Why Solar
See my rebate

How Many Solar Panels Do I Need?

Enter your electricity bill and location to find out how many panels your home needs and what it will cost.

Share with a mate

Your details

4.8 peak sun hours a day

$100$2,000
How much do you want to offset?

Your electricity usage

Daily
17.4 kWh
Annual
6,337 kWh

You need, estimated

12panels

5kW system (estimated)

Roof space
24m²
Est. cost*
$4,500
Est. savings a year
$1,076

How we calculated this

Your daily usage
17.4 kWh
Target offset
100%
Peak sun hours (NSW)
4.8h a day
Estimated system size needed
4.3kW
Panel wattage
440W
Recommended system
5kW (12 panels)

*Cost estimate after federal STC rebate. Based on 440W panels and 4.8 peak sun hours a day, the New South Wales average, with a 15% allowance for inverter, heat, dust and wiring losses. Savings assume 35% of the solar is used at home at the state tariff and the rest exported at 5c/kWh. Actual costs vary by installer and equipment.

Get an exact quote for your roof

A site assessment will confirm the right panel count for your roof angle, shading, and usage. One Why Solar Approved installer sends one free written quote, and a solar expert goes through it with you before you sign.

See my rebate

Frequently asked questions

How many solar panels does a typical Australian home need?
Most Australian homes need between 15 and 20 solar panels (a 6.6kW system) to cover their electricity usage. Larger homes with pools, air conditioning, or electric vehicles may need 22 to 30 panels (10 to 13kW).
How much roof space do I need for solar panels?
Each standard 440W solar panel takes up about 2m² of roof space. A typical 6.6kW system (15 panels) needs roughly 30m² of unshaded, north-facing roof. East and west-facing panels produce about 10 to 15% less.
Does my location affect how many panels I need?
Yes. Homes in sunnier states like Queensland and Western Australia (5+ peak sun hours) need fewer panels than homes in Tasmania or Victoria (3.5 to 4 hours). A Melbourne home may need 18 panels where a Brisbane home needs 14 for the same output.
Should I get more panels than I need?
Slightly oversizing your system (by 10 to 20%) is common practice. It accounts for panel degradation over time, cloudy days, and allows headroom if you add a battery or EV charger later. The cost per extra panel is relatively small.

How this panel calculator works

Enter your daily electricity usage (from your bill) or quarterly bill amount, select your state, and choose what percentage of your usage you want to offset. The calculator uses state-specific peak sun hours and standard 440W panel specs to recommend a system size and panel count.

The number of panels you need depends primarily on your electricity consumption and your location. Queensland and WA homes need fewer panels than Victorian or Tasmanian homes to produce the same energy, because they receive more peak sun hours per day.

Installer in hi-vis and a safety harness fitting solar panels on a tin roof

Common questions

How many solar panels does a typical Australian home need?
Most Australian homes need 15 to 20 panels (a 6.6kW system) to cover their electricity usage. This suits a household of 3 or 4 people using 15 to 25kWh per day. Larger homes with pools, ducted AC, or an EV may need 22 to 30 panels (10 to 13kW).
How much roof space do I need for solar panels?
Each standard 440W panel takes about 2m² of roof space. A 6.6kW system (15 panels) needs roughly 30m² of unshaded roof. North-facing is ideal, though east and west-facing panels produce about 10 to 15% less. Your installer will assess usable roof area during the quoting process.
Can I add more panels later?
Yes, but it depends on your inverter capacity. If you installed a 5kW inverter, you can connect up to 6.6kW of panels under the CEC 133% oversizing rule. To go beyond that, you would need a larger inverter or a second inverter. Planning for future expansion at install time is more cost-effective than retrofitting.
Up to $8,000+ in solar and battery rebates · Federal rebates step down in 80 daysSee how we calculate this