How to estimate a roof
- Measure the roof area and divide by 100 to get squares. Use aerial measurement reports or measure on site; note the pitch, because steep roofs take longer and need more safety equipment.
- Add a waste factor — usually 10% for simple roofs and 15% or more for roofs with many valleys, hips and dormers.
- Price the tear-off per square and per layer.
- List the materials you'll install: shingles or metal, underlayment, ice and water shield, drip edge, flashing, vents.
- Set an allowance for decking: a number of sheets included, and a price for each extra sheet.
- Add permit, dumpster and clean-up.
- Set a "valid until" date — material prices change.
Example roofing estimate
| Line item | Qty | Rate | Amount |
|---|---|---|---|
| Tear-off – 1 layer of asphalt shingles (squares) | 24 | $85.00 | $2,040.00 |
| Architectural shingles, 30-year, installed (squares, incl. 12% waste) | 27 | $340.00 | $9,180.00 |
| Synthetic underlayment, ice & water shield, drip edge | 1 | $1,480.00 | $1,480.00 |
| Flashing, pipe boots and ridge vent | 1 | $890.00 | $890.00 |
| Decking replacement allowance – 4 sheets (extra sheets $78 each) | 4 | $78.00 | $312.00 |
| Permit, dumpster and clean-up | 1 | $925.00 | $925.00 |
| Total | $14,827.00 |
Good, better, best
Homeowners like choices. Many roofers present three options — for example standard 3-tab, architectural and impact-resistant shingles — with the price of each. You can make the main estimate with your recommended option and list the others in the notes, or download it as a Word file and add a short comparison.
Decking: say it up front
You can't see the decking until the old roof is off. A line like "Decking replacement allowance – 4 sheets (extra sheets $78 each)" sets expectations, avoids arguments, and lets you bill the real number on the final invoice.
From estimate to invoice
When the job's finished, click Convert to invoice. Your estimate becomes a roofing invoice with the same lines — just change the quantities to what you actually used, and enter the deposit under Amount already paid.
Frequently asked questions
How long should a roofing estimate be valid?
Thirty days is common. During busy seasons or when material prices are rising, some roofers use 15 days.
Should I include insurance claim details?
For storm-damage work, match your estimate to the adjuster's scope as closely as you can and note the claim number in the notes or the PO field.
Do I charge for estimates?
Most roofers give free estimates for replacements. Some charge for detailed inspections or reports and credit the fee if the customer goes ahead.
Can the homeowner sign the estimate?
Download the PDF and ask them to sign and return it, or download the Word file and add a signature line. For larger jobs, use a written contract as well.