Solar Panel Calculator UK

The solar panel output calculator below will provide you with an estimate to how much a new solar panel system installed on your home’s roof could potentially reward you in financial terms.

The solar panel calculator is specifically created for homes in the UK and will estimate how much solar PV could save you on your energy bill and how much you may be paid.

The calculator uses the various assumptions, including rates of the Smart Export Guarantee, to determine if installing solar would be worth it in your particular circumstances.

Please bear in mind that the tool should not be used as a guarantee and is providing estimate figures only, the ultimate savings and costs may vary.

The solar cost calculator estimates the potential financial rewards based on the Smart Export Guarantee, first launched in January 2020.

Please also note that Smart Export Tariff’s vary from supplier to supplier and you can see the current comparison of the various different tariffs here.


Please provide details of your property

The potential savings and benefits you will receive from installing a solar array system on your properties roof are determined by a variety of factors including your properties location, the amount of shade it has and the incline and direction the roof faces. 

Therefore, in order to calculate the solar costs and rewards, please answer the questions below: 

What is the slope of your roof? 

Please use the slider below to indicate the incline of your roof. For reference, the average roof slope in the UK is around 30 degrees.


0° is a flat roof and 90° means that you want to install PV panels on a vertical surface such as a wall.

How much shade does your roof recieve?

Use the slider to indicate how much shading you expect to have on your roof where the solar PV system will be installed.

20-60% of sky

What direction is your roof facing? 

Please use the slider below to indicate the direction of the most suitable roof space you have. 

You can then adjust the map to locate your property and modify the compass direction. 

Please adjust slide bar to correct direction

What size solar system are you installing? 

Below you can select the size of the solar PV array you plan on installing. 

Our default system size is a medium system (4kWp) as this is the UK average for domestic properties. 

The average solar electricity systems usually require 10-20m2 of unshaded space. Smaller systems are possible too, but could potentially be less financially rewarding. 

Very large
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Your results

For more information, please read the calculator assumptions.

Potential annual benefit

£(Value Potential annual benefit)

Potential CO2 saving

(Value Potential CO2 saving) kg / year

Potential fuel bill saving

£(Value Potential fuel bill saving) / year

Potential payments from SEG
(at 5 p/kWh)

£(Value Potential payments from SEG) year

Potential lifetime benefit

£(Value Potential lifetime benefit)

Potential lifetime CO2 saving

(Value Potential lifetime CO2 saving) kg

Potential lifetime fuel bill saving

£(Value Potential lifetime fuel bill saving)

Potential lifetime payments from SEG
(at 5 p/kWh)

£(Value Potential lifetime payments from SEG)

Estimated installation costs

£(Value Estimated installation costs)

Estimated lifetime maintenance costs


Potential lifetime net benefit

£(Value Potential lifetime net benefit)

Size of the system

(Value Size of the system) kWp

Energy generated by the panels

(Value Energy generated by the panels) kWh / year

What Next? 

  • We advise you get at least three different quotes from reliable and trusted Solar Installers. 
  • You can also familiarise yourself with the latest Smart Export Guarantee tariffs here

How Much Do Solar Panels Cost? Overview:

In reality, the cost of solar panels depends on a variety of factors, including the following:

  • The type of solar panels you install.
  • The brand of the solar panels.
  • The total number of solar panels you are installing.

Solar PV Array Costs Breakdown:

Please bear in mind that a complete solar panel installation does not simply include the costs of the solar panels themselves, but also includes the following:

Short answer: the average UK cost of a new solar install is somewhere between £3,500 and £7,300.

Related solar guides: