FREE TOOL
Roof Azimuth Calculator
Find out exactly which way your roof faces. Type your address, find your roof on the satellite photo, then tap the ridge and a second point in the direction the roof slopes down. You'll get the azimuth in degrees from true north, which is the number every solar calculator and installer asks for.
What is roof azimuth?
Azimuth is the compass direction your roof slope faces, measured clockwise from true north. North is 0°, east is 90°, south is 180° and west is 270°. A roof section that slopes down towards the north west sits at around 315°. In Australia the sun tracks through the northern sky, so north facing roof sections collect the most solar energy over a year.
How do I use this calculator?
Type your address and pick it from the list. The map jumps to a satellite photo of your home. Zoom right in on the roof section you're thinking about for panels. Tap the ridge first (the high line at the top of the section) to place the blue dot. A dotted north line appears through it so you can see the angle you're making. Then tap a second point in the direction the roof slopes down to place the red dot; it doesn't need to stop at the gutter, and a longer line is easier to get straight, so go well past it into the yard if you like. Just keep the line square to the gutter. If the arrow points the wrong way, hit Flip 180°. Drag the dots to fine tune, then use Copy link to save or share the result.
Which direction is best for solar panels in Australia?
North is best. East and west are still well worth it: at typical roof tilts they collect roughly 85 to 90% of what a north facing roof does. East favours morning generation and west favours the afternoon, which suits households that use most of their power in the evening. South facing roofs collect the least, roughly 80 to 85% of north, and are usually the last choice when another section is available.
To be honest, direction matters less than most people think. A working west facing system beats a north facing one with a faulty panel every day of the week.
True north or magnetic north?
This calculator measures from true north, because satellite maps are aligned to true north. That's also what solar design tools like PVWatts use. A phone compass reads magnetic north instead, which is out by 2 to 13° depending on where you are in Australia. In Sydney the difference is about 12°; in Perth it's closer to 2°. Measuring off the map avoids the problem entirely.
Common questions
How accurate is this?
Within a degree or two if you zoom right in and place the dots carefully. That's plenty for solar. A few degrees either way changes annual output by well under 1%.
Do you store my address or location?
No. There's no database behind this tool. The address lookup goes to OpenStreetMap's free geocoder and the imagery comes from Esri, the same way any online map works. Solar Buddy doesn't save or see any of it.
Why does my roof look out of date on the map?
Satellite imagery is refreshed every year or two depending on the area, so a new build may not show yet. The tool works on any roof you can see, including an identical neighbouring one down the street.
What azimuth number do I give my installer?
The degrees figure, measured from true north. Anything from about 315° through north to 45° is in the sweet spot for Australian roofs.
Own solar already?
The direction of your roof was locked in the day the house was built. What changes is whether every panel is still pulling its weight. Solar Buddy connects to your inverter, learns how your system should perform and alerts you within 2 hours when a fault appears.