Contact
One address for everything: [email protected]. We read every message. Simple questions get a reply within a couple of business days; error reports usually get a reply the same day, because they matter most.
Reporting an error
If a calculator gives a result you believe is wrong, we want to know — we'd rather hear about it three times than not at all. The most useful report includes:
- Which calculator, and which tab or mode you were on.
- The exact inputs you entered, units included.
- The result you got and the result you expected, with your reasoning or source if you have one.
What happens next: we reproduce it, check the formula against its cited references, and either fix it or write back explaining why the number is what it is. Verified fixes ship within days and the review date on the page is updated. Larger corrections — like the change made when the federal energy tax credits expired at the end of 2025 — are noted on the page itself so nobody keeps relying on the old figure.
Requesting a calculator
Tell us what you're trying to work out and what you'd do with the answer. "How many pavers for a 12 × 14 patio with a soldier-course border" is far more useful to us than "a paver calculator." We build the ones with real demand first, and every one is free once it exists.
Embedding a calculator on your site
Contractors, suppliers, and home-improvement blogs are welcome to put any calculator on their own pages at no cost — one line of HTML, no signup, no key. Details are on the embed page. If you need a different default, a specific product's coverage rate, or a size list that matches your inventory, ask; we've made those adjustments for partners before and it usually takes a day.
What we can't help with
We don't give project-specific engineering advice, and we can't tell you whether your particular slab, deck, or electrical panel meets code. For structural, electrical, or gas work, the answer is a licensed local professional and a permit. The calculators will tell you how much material a job takes; they won't tell you whether you should be the one doing it.
Press and partnerships
Same address. We're happy to explain how any calculator works, share the formulas and sources behind a number, or talk about what's being built next.