Home battery sizing tool
Right-size your battery — under-sizing leaves money on the table
This is a free UK calculator. Enter your figures to get an instant, personalised result — no signup, no email capture, no upsell.
Frequently asked questions
What size battery for an average UK home?
10–13kWh hits the sweet spot for a 4-bed without electric heating. Heat pumps and high-mileage EVs push the recommendation higher.
Can I add more later?
Most modular systems (GivEnergy, Pylontech, Solax, Fox) allow stacking. All-in-one units like Powerwall 3 are easier to add as a second unit.
Is bigger always better?
No — the chart in the tool shows diminishing returns past your nightly demand + buffer. Capacity you can't fully cycle just costs you upfront.