Inverters & equipment, 45 tools

Get your inverter, strings, and wiring right

Your panels are only half the system. These tools size the inverter, lay out your strings, check your MPPT windows, and confirm your wire gauge and transfer switch, so the equipment behind the panels matches what you're actually installing.

Start here

The tool most people run first

Solar inverter size calculator Inverter size from your array's DC capacity. The starting point for every other tool on this page.

Inverter sizing

Match the inverter to your array

Solar inverter size calculator Inverter oversizing calculator Inverter undersizing risk calculator Hybrid inverter sizing calculator Off grid inverter sizing calculator Grid tie inverter sizing calculator Inverter count for large array calculator Inverter sizing for future battery addition Quick inverter size estimator

Inverter type and performance

Compare inverter types before you buy

Microinverter vs string inverter output tool Central inverter vs string inverter cost tool Three phase vs single phase inverter tool Inverter efficiency loss calculator Inverter efficiency curve comparison tool Inverter clipping loss estimator Inverter continuous vs peak rating calculator Surge capacity calculator Inverter noise and heat derate calculator Inverter monitoring data comparison tool Inverter lifespan estimator Inverter warranty value calculator Inverter replacement cost estimator

Power optimizers and MPPT

Optimizer and MPPT planning

Power optimizer vs microinverter comparison Power optimizer sizing calculator MPPT count vs array layout calculator MPPT voltage window calculator Rapid shutdown compliance cost estimator

String design

Lay out your strings correctly

String sizing tool String length voltage calculator String length temperature derate calculator Max panels per string calculator Min panels per string calculator Parallel strings current calculator Combiner box sizing calculator

Wiring and cable loss

Size the wire, not just the equipment

Wire gauge sizing calculator Voltage drop calculator Conduit fill calculator DC cable loss calculator AC cable loss calculator

Switches and startup loads

Transfer switches, disconnects, and big startup loads

Transfer switch sizing calculator Automatic transfer switch cost estimator Disconnect switch sizing tool Inverter sizing for well pump startup Inverter sizing for HVAC startup Inverter sizing for motor loads

Questions

Frequently asked

Inverter size is based on your array's total DC wattage and a target DC-to-AC ratio, usually between 1.1 and 1.3. The solar inverter size calculator converts your panel count and wattage into a recommended inverter size directly. Your battery choice changes the answer too, which the battery inverter pairing size calculator works out from your pack and loads.

It depends on your panel's voltage rating, your inverter's MPPT voltage window, and the coldest temperature your site sees, since panel voltage rises in cold weather. The max panels per string calculator and temperature derate calculator handle this together. The Department of Energy's inverter basics guide covers the same voltage and MPPT limits from the equipment side.

Microinverters handle shading and panel-level mismatch better and add resilience if one panel underperforms, while string inverters usually cost less upfront for a simple, unshaded roof. See the microinverter vs string inverter tool for a side by side output comparison. Shading is what usually decides it, and the dormer and obstruction loss calculator puts a number on what your roof actually loses.

Wire gauge depends on the current it carries, the run length, and how much voltage drop you can accept, usually kept under 2 to 3%. The wire gauge sizing calculator and voltage drop calculator work together to size this correctly. The Department of Energy's photovoltaic system design basics cover the wiring and layout rules behind these numbers.