Editorial policy

Nail the Math is a small, independent site. Nobody pays us to recommend a product, and the calculators are free with no sign-up. Here is how a page gets made.

1. Sources first

Every number comes from a source we can point to: manufacturer data sheets and bag labels, the International Energy Conservation Code and International Residential Code, the paving industry's installation standards (CMHA, formerly ICPI), and US government data from the Department of Energy, Pacific Northwest National Laboratory, ENERGY STAR and the Census Bureau. Sources are listed on How we calculate or on the page that uses them. Where sources disagree in a way that changes the answer, we note it. When we can't find a reliable source, we leave the number out rather than guess.

2. Tested math

Each calculator's formulas are covered by automated tests that check them against hand calculations. On every calculator page, the worked examples, quick answers and size tables are generated from that same tested code, so the text can't drift from the calculator.

3. Writing and review

Pages are drafted with AI writing and research tools. Nothing goes live on that basis alone. Every page passes:

• an automated style check for vague, padded or repetitive writing,
• a review by a separate AI editor, set up to read the page as a skeptical DIYer and check each claim against the source data,
• a browser test on desktop and phone,
• and approval by the site owner before it is published.

4. Updates and corrections

Codes, products and prices change. Each page shows when it was last reviewed, and the change log lists what changed and when. If you spot an error, email hello@nailthemath.com with the page and what's wrong. We correct confirmed errors and note each fix in the change log.

5. Advertising

The site may show ads to cover its costs. Ads never decide what we recommend, and we label anything sponsored.