How to Estimate a Roofing Job: Squares, Pitch and Waste
October 26, 2026 · 3 min read
A roofing estimate comes down to one number you have to get right: how many squares (100 sq ft each) of roof you're covering. Everything else — shingles, underlayment, labor, disposal — is priced from it.
Step 1: Measure the footprint
Measure the house footprint including the overhangs. For a simple gable roof, length × width of the roof outline is enough. For example: 50 ft × 40 ft = 2,000 sq ft.
Step 2: Apply the pitch multiplier
A sloped roof has more surface than its footprint. Multiply by the pitch factor:
| Pitch | Multiplier |
|---|---|
| 4/12 | 1.054 |
| 6/12 | 1.118 |
| 8/12 | 1.202 |
| 10/12 | 1.302 |
| 12/12 | 1.414 |
At 6/12: 2,000 × 1.118 = 2,236 sq ft = 22.4 squares.
Step 3: Add waste
Add about 10% for a simple gable and 15% or more for hips, valleys and dormers. 22.4 × 1.10 = 24.6, so order 25 squares (75 bundles at 3 bundles per square).
Step 4: Price it line by line
The rates below are example numbers to show the math. Use your own supplier prices, labor costs and local permit fees.
| Line item | Quantity | Rate | Amount |
|---|---|---|---|
| Tear-off (1 layer) | 22.4 squares | $75/sq | $1,680 |
| Architectural shingles | 25 squares | $120/sq | $3,000 |
| Underlayment + ice & water shield | Allowance | — | $600 |
| Drip edge, flashing, vents | Allowance | — | $750 |
| Install labor | 22.4 squares | $110/sq | $2,464 |
| Dumpster & disposal | 1 | $550 | $550 |
| Permit (allowance) | 1 | $250 | $250 |
| Subtotal | $9,294 | ||
| Overhead & profit (25% markup) | $2,323.50 | ||
| Total | $11,617.50 |
Note that tear-off and install labor are priced on the measured 22.4 squares, while shingles are priced on the 25 squares you actually buy.
Step 5: Spell out what could change
Add a line explaining how rotten decking will be handled — for example, a per-sheet price for any plywood replaced after tear-off. That one sentence prevents most roofing disputes and gives you a clean path to a change order.
Step 6: Set the deposit
Many roofers collect a deposit at signing to cover materials. Check your state's rules on deposit limits before you set a percentage.
Send it before you leave
Once your numbers are set, the fastest way to win the job is to get the proposal in front of the customer while they're still thinking about it. With Quote Commander you can build the line items on site, text or email the proposal, and let the customer sign and pay a deposit from their phone. See how it works for roofers, or read how to set your markup.
Frequently asked questions
How many bundles of shingles are in a square?
Most three-tab and architectural shingles come 3 bundles per square (100 sq ft). Check the wrapper — some heavy designer shingles are 4 or 5 bundles per square.
How much waste should I add to a roof estimate?
About 10% for a simple gable roof and 15% or more for roofs with hips, valleys and dormers.
Do I price labor on the ordered squares or the measured squares?
Price labor on the measured roof area. Waste is material you buy, not roof you install.
Frequently Asked Questions
Most three-tab and architectural shingles come 3 bundles per square (100 sq ft). Check the wrapper — some heavy designer shingles are 4 or 5 bundles per square.
About 10% for a simple gable roof and 15% or more for roofs with hips, valleys and dormers.
Price labor on the measured roof area. Waste is material you buy, not roof you install.
Put the paperwork in one place.
Create proposals, collect signatures, send invoices and keep client records in Quote Commander. New job-management tools are in preview. Solo stays $29/month and Pro $79/month, with annual options.