Calculator

Tools & Calculators

Compare calculator options for sizing, pricing, and evaluating a solar installation.

Continuously maintained3 min read Focus Solar Editorial Team Reviewed for technical accuracy through the Focus Solar editorial process

Use these calculators to estimate system size, choose supporting equipment, and sanity-check project economics before you request quotes.

Available calculators

Solar System Size Calculator for estimating panel capacity based on your daily energy use.
Battery Sizing Calculator for sizing storage around backup duration and usable capacity.
Inverter Sizing Calculator for matching inverter capacity to array size and expected loads.
Solar ROI Calculator for checking payback period and long-term savings.
Panel Output Estimator for estimating production from panel wattage, sun hours, and losses.
Cable Size Calculator for selecting cable sizes based on voltage drop and current.

How to use this section

Start with the system size calculator if you are still figuring out the scale of your project. If you already know the array size, move on to inverter sizing, battery sizing, and ROI analysis to compare practical options.