Free tool · 60+ countries
Home battery calculator
See in about a minute what a home battery saves you per year, which capacity fits and how long the payback takes — based on the prices, feed-in rules and taxes in your country.
How the calculator works
- Choose your country — and your state or province for the US and Canada.
- Enter your yearly grid consumption and, if you have solar, your export.
- We simulate all 8,760 hours of the year and recommend a capacity.
- Open advanced settings to adjust prices, battery cost, efficiency and cycles.
Why savings depend on where you live
The same battery pays back in five years in one country and fifteen in another. Four things decide it.
Electricity price
The more you pay per kWh, the more each stored kWh is worth. We pre-fill your local average; change it to your own supplier’s rate.
Feed-in rules
With full net metering the grid is already a free battery. With low or no export payment, storage captures value that would otherwise be lost.
Dynamic tariffs
Where hourly pricing exists, a smart battery charges cheap and discharges expensive. We only show this scenario where such contracts are available.
Tax and incentives
VAT treatment, rebates and deductions differ per country and change often. The model uses the rules that apply on the date you run it.
What we assume, and why
- Savings can never exceed what you actually consume at night. Most calculators skip this; ours enforces it.
- Cloud variability is modelled instead of using smooth averages, which would overstate the result.
- Inverter power limits are applied per hour, so a small unit cannot cover a large evening peak.
- Battery degradation and round-trip losses are included in the payback figure.
Our numbers are usually lower than those of sellers. That is deliberate.
Keep me up to date
Tariff changes, incentive deadlines and payback updates — once a month.