What should you check in a contractor bid before signing?

You should check the line-item arithmetic versus the stated total, scope normalization, allowance amounts, contractor license status, and whether labor and material rates match the project market.

Guide

Contractor Bid Review Before You Sign

Q: How do you find math errors in a contractor estimate?

Add every line item in the bid and compare the sum to the stated contract total. A gap with no explanation in the bid is a math error or an unlabeled overhead charge.

Q: How do you spot missing scope in a renovation estimate?

Compare the bid scope against a full list of expected project tasks. Common missing items include demo, debris disposal, permit fees, electrical rough-in, plumbing rough-in, and finish-work labor.

Most renovation cost problems are visible in the bid before you sign. If you know where to look. This guide covers what to check, how to find math errors, how to spot missing scope, and when to bring in a licensed GC for a professional review.

TL;DR. 5-step contractor bid review

Add every line item and compare the sum to the stated contract total.
Separate included work from excluded work and allowances so you can compare bids on the same scope.
Check every allowance amount against a realistic range for the market.
Verify the contractor license number is active with no open complaints.
Compare labor and material rates to ZIP-level norms for the project location.

Start with a Bid Review

What should you check in a contractor bid?

A thorough contractor bid review covers five areas. Each can reveal a different category of problem before you commit to a renovation contract.

1Arithmetic. Sum every line item yourself. Compare it to the stated contract total. Any unexplained gap. Whether $2,000 or $60,000. Warrants a written question before signing.
2Scope completeness. Check that the bid covers all expected phases: demo, rough work, permits, inspections, finish work, and cleanup. Missing a phase means a change order after you have already committed.
3Allowance language. Every allowance is a placeholder for an unknown cost. If an allowance is too low for the market, the actual cost will come back to you as a change order. Broad "general allowance" language is a red flag. See common bid red flags.
4License status. Confirm the license number is listed in the bid and verify it in the relevant state database. An unlicensed contractor performing regulated work creates permit and insurance exposure.
5Market pricing. Labor and material rates vary by ZIP code. A bid with rates significantly above or below the local norm is worth questioning. Well above may mean padding. Well below may mean mismatched scope or a contractor planning to substitute materials.

For a printable version of this review process, see the full contractor bid review checklist. Or upload your bid and have a licensed GC run it for you.

How do you find math errors in a contractor estimate?

The most direct method is to create a simple spreadsheet with every line item from the bid. Description, unit, quantity, unit price, and extended price. Total the extended price column. Compare that total to the contractor's stated contract total.

A gap between these two numbers is a math error or an unlabeled overhead charge. Either way, it requires an explanation in writing before you sign.

Common sources of math errors in contractor bids:

1Subtotals for each trade that do not add up to the page total.
2Line items where the unit price times the quantity does not match the extended price.
3A contract total that is higher than all line items combined, with no "overhead and profit" or similar line to account for the difference.
4Duplicate line items in different sections that double-bill the same scope.

A Bid Defense Memo runs this check against every line in the bid and reports the dollar exposure of any unexplained gap.

How do I know if my contractor estimate is overpriced?

Three signals that a contractor estimate may be overpriced — and one that is often missed:

1Line-item rates above ZIP-level norms. Labor and material costs vary by market. If quoted rates are well above what comparable projects cost in your ZIP, that gap needs an explanation — upgraded spec, unusual site conditions, or padding.
2Vague or inflated allowances. A $20,000 "general allowance" for a project where itemized scope would total $8,000 is a pricing problem, not a scope problem. The allowance is doing work the line items should be doing.
3Math that does not close. A contract total higher than the sum of line items — with no overhead-and-profit line — suggests the total was set first and the line items filled in to approximate it.
4The missed one: scope that was not priced. Sometimes a bid is overpriced because work was double-counted. The same demo scope on page one and page two at full price each. Normalization catches this.

A Bid Defense Memo flags each of these specifically, with the dollar exposure attached. For a broader guide on spotting overpriced estimates, see how to know if your contractor estimate is overpriced.

How do you spot missing scope in a renovation estimate?

Compare the bid's scope list against what the project physically requires. For a gut renovation, the following items should appear explicitly or be acknowledged as excluded:

Demolition and debris removal
Permit fees (building, electrical, plumbing, mechanical)
Structural work and inspections
Electrical rough-in and service upgrade (if required)
Plumbing rough-in and drain relocations
HVAC rough-in, equipment, and ducting
Insulation
Drywall and plaster
Tile, flooring, and finish carpentry labor
Fixture and appliance installation labor
Painting. Prep and finish
Final inspections and certificate of occupancy fees
Site protection and cleanup

Any item missing from the bid without an explicit exclusion note is a potential change order. If you see exclusions, ask the contractor who is responsible for those items and whether the cost has been accounted for elsewhere.

How do you compare multiple contractor bids fairly?

You cannot compare bids fairly until they are on the same scope. This is called scope normalization. The process of adjusting each bid to reflect the same set of included work so the final numbers are actually comparable.

A practical approach:

1Create a master scope list covering every item the project requires.
2For each bid, mark each scope item as included, excluded, or covered by an allowance.
3Add a market estimate for each excluded item to each bid's stated total.
4Adjust allowances up or down to a realistic market figure.
5Compare the normalized totals, not the stated totals.

In the LA example on the CostCheckGPT homepage, the lowest-stated bid ($79,800) normalized to $97,800–$107,800. Making it the most expensive of the three once scope was equalized.

When should a licensed GC review the bid?

A self-review using the checklist above catches obvious math errors and missing line items. But a licensed GC review adds:

1ZIP-level labor and material rate calibration based on active market knowledge, not just list prices.
2Allowance adequacy assessment. Whether the dollar amounts are realistic for the stated material grades and project conditions.
3Permit assumption review. Which permits are required, who pulls them, and whether the bid accounts for them.
4Trade-scope coverage. Whether specialty trades (plumbing, electrical, mechanical) are included or assumed to be owner-supplied.
5A forwardable memo with specific negotiation language you can send to the contractor.

A Bid Defense Memo from CostCheckGPT covers all five. Standard delivery is 12 hours. Cost is $249 per bid. To understand your options before hiring a reviewer, see where to get a contractor bid reviewed by a licensed GC.