How Many Solar Panels Do I Need?

Use this solar panel requirement calculator to work out how many solar panels your home needs, from your monthly electricity bill or a chosen system size, using today's 540W to 620W modules and your city's real sun hours.

Number of panels = system watts ÷ panel watts, rounded up. With today's 540 W to 620 W panels:

System	Panels needed	Roof area
1 kW	2	80 – 100 sq. ft.
2 kW	4	160 – 200 sq. ft.
3 kW	5 – 6	240 – 300 sq. ft.
5 kW	9 – 10	400 – 500 sq. ft.
10 kW	17 – 19	800 – 1,000 sq. ft.

A home using about 300 units a month needs roughly 3 kW, which is 5 to 6 panels.

Calculate Solar Panels Needed

Estimate by

State

City

Average monthly electricity bill

₹

Panel wattage Most 2026 residential installs use 540W to 620W mono modules.

Your Panel Count

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solar panels needed

System size–

Panel wattage used–

Roof area needed–

Estimated monthly generation–

Panel counts here are estimates. The final number depends on the exact module your installer stocks and on your roof layout, so ask a local solar contractor to confirm the system size and current price.

Built and maintained by Solar Calculators Pro · How we turn units into kW and panels

Number of Solar Panels by System Size (550W Modules)

System Size	Panels (550W)	Roof Area	Typical Monthly Output
1 kW	2	80 – 100 sq. ft.	110 – 130 units
2 kW	4	160 – 200 sq. ft.	220 – 260 units
3 kW	6	240 – 300 sq. ft.	330 – 390 units
5 kW	10	400 – 500 sq. ft.	550 – 650 units
10 kW	19	800 – 1,000 sq. ft.	1,100 – 1,300 units

Output ranges assume 4.5 to 5.2 peak sun hours, which covers most Indian cities. Check your city's exact figure with the solar generation calculator.

How to Calculate the Number of Solar Panels Required

Find your monthly units (kWh) on your electricity bill, or estimate them from your appliances with the solar load calculator.
Convert units to system size: kW = monthly units ÷ (peak sun hours × 30 × 0.8), rounded up to the next 0.5 kW.
Convert size to panels: panels = kW × 1,000 ÷ panel watts, rounded up.

Worked out for a typical city with 4.8 peak sun hours:

Monthly units	System size	Panels (540–620 W)
100	1 kW	2
200	2 kW	4
300	3 kW	5 – 6
400	3.5 kW	6 – 7
500	4.5 kW	8 – 9
1,000	9 kW	15 – 17

What Changes the Panel Count

Panel wattage: a 3 kW array needs 6 × 550W panels but only 5 × 620W panels. Higher-wattage modules save roof space at a small price premium.
Your consumption: the system is sized to your monthly units first; panels follow from the kW. A bigger AC load means more panels.
Sun hours: a home in Jodhpur (5.8 sun hours) needs fewer panels than the same home in Shillong (3.5) for identical consumption.
Roof space: if your roof is tight, verify fit with the solar roof area calculator before finalising the design.

Choosing Between Bill Mode and Size Mode

This calculator answers two different questions depending on the mode:

Bill mode answers "how many panels does my home need?" It converts your average bill into units, sizes the system, then counts panels. Use a 12-month average bill; a single winter bill will undercount panels for every AC-owning home in India.
Size mode answers "how many panels make up X kW?" Use it when an installer has already quoted a size and you want to verify the module count on the quote matches the wattage promised.
Panel wattage matters more than people expect. The same 3.3 kW array is 6 panels at 550W but 7 at 540W and only 5 at 620W, and each panel is roughly 21 sq. ft. of glass plus spacing on your roof.

Counting Panels for a Bhopal Home

A Bhopal household with a ₹2,500 monthly bill uses about 333 units at the city's ₹7.5 tariff. With 5.0 peak sun hours, the calculator sizes a 3 kW system: that is 6 panels of 550W, or just 5 panels if the installer supplies 620W modules. Either way the array needs 240 to 300 sq. ft. of shadow-free roof and will generate about 360 units a month, comfortably covering the family's usage with a small monsoon buffer.

What to Do With Your Panel Count

Check the quote line, not the headline. A "3 kW system" quote listing 6 × 500W panels is actually 3.0 kW only on paper from older stock; 6 × 550W is 3.3 kW. Multiply count × wattage yourself.
Verify the fit. Take your count to the solar roof area calculator and confirm your shadow-free area carries it with row spacing.
Ask for the layout drawing. Good installers provide a roof layout showing each panel position and orientation before installation day.
Match the inverter. The array's total wattage should sit at 1.0 to 1.2 times the inverter rating; the inverter size calculator checks this in seconds.

Where Panel Counts Go Wrong

Counting panels instead of watts. "10 panels" from 2019 (330W era) and "10 panels" today (550W era) differ by 2.2 kW. Watts are the currency; panels are just packaging.
Sizing for today only. An AC or EV planned within two years adds 2 to 4 panels; adding them later means structure and wiring rework.
Ignoring shading on one corner. Panels wired in a string sink to the shaded panel's output. Fewer, well-placed panels beat more panels with one shaded.
Forgetting the DISCOM sanction. Net-metering capacity is tied to your sanctioned load; confirm before buying a panel count the connection cannot legally host.

The Panel-Count Maths

System kW = Monthly units ÷ (Peak sun hours × 30 × 0.8)
Panels = ceil(System watts ÷ Panel wattage)

Module and sun-hour settings

Performance ratio: 0.8 for real-world losses (dust, heat, wiring, inverter)
Module range: 540W to 620W mono PERC / TOPCon panels, the 2026 residential standard
Sizing: rounded up to the nearest 0.5 kW so the system covers your full consumption

Panel Count Questions From Indian Homeowners

How many solar panels do I need for a 3 bedroom house in India?+

A typical 3BHK consuming 300 to 400 units a month needs a 3 to 3.5 kW system, which is 6 to 7 panels of 550W. Homes running two or more ACs through summer often step up to 5 kW, around 9 to 10 panels.

How many solar panels are needed for 1 kW?+

With modern 540W to 620W modules, a 1 kW array needs just 2 panels. Older 330W panels needed 3, which is why panel counts in old quotes look higher for the same capacity.

How many panels do I need to run a 1.5 ton AC?+

A 1.5 ton inverter AC draws about 1.2 kW while running. Accounting for real-world losses, dedicate roughly 1.5 kW of array, about 3 × 550W panels, for each AC that runs through the day, on top of your base load.

Is it better to use fewer high-wattage panels?+

Usually yes. Fewer 600W+ panels mean less mounting structure, less wiring and less roof area for the same kW. The per-watt price is slightly higher, but installation savings often cancel that out.

How much roof space do the panels need?+

Plan 80 to 100 sq. ft. of shadow-free roof per kW including maintenance walkways. Six panels of 550W (3.3 kW) need roughly 265 to 330 sq. ft. Run your exact case in the solar roof area calculator.

Can I add more panels later?+

Yes, if your inverter has headroom or you add a second inverter, and your net metering sanction allows the higher capacity. It is usually cheaper to size correctly once, so estimate honestly for the next 5 years of usage, including any planned AC or EV.

How many solar panels do I need for 500 units per month?+

About 8 to 9 panels of 550W. 500 units needs roughly a 4.5 kW system in a typical 4.8 sun-hour city, and 4,500 W ÷ 550 W rounds up to 9 panels, needing around 360 to 450 sq. ft. of roof.

Do more panels mean more savings?+

Only up to your consumption. Panels beyond what you use feed the grid at roughly ₹3 per unit, a third of what self-consumed units are worth. Size to your usage first, then add margin only for planned load growth.

How many solar panels do I need for 1,000 kWh a month?+

About a 9 kW system in a typical Indian city (4.8 sun hours), which is 15 to 17 panels of 540 to 620 W on roughly 720 to 900 sq. ft. of shadow-free roof.

How many solar panels do I need for a 2,000 sq ft house?+

Floor area does not decide it; your electricity use does. If your home uses 400 to 600 units a month, you need about 3.5 to 5.5 kW of solar, which is 6 to 11 panels depending on panel wattage.