Enter Your Details to Start. Instant Results.

Enter your UK postcode, roof pitch, estimated system size and the electricity rate you pay. The solar panel calculator will quickly work out everything you need to see if installing solar panels might be a good idea. It uses local irradiance data and current 2026 installation prices.

Your Details

Used to estimate solar irradiance for your area

Capacity 4.0 kWp
1 kWp 12 kWp
£ Estimated Cost
£0
£0/kWp installed
Payback Period
0 yrs
Until system pays for itself
Annual Generation
0 kWh
Per year
CO₂ Saved Annually
0 kg
Equivalent to X trees

Annual Savings Breakdown

Self-consumption savings £0
SEG export income £0
£ Total Annual Savings £0

System Specifications

  • Number of panels0
  • Roof area required0 m²
  • Optimal angle efficiency0%
  • Expected lifespan25+ years
  • Warranty (typical)25 years

Lifetime Benefits (25 years)

  • Total savings£0
  • Total CO₂ avoided0 tonnes
  • Return on investment0%
  • Equivalent miles not driven0

Monthly Generation Profile

Disclaimer: These estimates are based on typical UK conditions and average assumptions. Actual performance depends on specific site conditions, shading, panel orientation, and installation quality. Always obtain quotes from MCS-certified installers for accurate pricing. SEG rates vary by supplier. Energy prices may change.

What the Results Mean

Installation Cost

We use accurate estimated 2026 install prices to give a quick ballpark figure of how much you should expect to pay for the system size of interest. Check out our solar panel costs page for a more detailed picture of pricing.

Annual Savings

Solar panel savings come from two sources: the SEG (Smart Export Guarantee), which is energy suppliers buying your surplus electricity, and second, how much you use yourself (which replaces electricity bills you’d otherwise pay).

Payback Period

You’ll see an estimated number of years the system will take to pay for itself, after that it’s pure profit. Solar panel systems can last 15 years longer than their breakeven point. That’s a decade and a half of free electricity.

CO₂ Reduction

The solar panel calculator calculates your carbon savings using the current UK grid carbon intensity of 0.207 kg CO₂ per kWh. A 5 kW solar panel system can save over a tonne of CO₂ per year.

Homes That Get the Best Results

South-Facing Roofs

Even if your roof doesn’t face south, you can still generate substantial energy. East- and west-facing roofs generate up to 85%.

Avoid Shading

Use our free solar panel shade calculator to see how much of an impact a tree, chimney or building will have on your output.

Size Matters

A 1 kW system eats up a lot of budget with scaffolding, labour and other install costs, so the cost per installed kW is much higher than a 4 kW system. If you plan on expanding your energy use in the next 5-10 years (like adding an EV), it’s best to plan for that now.

Battery Storage

Adding a solar battery can increase the amount of energy you use from your solar panels from 40% to 85% (meaning less is exported).

Please share our free solar panel calculator, which gives you instant estimations of installation costs, CO₂, how many solar panels you might need, solar generation by month, your payback period, lifetime benefits, and how much you can earn from the SEG.