Smart Export Guarantee Calculator
Estimate your UK SEG income from solar generation, export share and the latest supplier export rates, or your own tariff.
Quick answer
Smart Export Guarantee income = annual generation × share exported × tariff rate. A UK system making 4,000 kWh a year that exports half earns 2,000 kWh × 12p = £240 a year on Outgoing Octopus. On an open 3p tariff the same export earns only £60, so the tariff you choose can change SEG income fourfold. Rates are as of October 2026.
How to use the Smart Export Guarantee calculator
- Choose how to set generation. Pick I know my kWh to type a yearly figure, or Estimate from location to work it out from your system size and PVGIS sun data for your town.
- Enter your annual generation. Use the estimate on your MCS certificate, or a full year of generation meter readings. With the location option, enter the system size in kWp and search your town.
- Set the share you export. Without a battery most homes export 50 to 70% of their solar. A battery or a daytime routine lowers that figure.
- Pick an SEG tariff. Choose a supplier rate from the list, or pick Custom rate and type your own pence per kWh. Then check your import rate, which values the solar you keep.
- Read the result. The large number is yearly SEG income. The cards show the monthly average, the kWh exported, the bill saving from self-use and the gain over a 3p tariff.
SEG income formula
Your supplier pays for each kWh your export meter records. The calculator multiplies three numbers.
Where:
- G is annual generation in kWh. In location mode G = kWp × the yearly yield of 1 kWp from PVGIS 5.3 at a south-facing optimal tilt with 14% system losses.
- x is the export share as a decimal and E is exported kWh.
- p is the SEG rate in pence per kWh.
- i is your import rate in pence per kWh. The default 26.32p is the Ofgem price cap average for 1 October to 31 December 2026.
Worked examples
Example 1: 4,000 kWh on Outgoing Octopus
A typical 4 kWp roof makes 4,000 kWh a year and half is exported.
That is £20 a month on average, higher in summer and close to nothing in December. The 2,000 kWh used at home saves 2,000 × 26.32p = £526.40, more than twice the export income.
Example 2: 4.5 kWp in Birmingham
PVGIS gives about 971 kWh per kWp for Birmingham, so generation is 4.5 × 971 = 4,371 kWh. At 50% export and 12p, income is about £262.28 a year. The monthly chart shows that May to August earn roughly three times what November to February do.
Example 3: a battery home on a fixed 13p tariff
A 5,000 kWh system with a battery exports 60%, or 3,000 kWh, on E.ON Next Export Exclusive at 13p. Income is 3,000 × 0.13 = £390.00 a year. On a 3p open tariff it would be £90.00, so switching is worth £300 a year if you are happy to take E.ON Next import.
SEG tariffs and income compared
Rates from supplier websites, checked October 2026. Income assumes 4,000 kWh generated and 50% exported (2,000 kWh).
| Tariff | Rate | Main condition | Yearly income |
|---|---|---|---|
| EDF Export Exclusive | 18p | Solar or battery bought from EDF, 12-month fix | £360.00 |
| E.ON Next Export Premium | 17.5p | Installed by E.ON, 12-month fix | £350.00 |
| OVO SEG Install Exclusive | 15p (up to 20p with battery) | Installed by OVO, OVO import | £300.00 |
| E.ON Next Export Exclusive | 13p | E.ON Next import, 12-month fix | £260.00 |
| EDF Export 12m | 13p | EDF import, 12-month fix | £260.00 |
| Outgoing Octopus | 12p | Octopus import, variable | £240.00 |
| British Gas Export Premium | 12p | British Gas import, up to 15 kWp | £240.00 |
| OVO SEG Beyond Exclusive | 12p | OVO import | £240.00 |
| E.ON Next Flex Export | 6p | Any supplier, variable | £120.00 |
| EDF Export Variable Value | 5.6p | EDF import, variable | £112.00 |
| OVO SEG | 4p | Any supplier | £80.00 |
| EDF and British Gas open SEG | 3p | Any supplier | £60.00 |
Octopus also offers time-based export tariffs, such as Prime Outgoing at 16p from 4pm to 7pm and 9p at other times. Those suit homes with a battery that can discharge in the evening peak.
What affects the result
Tariff choice and supplier tie-ins
Every licensed supplier with an SEG obligation must offer a rate above zero, but the rate is set by the supplier. The best rates usually require you to buy your electricity from the same company, so compare the import tariff too. A high export rate paired with an expensive import rate can leave you worse off.
How much you export
Each kWh you use yourself saves 26.32p at the price cap, while exporting earns 3p to 18p. Using more of your solar is almost always worth more than exporting it. The solar self-consumption calculator estimates your split from usage patterns and battery size.
Location and orientation
Southern England yields around 1,000 kWh per kWp a year and Scotland closer to 850. East or west roofs produce less than south. The solar panel output calculator handles any orientation.
Eligibility
Under the Ofgem SEG rules, solar PV and other small generators up to 5 MW in Great Britain qualify. Suppliers ask for an MCS certificate (or equivalent) and a smart meter that records half-hourly export.
Frequently asked questions
How much can I earn from the Smart Export Guarantee?
Multiply your exported kWh by the tariff rate. A typical 4 kWp home exporting 2,000 kWh a year earns £240 at 12p, £360 at 18p and £60 at 3p. Most homes earn between £60 and £400 a year, depending on system size, tariff and how much solar they use themselves.
What is the best SEG rate in October 2026?
The highest flat rates are tied to installs: EDF Export Exclusive pays 18p and E.ON Next Export Premium 17.5p, each fixed for 12 months. For existing systems, E.ON Next Export Exclusive and EDF Export 12m pay 13p, and Outgoing Octopus pays 12p. Each requires buying electricity from that supplier.
Do I need to switch electricity supplier to get SEG payments?
No. Open tariffs such as E.ON Next Flex Export at 6p, OVO SEG at 4p and EDF or British Gas at 3p are available whatever supplier you use. The higher rates of 12p and above usually require you to take your import supply from the same company.
How do I find my export share without an export meter reading?
Your smart meter’s export register shows exported kWh. Divide that by your generation meter reading for the same period. Without either, use 50 to 60% for a home without a battery that is empty on weekdays, about 40% if someone is home all day, and 20 to 35% with a battery.
Can I get SEG payments for power exported from a battery?
Often yes, but terms vary by supplier. OVO pays up to 20p when it installs both solar and a battery, and EDF Export Exclusive covers solar, battery or both. Suppliers usually ask for a battery schematic and may restrict export of power charged from the grid, so check the tariff terms before you sign.