Free quote checker
Contractor Bid Comparison Calculator
Compare up to three home improvement quotes before you sign. The calculator normalizes cost per square foot, spots lowball bids, checks allowance and deposit risk, and gives you the questions to ask before accepting a contractor estimate.
Quick answer
The middle bid is usually the anchor; the lowest bid needs proof.
Treat any quote more than 15% below the middle bid, above 14% allowances, above 35% deposit, or below 6/10 scope detail as a follow-up item before signing. The right contractor is the bid with the clearest scope, not automatically the lowest number.
Middle bid
$28,500
Bid spread
28%
Lowest bid
$23,900
Highest bid
$31,800
Contractor A
$28,500
$63
0/100
46%
9%
- -scope and pricing look comparatively balanced
Contractor B
$23,900
$53
92/100
41%
21%
- -priced more than 15% below the middle bid
- -large allowances can hide future change orders
- -deposit is above 35% of the contract
- -scope detail score is low
Contractor C
$31,800
$71
0/100
47%
6%
- -scope and pricing look comparatively balanced
Best bid to investigate first: Contractor A
This is not an automatic winner. It is the quote with the lowest current risk score after comparing price, scope, allowances, deposit, schedule and warranty. Ask the questions below before signing.
Questions to ask before accepting a bid
- - What exact materials, model numbers, finishes and quantities are included?
- - Which allowances can become change orders, and at what markup?
- - Is demolition, haul-away, permit handling, cleanup and inspection time included?
- - What payment schedule is tied to completed work, not just calendar dates?
- - What labor warranty and manufacturer warranty are documented in writing?
When the lowest bid is risky
A bid that is far below the middle quote can still be legitimate, but only if the contractor has the same scope, materials, permit assumptions, insurance, schedule, warranty and cleanup obligations as the other bidders.
If the low quote depends on vague allowances, a large upfront deposit, missing permit language, or a short warranty, treat the spread as a negotiation signal rather than a bargain.
Contractor Bid Comparison FAQ
How do I compare contractor bids fairly?
Normalize every quote to the same scope, material grade, quantity, allowance list, permit responsibility, cleanup, warranty, payment schedule and exclusions. Then compare the middle bid, cost per square foot, allowance share, deposit risk and scope detail instead of choosing the lowest total alone.
When is the lowest contractor bid a red flag?
A low bid is risky when it is more than 15% below the middle quote, depends on vague allowances, asks for a large upfront deposit, skips permit language, has a short warranty, or omits demolition, disposal, prep work, cleanup or inspection time.
What should I ask before signing a renovation contract?
Ask for exact product lines, quantities, model numbers, allowance caps, change-order markup, permit and inspection responsibility, payment milestones, warranty terms, license and insurance proof, start date, finish date and written exclusions.
Should I use a calculator before requesting contractor quotes?
Yes. Use the closest HammerIO calculator first so the quote request has measurable scope. For example, use the roofing calculator for roof squares, the garage calculator for slab and framing assumptions, and the home improvement cost calculator for the first budget range.