.

Who writes this

BagsAndYards is published by Thomas Empl, working independently — not a contractor network, a retailer, or a lead-generation front. It is not licensed engineering or construction advice, which is exactly why the site sticks to published physical constants and labelled estimates rather than telling you what to pour on your soil. Questions: [email protected].