Gridly
Solar Panel Roof Estimator
How many solar panels can fit on your roof? Enter your available roof area and panel wattage to see what system you could install.
Typical north-facing section: 20–60 m²
A good unobstructed roof: 75–85%. Lots of vents/chimneys/shading: 50–65%.
Panels that fit
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System size
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kW
Annual output
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kWh/yr
Est. system cost
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What that system could power
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average household days/yr
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free EV km/year
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est. bill saving/yr
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est. payback
Estimates only
Panel dimensions vary by manufacturer (typically 1.7–2.1m × 1.0–1.1m). A 20% spacing allowance is included in the area calculation. Annual output assumes a north-facing, unshaded roof at optimal tilt. Actual output depends on orientation, shading, temperature, and system losses. System cost is based on approximate installed price of $900–1,100/kW for a quality system in Australia (2026).