Solar Rater

Solar Rater logo

Solar Rater app for Android devices makes it easy to determine the solar energy potential for any location on Earth, and calculates the appropriate size for a photovoltaic (PV) system at that location. Key features include:

  • Automatic location detection with GPS, Wi-Fi, or cell tower identification
  • Automatic orientation detection measures the azimuth and pitch of solar panels
  • Automatic magnetic declination conversion gives azimuth based on true north
  • Automatic solar radiation determination based on location and orientation (model result)
  • Outputs the appropriate size of a PV system in DC Watts
  • Data can also be entered manually for offsite use
  • Great teaching tool for novices
  • Accurate results for solar energy professionals
  • Outputs environmental benefits (e.g., greenhouse gas emissions, water saved, trees planted)
  • Saves projects and emails results
  • Street address can be automatically detected or used to look up latitude and longitude
  • Calculates space requirements and cash payback period from user input.

Screen Shots


solar power, solar energy, solar calculator, solar app, android solar app, renewable energy, pv, photovoltaic


Results compare favorably with NREL PV Watts

Expertise Required

Basic understanding of solar power


Thousands worldwide


Solar energy professionals and facility managers


Requires the solar panel location and orientation (azimuth and tilt), which can be automatically determined with Androidís built-in GPS and orientation sensors. The location and orientation are then used to query the appropriate solar radiation value from a Web database. Users manually enter the amount of energy used at their location and the associated costs (from utility bills), as well as the system efficiency (including all derating factors; default is 80%) and solar production target (how much energy will be produced from solar as a percentage; default is 100%). With the Pro version users can also enter solar panel details (e.g., wattage and area), utility cost escalator, installed system cost, and available rebates and tax credits.


Outputs the appropriate size for a PV system and environmental benefits including greenhouse gas reductions, water saved, trees planted, and cars eliminated. The Pro version also outputs the number of solar panels, DC and AC array rating, AC energy produced, total area, total cost, average annual energy cost savings, and cash payback period.

Computer Platform

Android devices running v.2.0 or later

Programming Language



ultra portable, easy to use, gives immediate and accurate results, free and low-cost versions available; should be used for quick onsite evaluations by solar professionals and facility managers


We will soon add more features, including the ability to look up specific solar panels and inverters.



Earth Science Agency, LLC


PO Box 2858
Stateline, NV 89449
United States








This app is available in two versions: Solar Rater (free) and Solar Rater Pro ($4.99). Both are available in the Android Market (link below) and can be directly downloaded and installed to all supported Android devices.