What this site is for
QuickJob Calc answers quantity questions for home and garden projects: how much paint, mulch, concrete, tile, decking, or gravel. Enter your dimensions, and each calculator shows the arithmetic rather than hiding it behind a single number.
It is a planning tool, not a substitute for a site visit or engineered drawings. Real ground is uneven, real walls are not square, and real products vary between batches. The calculators give you a defensible starting quantity and the reasoning behind it, so you can adjust for what you find on site.
Where the numbers come from
Coverage rates, bag yields, and waste factors come from three kinds of source: published manufacturer technical data, industry standards and installation guidance, and plain unit definitions. When a published figure is a range, the calculator uses the conservative end, because running short in the middle of a job costs more than a small leftover.
Three constants do most of the work across the site. Interior latex paint is planned at 350 sq ft per gallon, the low end of the 350–400 sq ft range on premium data sheets. An 80 lb bag of concrete mix yields 0.6 cu ft, which is why a cubic yard takes 45 bags. A cubic yard is 27 cubic feet, the conversion that separates bag volumes from bulk orders.
Every constant is listed on the methodology page, next to the assumption it supports.
How a page is checked
Every calculator is code, and every worked example is tested against that code before it ships. If a coverage rate changes, the article fails the test until it is updated. That test is not a formality: it compares the numbers printed on the page with the numbers the calculator actually returns, down to the bag count.
The same rule covers the guide pages. Where a guide publishes a chart, the chart is generated from a data module that a test checks against the calculator. A transcription error in a table fails the build rather than reaching a reader.
How we use AI
Drafts are produced with AI assistance, then checked line by line against the calculator code and published manufacturer data. No page is published with an unverified number. The calculator logic itself is reviewed as code, not prose.
AI is a drafting tool here, not an authority. It is useful for turning a verified formula into readable explanation and for catching gaps in a page's structure. It is not trusted to invent a coverage rate, a code requirement, or a product claim, and anything it produces that cannot be traced to a source is cut.
What we don't publish
Prices are the biggest omission. Material costs swing by region, season, and supplier, and a number that is accurate in one market is misleading in another. The site compares quantities instead.
We also avoid year-locked titles, because a page that says “latest” or a specific year reads as stale within months. We do not claim trade credentials the author does not hold, and we do not make promises about outcomes a calculator cannot control.
Corrections
If a number is wrong, tell us through the contact page. Include the page and, if you have it, the calculation you expected. We aim to correct verified errors within seven days.
A corrected page gets a new review date, and the structured data on the page is updated at the same time so search engines see the change. We would rather fix a page than quietly delete it.
Advertising and affiliate links
Advertising keeps the calculators free. Ads are placed around the content and never inside the result area, and no advertiser sees or influences a calculation. If affiliate links are added in the future, they will be disclosed on the page and will not change which product or quantity the calculator recommends.
Who writes this
J. Mercer is the editorial identity behind the site, working as research and tool development. J. Mercer is the pen name used by the site's editor, who builds each calculator from published manufacturer coverage data and checks every worked example against the code that ships. Not a licensed contractor or engineer — the site says so where it matters.
More about the site and its scope is on the about page, and the assumptions behind every calculator are on the methodology page.