Your Roofing Estimate, Explained

A roofing estimate is a list of decisions the roofer has already made for you: how big the roof is, how much waste to allow, which shingle, what goes under it and what happens if the deck is bad. Two bids for the same roof can be thousands of dollars apart because those decisions differ. Here is how to read each line and what to ask before you sign.

Start with the size: squares and waste

Almost every estimate is priced by the square, which is 100 sq ft of roof surface (not floor area). Look for two numbers:

• Measured squares: the actual roof surface, from a tape measure, a drone or an aerial report. A 2,000 sq ft roof is 20 squares.
• Waste: extra material for cuts at hips, valleys and edges. About 10% is normal for a simple gable, 15% for a hip roof and up to 20% for a cut-up roof with dormers.

If one bid says 23 squares and another says 28 for the same house, ask each roofer for the measured number and the waste they used. You can check the size yourself with the roof area calculator and the waste with the waste factor calculator.

What each line item means

Not every estimate itemizes. A single lump-sum price isn't automatically a bad sign, but you should still get the scope in writing: what is included, which products and what happens if they find rot.

Why two bids for the same roof differ

• Different size or waste. The first thing to compare. See above.
• Different products. A basic architectural shingle and a premium designer line can be far apart in price. So can felt versus synthetic underlayment.
• Different scope. One bid replaces all flashing, drip edge and pipe boots; the other reuses them. One includes ice and water shield in the valleys; the other doesn't.
• The decking assumption. A low bid may include zero sheets of decking, so the real price only shows up mid-job.
• Warranty level. Enhanced manufacturer warranties usually require a certified installer and a full system of the maker's accessories, which costs more.
• Overhead and demand. Insurance, licensing, crew pay and how busy roofers are after a storm all move the price.

For a ballpark of what a fair total looks like for your roof size and material, use the roof replacement cost estimator.

Questions to ask every roofer

1. How many squares did you measure, and what waste factor did you use?
2. Which shingle, underlayment and ice barrier products, by brand and name?
3. How many layers are you removing, and is that in the price?
4. What does decking replacement cost per sheet, and how many sheets are included?
5. Are you replacing drip edge, flashing, pipe boots and vents, or reusing any of them?
6. Who pulls the permit?
7. What warranty do I get: the manufacturer's material warranty, an enhanced system warranty, and your own workmanship warranty? For how many years, and is it in writing?
8. Are you licensed (where your state requires it) and insured for liability and workers' comp? Can I see the certificates?
9. Will you use your own crew or subcontractors, and who is the on-site supervisor?
10. What is the payment schedule, and when is the final payment due?
11. How long will the job take, and what happens if it rains mid-job?

Red flags

• Pressure to sign today, especially after a storm by someone who knocked on your door.
• A large cash deposit up front. Some states cap home-improvement deposits, so check your state's rules.
• An offer to "cover" or waive your insurance deductible. That is insurance fraud in many states, and it puts you at risk too.
• No written scope, or products described only as "30-year shingles."
• No local address, no proof of insurance, or no license where one is required.

Signed at your door? The FTC's Cooling-Off Rule generally gives you three business days to cancel many sales made at your home, and some states give more. See the FTC's explanation for what it covers.

If insurance is paying

An insurance estimate is a line-item list too, usually built in estimating software. Two terms come up often. RCV (replacement cost value) is the cost to replace the roof new. ACV (actual cash value) is that minus depreciation. Many policies pay ACV first and the rest after the work is done. A roofer's bid and the adjuster's estimate can be compared line by line, using the table above. What your policy covers is a question for your insurer, or a licensed professional, not your roofer.

For roofers: write the estimate you'd want to compare

Homeowners usually get two or three bids and compare them on price alone, because that's the only number that lines up. Make yours easy to compare instead. Show the measured squares and waste. Name every product. List decking as a per-sheet price with a stated allowance. Say which metal is new. Put the warranty in writing. An estimate that answers the questions above before they're asked looks more trustworthy than a cheaper lump sum. The shingle calculator and drip edge and ridge cap calculator help with the takeoff.

This guide is general information for comparing roofing estimates. It is not legal, insurance or contracting advice. Rules on licensing, deposits and cancellation vary by state.

Last reviewed 2026-10-10. Results are estimates for planning; confirm quantities with your supplier and requirements with your local building code and the manufacturer's instructions.