We built the solar calculator we wanted to use ourselves.
When we priced solar for our own homes, every calculator we tried wanted a phone number first. Within minutes the calls started. So we built one that shows you everything and asks for nothing.
Four promises
1. You never need to give us your phone number. Not to see results, not to save a plan, not ever.
2. Your plan lives in your link. We don't store addresses or plans on our servers. Shared links hide your exact address unless you choose to show it.
3. Every number shows where it came from. Sunshine from NASA, prices from the U.S. Energy Information Administration, homes from the Census. Our model is checked against PVWatts®, the government's own solar calculator. Read the methodology.
4. No one can pay to change a number. Not an installer, not a manufacturer, not an advertiser.
What we are not
We are not an installer, a lender, a utility or a government agency. Our figures are planning estimates, not a site survey. A licensed installer has to inspect your roof, shade and electrical panel before you sign anything.
Privacy, in one paragraph
We count which features people use, without cookies and without knowing who you are. Address lookups are sent to Mapbox (with OpenStreetMap's Photon service and the U.S. Census Bureau as fallbacks) and are not logged by us. Our usage counts go to PostHog, an analytics service, with a random ID instead of your name, address or email. If you email us, we use your address only to reply.
Contact us
Questions, help with a plan, a number you think is wrong, partnerships or press.
Found a wrong number? Choose Report a data error. We fix confirmed errors and list every correction on the methodology page.
Photo credits
Photographs are from Pexels and used under the Pexels licence. Thank you to the photographers.
- A two-storey suburban house with a row of black solar panels on its roof
- Solar panels on a tiled roof above a hillside neighbourhood
- Looking straight down on rooftops, some covered with solar panels
- Aerial view of a leafy American suburb on a sunny day
- A suburban grid of houses from the air at golden hour
- An installer in a hard hat fastening a solar panel
- A technician working on a roof-mounted solar array
- A bank of electricity meters on the side of a building
- Solar panels on a roof covered by fresh snow
- A single candle burning in a dark room during a power cut
- A man plugging an electric car into a charger in his garage
- A couple going through household bills at the kitchen table
- A couple reading paperwork together at home
- The sun setting behind a line of rooftops
- Morning light over the roofs of a small town
- A new two-storey American house with a garage and a young tree
- A ground-mounted solar array standing in a grassy field
- Close-up of solar panel cells catching warm evening light
- Waterfront homes with palm trees under a blue Florida sky
- A single-storey house under dark storm clouds
- A white family house with snow on the ground in winter sun
- A roofer laying new tiles on a house roof
- A technician checking an outdoor heat pump unit beside a house
- A brick craftsman-style house with a deep front porch under trees
- Rows of circuit breakers in an electrical panel
- A hand carrying a portable power station outdoors
- A countryside farmhouse with solar panels on its roof among green hills
- A woman researching on a laptop at her kitchen table
- An inspector in a safety vest holding a house inspection checklist
- A large tree overhanging the roof of a brick house
- A man signing papers while two people look on