About MaterialMath
MaterialMath publishes 14 construction material estimators for contractors, tradespeople and serious DIYers in the United States. Every tool shows the formula it uses, cites the source of every figure, and produces a materials list you can take to the supply yard.
Why these calculators exist
Most material calculators on the web give you a number and nothing else. They hide the formula, hardcode the waste factor, quote a raw volume instead of a bag count, and never say where their coverage figures came from. When the answer is wrong — and it often is, in predictable ways — there is no way to see why.
Everything here is built the other way round. Each tool publishes the arithmetic it uses, a fully worked example with real numbers, the assumptions behind every figure, and an explicit list of what it does not account for. If a calculator here tells you something surprising, you can check its working and decide for yourself.
How the figures are sourced
Every rate, coverage figure and code limit is taken from a published source, cited on the page that uses it, and carries the date it was last verified. Figures are reviewed annually and whenever a code cycle changes.
In practice that means:
- Product figures — bag yields, carton coverage, trowel coverage, bundle counts — come from manufacturer technical data sheets, cross-checked between at least two manufacturers where more than one publishes them.
- Code limits cite the section they come from: IRC 2021 §R311.7 for stairs, IECC 2021 Table R402.1.3 for insulation R-values, ACI 318 for concrete cover, IRC §R905.2 for roofing.
- Material densities come from USGS aggregate data and USDA NRCS guidance, presented as typical air-dry values with the moisture variance stated rather than as single precise numbers.
- Conventions rather than standards — the one-third post embedment rule, the 40-diameter lap splice, the 2R+T stair rule — are labelled as conventions, because that is what they are.
Where a figure is derived rather than looked up, the derivation is published in full. The tile calculator works out grout from joint geometry rather than a coverage chart, and the drywall calculator derives tape length from sheet layout. Both show the algebra.
How the tools are built and verified
The calculation code is separated from the data and from the display. Formulas live in pure functions that know nothing about currencies, units or countries; every rate lives in a versioned data file carrying the date it was verified and the URL it came from; all formatting goes through a single module.
That separation is not architectural fussiness — it is what makes the figures auditable. A rate can be checked and updated without touching a formula, and a formula can be tested without a browser. Every engine has known-good test cases covering worked examples that a tradesperson would recognise as correct.
The worked example on each page is computed at build time by the same code that runs the calculator. The numbers in the article cannot drift away from the numbers in the tool, because they are the same numbers.
Who publishes this
MaterialMath is an independent, third-party operator. It is not a manufacturer, retailer, trade association or government body, and it is not affiliated with, endorsed by, or operated on behalf of any source it cites. Every calculator produces a researched reference estimate — useful for planning, not a final or authoritative verdict.
The site is published under its own name rather than under an individual byline. That is a deliberate choice and it has a cost worth stating plainly: a named author with verifiable credentials is a stronger trust signal, particularly on tools that touch building safety.
Publishing under the brand means the credibility has to come from method instead. Every figure is sourced and dated so you can check it against the original. Every limitation is stated on the page rather than buried. Every tool says where the calculation stops and where a licensed professional has to take over. Corrections are welcomed and applied quickly, and the verification date moves when they are.
If a figure here disagrees with a source you trust, trust the source and tell us.
What these tools are not
They are estimates for planning and budgeting. They are not a substitute for a professional takeoff, an engineered design, or the building code as adopted in your jurisdiction. Several of the tools touch on safety-critical work — stair geometry, deck framing, HVAC sizing, reinforcement — and in every case the page says plainly where the calculation stops.
Code adoption in particular varies enormously. The model codes referenced here are adopted state by state, sometimes county by county, and often years after publication. The figures on this site are the model code figures. Your building department is the authority. Read the full disclaimer.
How the site is funded
MaterialMath is free and has no accounts, no paywall and no email capture. It is funded by display advertising and, where relevant, affiliate links to retailers. Affiliate links are always disclosed where they appear.
Neither ever changes what a calculator tells you. The code that computes results has no knowledge of advertising, and the numbers you get are the same whether you click anything or not.
Privacy
The calculators run entirely in your browser. Your dimensions, prices and project details are never sent to a server, because there is no server to send them to — the whole site is static files. Your last-used inputs are saved in your browser's local storage so the tool remembers them next time, and you can clear that at any time with the Reset button. Full privacy policy.
Corrections
If you find a figure that is wrong, out of date, or contradicted by a source you trust, please say so. Getting a coverage rate wrong costs someone a second trip to the supply yard; getting a code limit wrong costs them an inspection. Both are worth fixing quickly. Get in touch.
Figures across the site last reviewed .