Free tool
Solar calculator
A rough estimate of what you need: system size in kWp, the space it takes and the expected annual production. The figures are for planning only; the real size is set by a site survey.
Solar calculator
Rough estimate
Enter your bill or consumption to see the result.
- System size
- kWp
- Approximate area
- m²
- Approximate annual production
- kWh per year
- Monthly consumption used:
- kWh per month
Actual size and savings depend on a site survey — compare offers from qualified installers.
Request offers for this sizeHow we calculate
- Monthly consumption = bill ÷ price per kWh (or the figure you enter directly).
- Target consumption = annual consumption × the share you choose.
- System size (kWp) = target consumption ÷ (peak sun hours × 365 × 0.75). The 0.75 is an approximate performance ratio covering heat, dust, inverter and cable losses.
- Area ≈ 5.5 to 7 m² per kWp, depending on the panels and the spacing between rows.
- For farms: one litre of diesel ≈ 3 kWh from a generator, which varies with the generator and its load.
- We don’t calculate a price or a payback period — they depend on the equipment, installation and your actual tariff.
How to use the result
The figure gives you a sense of scale before you speak to installers: a small system for a villa, tens of kWp for a warehouse, or hundreds for a factory. That lets you compare offers knowingly and notice when one is much smaller or larger than you need.
For a better figure, use the average of a full year of bills instead of one month, because summer consumption differs a lot from winter because of air conditioning. Read how to size a system from your bill.
What the calculator doesn’t tell you
The calculator doesn’t know your roof or the shade on it, your connection capacity, the grid-connection limits or when in the day you use power. A site survey settles those, and they can change the right size. That is why we show no price and no payback period: without a survey any such number is a guess. See what drives the price in the cost guide.
Calculator questions
Where do I find my price per kWh?
On your bill: divide the consumption charge by the number of kWh. Tariffs differ by account type (residential, commercial, industrial, agricultural) and consumption tier.
Why don’t you show a price?
Because the price depends on the equipment, mounting, site condition and warranties, and any number without a survey would be misleading. Real offers come from installers after the survey.
Should I cover all of my consumption with solar?
Not always. Space, connection limits and when you use power can make covering part of your consumption the better choice. A qualified installer will suggest the right share.
Do you store the figures I enter?
No — the calculation runs in your browser. If you tap “Request offers” we carry the estimate into the form only, and nothing is sent until you submit the request with your consent.
Still have a question?
Send your request and the qualified solar installers will answer your questions directly with their offers.