About QuantityWise

QuantityWise publishes material quantity calculators for renovation and building work, together with the reference data they run on.

What this site is for

Estimating materials is a solved problem for anyone who does it for a living and a genuinely difficult one for everybody else. The arithmetic is not hard; knowing which arithmetic applies is. How much extra tile does a herringbone floor need compared to a straight one? Does new plasterboard change how much paint you buy? Is half a cubic metre of concrete a bag job or a lorry job?

Those questions have real answers that trade estimators use every day, and they are mostly not written down anywhere a homeowner can find them. This site puts them in a calculator, publishes the figures behind it, and shows the working so you can check it rather than trust it.

How the figures are produced

Every number on the site is in one of three categories, and we say which on the page:

• Derived — calculated from geometry, with the formula printed. Grout quantity from tile size and joint width, screw counts from stud spacing, concrete volume from the shape you are pouring. You can check these yourself, and we would like you to.
• Published — manufacturer and standards figures, such as adhesive consumption per trowel notch or the placed yield of a bag of concrete mix. Brands differ, usually by 10–20%, so we use a mid-range value and tell you to check the bag.
• Working estimates — waste factors and practical paint coverage rates. These come from merchant estimating practice and installer guidance rather than a single authority. They are rounded up on purpose: running short costs far more than over-ordering, and the two errors are not symmetrical.

Where we are uncertain, the page says so. Where a figure would be misleading — carpet waste, for instance, which depends entirely on how a room divides into the roll width — we say that a percentage is the wrong tool and explain what to do instead.

What we do not do

• Structural design. Foundations, retaining walls, lintels and anything carrying a building need an engineer. The concrete calculator gives you a volume, not a specification.
• Local regulations. Fixing centres, board specifications, fire ratings and damp-proofing requirements vary by country and by building. Your local rules always take precedence over anything here.
• Product recommendations. We do not review or rank brands, and no manufacturer pays to appear on this site.

Corrections

These pages get better when people who fit this material for a living disagree with them. If a figure does not match your experience on site, or your supplier's data sheet contradicts one of ours, please get in touch. Corrections are noted with a date on the page they affect.

Who publishes this

QuantityWise is published by AdWave USA LLC, Wyoming, United States. Written and maintained by a small team with backgrounds in construction estimating and software. Contact details are on the contact page.

How the site is funded

The calculators are free and there is no account to create. The site is supported by advertising, which is disclosed in the privacy policy. Advertisers have no influence over the figures published here, and no calculator result is affected by any commercial relationship. If that ever changes, it will be stated plainly on the page it affects.

Last updated 2026-09-18.