Roof pitch from satellite imagery
Last updated: August 8, 2026
Roof Border measures the pitch of every roof face from satellite data and reports each one in x/12 notation — not one average pitch applied to the whole building, but 6/12 on this face, 8/12 on that one, 13/12 on the steep section. No ladder, no pitch gauge, no guessing from the ground.
Why one average pitch is not enough
Pitch is a multiplier on the whole quote. A footprint of 1,800 sq ft becomes 2,012 sq ft of roof at 6/12, and 2,653 sq ft at 13/12. That is 32 % more material and labour from a single number.
| Pitch | Angle | Multiplier | 1,800 sq ft footprint becomes |
|---|---|---|---|
| 4/12 | 18.4° | 1.054 | 1,897 sq ft |
| 6/12 | 26.6° | 1.118 | 2,012 sq ft |
| 8/12 | 33.7° | 1.202 | 2,164 sq ft |
| 10/12 | 39.8° | 1.302 | 2,344 sq ft |
| 12/12 | 45.0° | 1.414 | 2,545 sq ft |
| 13/12 | 47.3° | 1.474 | 2,653 sq ft |
Real houses rarely have one pitch. A main body at 8/12 with a porch at 4/12 and dormers at 13/12 is ordinary. Apply the main pitch to everything and every low section is overbilled while every steep section is underbilled — and the steep sections are exactly where the labour is.
What you get, face by face
Click the building and each roof face comes back separately. A real measurement, from a house in Deux-Montagnes, Quebec:
| Face | Pitch | Area |
|---|---|---|
| 1 | 13/12 | 531 sq ft |
| 2 | 8/12 | 290 sq ft |
| 3 | 8/12 | 270 sq ft |
| 4 | 7/12 | 252 sq ft |
| 5 | 13/12 | 232 sq ft |
| 6 | 13/12 | 204 sq ft |
| 7 | 6/12 | 190 sq ft |
Seven faces, four different pitches, on one ordinary house. A single average would have been wrong on every one of them.
Steep roofs are not rounded down
Pitches are reported up to 18/12. Steeper faces are where tools that cap their scale quietly lose you money: a 13/12 face reported as 12/12 costs you 4 % of that section, and steep sections carry the highest labour rate on the job.
Verify it yourself in ten seconds
Every measurement has a Check pitch in 3D button that opens the property in a tilted satellite view. At 47° a 13/12 is unmistakable next to a 6/12 porch. You do not have to take the number on faith — and you should not.
The honest test is a roof you already know. Measure a property you have quoted by hand and compare face by face. A first $10 deposit includes two extra measurements precisely so this costs you nothing.
On the phone in your truck, or the screen in your office
Roof Border runs in the browser on phone, tablet and desktop. Nothing to install, no app store, no download. The same account, the same measurements, whichever screen you happen to have in your hand.
That matters more than it sounds. Measuring from the truck in front of the house means the customer gets a price before you drive away, instead of that evening — and the contractor who answers first signs more often.
All of the United States, all of Canada
Roof Border covers all fifty US states and every Canadian province and territory. City lots, suburbs and rural properties alike — if the address geocodes, it measures.
The interface and the quotes come in English, Spanish and French. A US account works in English and Spanish, so a Spanish-speaking roofer can measure in Spanish and hand the customer a quote in English — same roof, measured once. A Canadian account works in French and English.
Frequently asked questions
Can you really get roof pitch from a satellite image?
Yes. The pitch of each roof face is derived from satellite elevation data and reported in x/12 notation, face by face, rather than estimated from the building's footprint or shadow.
Is the pitch given for the whole roof or per face?
Per face. Each roof face is listed with its own pitch and its own area, so a house with a 4/12 porch and 13/12 dormers is priced accordingly instead of averaged.
How steep a roof can it measure?
Pitches are reported up to 18/12. Faces steeper than 12/12 are common on dormers, turrets and older Quebec rooflines, and they are not rounded down.
How do I know the pitch is right?
Each measurement includes a Check pitch in 3D link that opens the property in a tilted satellite view, and the per-face breakdown lets you compare against a roof you already measured by hand.
Do I need to climb on the roof at all?
Not to quote it. The measurement returns area and pitch for every face from the satellite. Climbing remains a safety and inspection decision, not a measuring one.
Does it work on a phone?
Yes — phone, tablet and desktop, in the browser, with nothing to install. Most contractors measure from the truck in front of the property.
Where does it work?
All fifty US states and every Canadian province and territory. The interface and the quotes are available in English, Spanish and French.