Roof Size Calculator by Address
Type an address and get the roof measured from map data: footprint, true roof area in square feet, roofing squares and what to order. It's free, there's no sign-up, and nobody climbs a ladder. A price range for each material comes with it.
1. Find your house
2. Check the details
A planning measurement, not a survey. The size comes from a map outline plus the pitch you pick. It is close enough to budget, compare bids and rough out materials. Before you order a full roof, measure on site or use a paid aerial report.
How the roof is measured from an address
- Find the building. The address is matched with OpenStreetMap's Nominatim and the U.S. Census Bureau geocoder, then the tool picks your house from the building outlines in OpenStreetMap. The outline is drawn on screen so you can check it, and you can tap a different building if it picked the garage or the neighbor.
- Measure the footprint. The outline's area and perimeter are calculated on the ground in square feet. Outlines are mostly traced from aerial photos, so they already include much of the eave overhang; a small allowance is added on top.
- Add the slope. A flat outline has no pitch. Multiplying the plan area by the pitch multiplier gives the true sloped area. That is the number roofers mean when they say roof size.
- Convert to squares. Divide by 100 to get roofing squares, then add waste for cuts: about 10% on a gable roof, 15% on a hip roof and 20% on a cut-up roof.
Worked example
Roof square footage from footprint and pitch
If you already know the footprint (including the overhang), read across to your pitch. Not sure of the pitch? Compare photos on the roof pitch examples page.
| Footprint | 3/12 | 4/12 | 5/12 | 6/12 | 7/12 | 8/12 | 9/12 | 10/12 | 12/12 |
|---|---|---|---|---|---|---|---|---|---|
| 1,200 sq ft | 1,237 | 1,265 | 1,300 | 1,342 | 1,389 | 1,442 | 1,500 | 1,562 | 1,697 |
| 1,600 sq ft | 1,649 | 1,687 | 1,733 | 1,789 | 1,852 | 1,923 | 2,000 | 2,083 | 2,263 |
| 2,000 sq ft | 2,062 | 2,108 | 2,167 | 2,236 | 2,315 | 2,404 | 2,500 | 2,603 | 2,828 |
| 2,400 sq ft | 2,474 | 2,530 | 2,600 | 2,683 | 2,778 | 2,884 | 3,000 | 3,124 | 3,394 |
| 3,000 sq ft | 3,092 | 3,162 | 3,250 | 3,354 | 3,473 | 3,606 | 3,750 | 3,905 | 4,243 |
From roof area to what you order
| Roof area | Squares | Gable, +10% waste | Hip, +15% waste |
|---|---|---|---|
| 1,500 sq ft | 15.0 | 16.5 (50 bundles) | 17.2 (52 bundles) |
| 2,000 sq ft | 20.0 | 22.0 (66 bundles) | 23.0 (69 bundles) |
| 2,500 sq ft | 25.0 | 27.5 (83 bundles) | 28.8 (87 bundles) |
| 3,000 sq ft | 30.0 | 33.0 (99 bundles) | 34.5 (104 bundles) |
| 3,500 sq ft | 35.0 | 38.5 (116 bundles) | 40.2 (121 bundles) |
Ridge cap, starter strip, drip edge and underlayment are counted separately: see the shingle calculator, drip edge and ridge cap calculator and underlayment calculator.
Ways to measure a roof, compared
| Method | What you need | Good for | Weak spots |
|---|---|---|---|
| Address lookup (this page) | An address and a pitch guess | Budgets, comparing bids, rough material counts | Pitch is your input; complex roofs and missing map outlines |
| Tape measure on the roof | Ladder, tape, a helper | Exact plane-by-plane numbers | Risky on steep or high roofs |
| Measure the ground and use a calculator | Tape around the house walls | Simple gable or hip roofs | You must add overhangs and porches yourself |
| Paid aerial measurement report | An order with a report provider | Ordering materials, final bids | Costs money per report; turnaround time |
What the map can't see
- Pitch. Going from 4/12 to 8/12 adds about 14% to the roof area, so this is the setting to get right.
- Multiple roof levels. A two-story house with a one-story wing is one outline on the map but two roofs. The total area still works; the pitch may differ between them.
- Porches, additions and townhouses. If part of the house is missing, or several units are mapped as one building, switch to "House footprint I enter" and type your own number.
- Unmapped houses. Some newer subdivisions and rural areas aren't in OpenStreetMap yet. The tool then falls back to living area and stories from your listing or tax record.
For roofers
Need a quick size before you drive out? The same lookup works for any US address. To put it on your own site so homeowners get an instant size and price and you get the lead, see the roof quote widget demo. To turn your measurement into a written estimate, use the free roofing estimate builder.
Sources
Building outlines and house numbers: © OpenStreetMap contributors (ODbL). Address search: Nominatim and the U.S. Census Bureau geocoder. Pitch multipliers are plain geometry. Price ranges use the same 2026 installed-cost figures as the roof replacement cost estimator.
Frequently asked questions
Can I measure my roof by address for free?
Yes. Type the address above: the tool reads your house outline from OpenStreetMap, measures it, and converts it to roof square footage and squares using the pitch you pick. There is no sign-up or fee.
How accurate is a roof measurement from an address?
When the house is mapped well, the footprint is usually within a few percent. The pitch and the overhang are the bigger unknowns, so set those carefully. For ordering a full roof of material, confirm on site or with a paid aerial report.
How do I find the square footage of my roof?
Take the footprint including overhangs, multiply by the pitch multiplier (1.118 for 6/12, 1.202 for 8/12), and that is the roof area. A 2,000 sq ft footprint at 6/12 is about 2,236 sq ft of roof.
How many squares is my roof?
Divide the roof area by 100. A 2,236 sq ft roof is about 22.4 squares, or roughly 24.6 squares to order with 10% waste.
Is roof size the same as my home's square footage?
No. Living area is measured inside the walls on every floor. Roof size is the sloped surface over the top floor plus the garage and overhangs. A two-story house has a much smaller roof than its living area suggests.
Do you save my address?
No. There is no account and we never ask for your name, email or phone. The address is only used to look up the building outline.