The most useful message you can send us is a correction. If a number on this site is wrong, we want to fix it quickly.
Reporting a calculation error
Please include the page, the specific figure you think is wrong, and — if you have one — the manufacturer spec or published standard that contradicts it. That last part is what lets us verify and fix a figure the same day rather than adding it to a queue.
Before you write about a result looking wrong: check the coverage or yield figure printed on the product you actually bought. Bag yields and box coverage vary between manufacturers, and our assumptions are all published so you can see exactly what we used.
What we can't help with
We can't design your project, size structural members, tell you what your local code requires, or estimate labour costs for your area. Those need a licensed professional who can see the site. We're a material estimating tool, and we'd rather say so than guess.
Send us a message
We read everything. Corrections get priority.