Solution · Measured from imagery, before the truck rolls
Satellite roof measurement for the roofs you have not driven yet.
Aerial and satellite imagery can tell you a roof's size in squares, how many planes it has and how steep it is, without anyone getting on a ladder. The question worth asking is which roofs deserve that measurement at all, because ordering a report on every house in a subdivision is how a measurement budget disappears.
Roof measurement from imagery is a settled technology. Overhead photography, a building footprint and a pitch estimate are enough to compute roof area within a few percent for a typical residential roof, and the trade has been buying reports on that basis for over a decade. What has changed is not the accuracy. It is the price of asking the question on a house you have no relationship with yet.
A certified measurement report costs money per roof and takes minutes to hours to come back. That is entirely reasonable when you are pricing a job for a homeowner who has already said yes to an inspection. It is unworkable as a prospecting step, because you would be paying to measure two hundred roofs to find the fifteen that need one.
So there are two different jobs hiding under the same phrase. One is 'measure this roof precisely enough to order materials and defend a price.' The other is 'tell me roughly how big this roof is, so I know whether it is worth my morning.' They want different tools, and buying the first when you needed the second is the expensive mistake.
How to measure roofs from satellite imagery
- 1
Draw the area instead of picking an address
Measurement tools start from one address because they assume you already know which house you care about. Start from the area instead: put a polygon around the neighborhood or ZIP you work. Scanning new ground costs nothing and has no size limit, so the first pass can be a whole subdivision rather than a single street.
- 2
Read size, planes and pitch off every roof at once
Every roof in the area comes back with its area in squares, how many planes it has and how steep it is, derived from the building footprint and the pitch read off the imagery. One square is 100 square feet, which is the unit you already estimate in. A complex roof with many planes and a steep pitch costs more to do than its square count alone suggests, which is why plane count sits next to the number rather than behind it.
- 3
Check the date on the picture you measured from
A measurement is only as current as the imagery underneath it. Every roof carries the capture date of the image it was judged from, because aerial imagery in a given area is often years old and sometimes a mosaic of several flights. A roof measured off a 2016 tile may have been replaced since. Street-level imagery is newer than the aerial on roughly 85% of roofs, by about five years, so both dates are shown and the newer picture wins where they disagree.
- 4
Use the size to filter, not to quote
The useful move is filtering: set a minimum square count and drop everything below it, because a 12-square ranch and a 45-square two-storey are different mornings. Pair it with the condition read so you are looking at roofs that are both big enough to matter and worn enough to need doing. What you should not do is put an imagery-derived number in front of a homeowner as a price.
- 5
Order the certified report once someone says yes
When a homeowner agrees to an inspection and you need a number you can defend — for materials, for a contract, for an insurance supplement — that is when a measurement report earns its fee. You are now buying one report for a job you are likely to win, rather than two hundred for jobs that do not exist yet.
Satellite, aerial and drone measurement are not the same thing
The three words get used interchangeably and they describe different sources with different trade-offs. Satellite imagery is what most free and low-cost tools read. It covers effectively everywhere, refreshes on a schedule you do not control, and resolves a roof well enough to compute area and count planes. It struggles with very steep pitches and with roofs under heavy tree canopy. Aerial imagery is flown from aircraft, at much higher resolution than satellite, which is why the paid measurement vendors use it. It is the basis of a report you can hand an adjuster. Coverage is good in populated areas and thin in rural ones, and a given area may not have been re-flown for years. Drone measurement is flown by you, on the day, over one property. It is the most accurate and the most expensive in time, and it requires being there — which makes it an inspection tool rather than a prospecting one. For deciding which roofs to visit, satellite is sufficient and its weakness is not accuracy but currency: you are measuring a picture, and the picture has a date.
What a square count does not tell you
Roof area is the input everyone asks for first and it is rarely the number that decides a job. A 30-square roof in good condition is worth less of your time than a 16-square roof with granule loss in the valleys and a patched section over the garage, because the second one has a reason to be replaced. Plane count and pitch matter for the same reason: they change the labour, not the material. A simple gable at 4/12 and a cut-up hip roof at 9/12 with the same square count are not the same job, and a quote built on area alone will be wrong on one of them. This is why the measurement sits next to the condition read rather than standing alone. The size tells you how big the job is. The condition tells you whether there is a job.
Where EagleView and HOVER are the right purchase
There is no version of this page where an imagery-derived estimate replaces a certified measurement report, and pretending otherwise would waste your money rather than save it. Order the report when the number leaves your building: a contract price, a materials order, an insurance supplement, anything an adjuster or a homeowner will hold you to. Those reports carry a stated accuracy and a document you can produce, and that is precisely what you are paying for. Use a free estimate when the number stays inside your building: which streets to work, which roofs clear your minimum size, which houses to put on Tuesday's route. Nobody outside the company ever sees that number, so it needs to be approximately right rather than defensible. Most shops need both, and the mistake is not choosing the wrong vendor. It is using the expensive one for the cheap job.
FAQ
›How accurate is satellite roof measurement?
For a typical residential roof, area computed from a building footprint and an imagery-derived pitch lands within a few percent, which is fine for deciding whether a roof is worth a visit. It degrades on very steep pitches, heavy tree cover and complex roofs with many small planes. It is not a substitute for a certified measurement report when you need a number you can defend to a homeowner or an adjuster.
›Can I measure a roof from satellite for free?
Roofbird returns roof size in squares, plane count and pitch on every roof in an area you scan, and scanning new ground costs nothing at any size. That is a prospecting estimate rather than a report: it tells you how big the roof is so you can decide whether to go, not what to charge when you get there.
›What is a roofing square?
One square is 100 square feet of roof surface. A typical single-family home is somewhere between 15 and 30 squares. Roof area is always larger than the footprint of the house, because the pitch stretches the surface — which is why a pitch estimate has to be part of any measurement taken from a top-down image.
›Is aerial roof measurement better than satellite?
Aerial imagery is flown from aircraft at higher resolution than satellite, so a measurement taken from it is more precise, and it is what the paid report vendors use. For prospecting the difference rarely changes a decision, and the more important question is how old the image is: a precise measurement of a roof that was replaced last year is still wrong.
›How old is the imagery a roof was measured from?
It varies by area and is often a mosaic of several flights, so one neighborhood can carry images years apart. Every roof shows the capture date of the image it was judged from, and where the ground-level Street View is newer than the overhead tile — which it is on roughly 85% of roofs, by about five years — the newer picture is the one that decides.
Read next
Get squares, planes and pitch on every roof in your area.
Draw your area and scan it for nothing. Every roof comes back with its size, its condition and the date of the picture it was read from. First 10 leads free. No card.
Get started free →