UK Home Battery Storage
Battery Sizing
Calculator
Find the right battery capacity for your UK home. Based on your energy usage, solar setup, and goals — recommendations are rounded to real-world product sizes.
Energy & Solar
Your annual electricity consumption and solar system size (if any).
Annual electricity usage
?
Check your energy bills or smart meter. UK average: ~3,500 kWh/yr
kWh
Solar system size
?
Optional — needed for self-consumption mode. Leave at 0 if no solar.
kWp
Usage Pattern & Goals
When you use electricity and what you want your battery to achieve.
Daytime electricity usage
?
Share of usage during daylight hours (roughly 8am–6pm)
Electricity tariff
?
Battery goal
?
Your Results
Recommended size
—
nearest standard size
Usable capacity
—
at 90% depth of discharge
Night demand covered
—
Estimated daily energy flow
Solar —
→ Day use —
↳
Battery —
→ Night use —
Recommendations are rounded to standard battery product sizes (5, 10, 13.5, 20 kWh) and assume a performance ratio of 0.85, round-trip efficiency of 90%, and 90% depth of discharge. Actual performance varies by product, usage pattern, and temperature. Consult a qualified MCS-accredited installer for a site-specific assessment.