I built a free ADU quote checker so California homeowners can compare contractor bids line by line

Allowances and exclusions are where bids that look the same end up thousands apart, so this is a good one to solve.

I tried /compare though, and I could only pick 2 of your preset scenarios. I expected to type in my own two quotes. That's the real moment for a homeowner: two bids on the table and a feeling one of them is hiding something. Right now that part is in the worksheet download, and I think most people won't get that far.

Also, I couldn't see where the numbers come from or when they were checked. Building costs change fast, so that's the first thing I'd want to know before trusting a benchmark against a real bid. I do this on my own tool, a source and date on every number, and it's honestly what people look at first.

Are people actually filling in the worksheet, or mostly just browsing the scenarios?

The line-item format feels most useful when it exposes a decision, not just a difference. I’d be curious whether homeowners care more about the biggest absolute gap or the least certain allowance. I’ve seen comparison tools earn trust when they make the unknowns explicit instead of pretending every estimate is equally solid. Are you collecting which line items cause people to pause or ask a contractor follow-up?

Worth considering whether the homeowner is really the best user for this. A contractor who already itemizes honestly loses bids to whoever buried the same costs in one number, and your tool is the thing that makes that visible. Handing it to that contractor to run on their own quote, so they can show a homeowner what is missing from the cheaper bid, puts it in front of somebody with a commercial reason to open it every week rather than twice in a lifetime. The homeowner side stays free and is what keeps it credible. Frequency is the usual problem with homeowner tools and this one has a version without it.

A useful follow-up metric would be quote-to-decision: after normalizing two bids, did the homeowner request clarification, reject one, or sign? Since allowances can hide uncertainty, tagging each line item with confidence/source and showing a delta view could turn a comparison into a conversation starter with contractors rather than a false-precision score.

The line-item approach seems especially useful because it turns “why is this bid higher?” into a concrete list of questions. I’d consider a simple completeness check for missing allowances, exclusions, and contingency assumptions before showing a comparison—otherwise users may mistake an incomplete quote for a cheap one. The strongest success metric might be whether homeowners go back to a contractor with clearer questions, not just whether they view the scenarios. Are you able to observe that follow-through?

This is such a practical tool. ADU permitting is notoriously opaque and homeowners get completely blind-sided by contractor bids — having a free checker that compares line by line is exactly the kind of transparency the industry needs. Smart to build this as a free tool that earns trust before monetizing.

The categorization step is the part I'd stress-test hardest. Contractor line items are never worded consistently — one bid says "site prep," another says "grading & excavation," a third lumps three of your categories into one "sitework" line. If an unfamiliar label gets silently forced into hard cost / soft cost / contingency, that's a quiet miscategorization that only surfaces when someone tries to reconcile the total back to the invoice. Worth flagging any line that didn't match a known label instead of defaulting it somewhere — an "unmatched, categorize this yourself" bucket beats a confident-looking wrong bucket. That plus the source/date on the benchmark numbers (the other commenter's point) are what would make me trust the comparison over just eyeballing the raw PDFs.

The line-item comparison is useful only if it changes the decision. Have any homeowners found a bid difference they would have missed in the original quotes and changed which contractor they preferred?