Solar calculators
Every solar decision comes down to three numbers: how big a system you need, what it costs installed, and how many years it takes to pay you back. Use your local sun hours, electricity tariff and installer quote. Currency-aware tools support 95 currencies; the US tax and engineering tools are labelled separately.
Showing 13 calculators
- Local inputs · NEC controller marginRV Solar CalculatorSize an RV solar setup in seconds. Get panel wattage, battery Ah, charge controller and inverter sizing using an NEC 690.8 safety margin.Open calculator
- Worldwide · use your local inputsSolar Power Calculator — kWh, Cost & SavingsEstimate solar system size, installed cost, production and savings using local prices in your currency.Open calculator
- Worldwide · use your local inputsSolar Payback Period & ROI CalculatorEstimate solar payback, ROI and 25-year cash flow in your currency using local installation costs, electricity prices and export rates.Open calculator
- Local grid inputs · EPA comparisonsSolar Panel CO₂ Savings CalculatorEstimate the annual and 25-year CO2 emissions avoided by your PV system, using EPA eGRID 2024 grid emission factors.Open calculator
- US standards · engineering referenceSolar Fuse Size CalculatorEstimate DC fuse size using NEC-based assumptions. A US engineering reference; confirm local electrical requirements.Open calculator
- Worldwide · use your local inputsSolar Panel Size Calculator — Panels from kWhFind system size, panel count and roof area in square metres or feet using your electricity use and local sun hours.Open calculator
- Worldwide · use your local inputsSolar Pool Pump CalculatorEstimate pool pump and solar array size in metric or US units, then calculate savings in your local currency.Open calculator
- Worldwide · use your local inputsSolar Loan CalculatorEstimate your monthly solar loan payment, total interest, and net monthly cost — search your country, price it in 95 currencies, on flat or reducing-balance rates.Open calculator
- US standards · engineering referenceSolar Panel Snow Load CalculatorEstimate panel snow loads using ASCE-based assumptions. A US engineering reference; confirm local structural requirements.Open calculator
- Worldwide · use your local inputsHybrid Solar System CalculatorSize a grid-tied hybrid solar system: PV array kW, battery kWh, hybrid inverter capacity, and annual self-consumption.Open calculator
- United States · tax rulesUS Solar Tax Credit CalculatorUS-only residential solar tax and state incentive estimates. Verify eligibility and installation-date rules.Open calculator
- United States · tax rulesUS Solar ITC CalculatorUS-only business solar investment tax credit estimates. Includes the tax assumptions and eligibility limits of the model.Open calculator
- Worldwide · use your local inputsSolar Feed-in Tariff CalculatorCalculate solar export income and self-consumption savings from your local electricity and feed-in tariff rates in your currency.Open calculator
Run the solar payback period and ROI calculator first. It takes your local rates, your system cost, and your roof's sun hours and returns a break-even year plus a 25-year cash flow. If the payback is longer than you want to hold the house, none of the sizing detail matters yet.
Use the how many solar panels calculator to convert your annual kWh into a panel count, then the solar panel estimate calculator to turn that system size into an installation estimate using your local quote. Together they give you the two figures an installer's quote should broadly agree with.
The US-only solar tax credit and solar ITC calculators cover the residential and business credits separately, because they are different sections of the tax code with different rules. The feed-in tariff calculator values your exported energy under full-retail net metering or a NEM 3.0-style avoided-cost rate.
The fuse size calculator applies the NEC 690.8 continuous-current margin, and the snow load calculator works from ASCE 7 ground snow loads. These are sizing checks, not a substitute for a licensed electrician or structural engineer signing off on the install.