Methodology
This page explains exactly how TallyTakeoff's numbers are built and checked, what "reviewed" means when you see it on a page, and what we deliberately don't do. If a calculator's output doesn't match this policy, that's a bug in that calculator — tell us.
How formulas are derived
Every calculator starts from published, checkable numbers, not rounded guesses. Baseline coverage rates and waste factors come from manufacturer installation instructions and the trade references specific to that material — spread-rate charts on paint technical data sheets, tile-coverage tables from installation handbooks, wood flooring manufacturer install guides, and concrete yield tables, depending on the tool.
Each calculator's own Formula and Assumptions sections show the exact numbers used and name the source category for that specific tool — that documentation lives on the tool page itself, not in a PDF you have to go find.
Waste factors default to a conservative, rounded-up figure. Running short on flooring or concrete means a second trip to the store or a cold joint in a slab; running slightly long almost never costs you anything comparable. Where a layout or method changes the realistic waste (diagonal tile versus a straight lay, for example), the calculator asks which one applies instead of using one number for both.
Before a formula ships, it's checked by hand against a worked example with real, round-number measurements — shown on the tool page — to confirm the math produces an answer a person could sanity-check with a tape measure and a calculator.
How price ranges are set and reviewed
Prices shown are national-average retail estimates, not live quotes, not tied to any single retailer's data feed, and not affiliate-linked. They exist to get you from "how much material" to "roughly how much money" in one step.
Every price on every calculator is an editable default. If you know your local supplier's price, overwrite the field before you calculate — the estimate updates immediately, and a share link preserves your numbers, not ours.
Prices are reviewed on a quarterly cadence. The current cycle is shown in the footer of every page and in each calculator's Assumptions section as "Prices reviewed July 2026." Reviewing means re-checking the default price fields against current retail ranges and updating them if the market has moved; it does not mean the formulas themselves changed. Each completed review is logged below.
Where regional cost spread is wide, a calculator shows a range instead of a single false-precision number.
What these tools do not do
- No lead generation. There is no "get quotes from a contractor" form anywhere on this site, and we do not sell your project details to anyone.
- No account, no email capture. Every calculator works with zero sign-up. There's nothing to phish or leak because nothing personal is collected to use the tools.
- No data sale. We use standard, aggregate web analytics (page views, not your inputs). Calculator inputs stay in your browser unless you create a share link — in that case the dimensions and prices you entered (and nothing else; no name, no email, no location) are stored under a random short code so the link can rebuild your estimate for whoever you send it to.
- No professional stamp. Every number here is a planning estimate. It is not a substitute for a contractor's on-site measurement, a structural calculation, or a permit-required engineering review.
Corrections
If a formula, a default price, or a unit conversion looks wrong, that's useful information — send it to us with the tool name and the numbers you used, and we'll check it against the source and correct it if it's wrong.
Who writes this
Every page and calculator on TallyTakeoff is written and maintained by the TallyTakeoff Editorial collectively. We don't publish individual author bios, invented credentials, or testimonials — there is no single "veteran contractor" byline behind any one article. What stands behind each number is the sourcing process described above, which you can check yourself on any calculator's Sources section. Corrections go to hello@tallytakeoff.com.