TrueSizeLumber is a small, independently run reference site. Found a measurement that looks off, or a size that's missing from the chart? That's the most useful thing you can report — accuracy is the whole point of this tool.
If you're reporting a measurement issue, mention the specific page or size and what you think the correct dimension should be, ideally with a source (supplier spec sheet, ANSI/ASME reference, or your own caliper measurement). For everything else — new sizes to add, broken links, advertising or partnership inquiries — a short description is enough to get started.
This is a one-person project run alongside other work, so replies aren't instant, but every message gets read.