Calculators
Solar Panel ROI Calculator
Calculate solar panel system cost, annual savings, payback period and lifetime return, with panel degradation and rising electricity prices.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Deciding whether to install solar
- Comparing installer quotes
- Sizing a system
- Explaining payback to customers
About this tool
What the Solar Panel ROI Calculator does
A solar system pays for itself through the electricity it produces. Annual production is system size times the yield per kilowatt for your location; savings grow as electricity prices rise and shrink slightly as panels degrade. This calculator follows each year to find the payback and total return.
Formula
- Net cost = kW × 1,000 × cost per watt × (1 − incentives)
- Year savings = production × electricity price × export value share
- Production falls by degradation and price rises by escalation each year
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| System size | 7 kW |
| Installed cost per watt | $2.80 |
| Tax credits and rebates | 0% |
| Annual production per kW | 1,300 kWh |
| Electricity price per kWh | $0.16 |
| Electricity price rise per year | 3% |
| Panel degradation per year | 0.5% |
| Value of exported power vs retail | 100% |
| Years to evaluate | 25 |
| Result | Value |
|---|---|
| Payback period | 11.8 years |
| Net savings over the period | $30,037 |
| Net system cost | $19,600 |
| First-year savings | $1,456 |
| Lifetime return | 153.3% |
| First-year production | 9,100 |
How to read the result
Production per kW varies widely by location, roof angle and shading; installers and online solar maps can estimate it for your roof.
How exported power is credited matters a lot. Where exports earn less than retail, adding a battery or using more power during daylight improves the return.
Related calculators
- Home Energy Audit Calculator: Compare home energy upgrades by cost, annual saving and payback, and see the combined effect of doing them all.
- Electricity Cost Calculator: Calculate daily, monthly and yearly electricity cost and kWh for appliances from watts, hours of use and your price per kWh.
- EV Charging Cost Calculator: Calculate monthly electric vehicle charging cost from mileage, efficiency, home and public charging prices, and compare it with a petrol car.
- Commercial Electricity Bill Calculator: Estimate a commercial electricity bill with energy and demand charges, and calculate the effective rate and load factor.
Browse every calculator in Energy and Utility Calculators, or talk to us about websites for energy and sustainability companies.
More tools and services
- 1031 Exchange Calculator
- 401(k) Contribution Optimizer
- 529 College Savings Calculator
- A/B Test Significance Calculator
- Accessible Ramp Calculator
- Accounts Payable Aging Calculator
If you would rather someone did this properly for you, we offer Web Design Services and Website Development, SEO Services: Search Engine Optimization, AI Automation Agency.
Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
Often somewhere between 6 and 12 years, depending on cost, sunshine, electricity prices and incentives.
Many panels lose around 0.5% of output per year and carry 25-year performance warranties.
Incentives vary by country and change over time; check current programmes where you live.
Free strategy session
Let’s build something worth finding.
Tell us where you want the business to be in twelve months. We will come back with a costed plan, a realistic timeline, and the numbers we expect to move — no obligation, no jargon.
- 30-minute call, no pitch deck
- Fixed-price proposal in 48 hours
- You own everything we build
Talk to a developer
Not a sales team
- Response time
- Within 1 business hour
- Where we work
- UK, USA & the Gulf
- Contracts
- No lock-in, monthly rolling
- Working since
- 2023