How Many Solar Panels for 3kW, 2kW and 5kW Systems

How many solar panels for 3kW? Six panels if your installer uses 540W or 550W modules, five if they use 600W modules, and eight if they still use 400W modules. A 2kW system takes four modern panels and a 5kW system takes nine or ten. That is the whole answer for most quotes, but the count is the easy part. Three things decide whether that count is right for your roof: the wattage printed on each panel, whether the panel string sits inside your inverter's voltage window, and the fact that the PM Surya Ghar subsidy is paid on the DC capacity of the panels, not on the inverter rating. This page gives you the lookup tables first and the checks second.

At a glance: panel count by system size

Based on 540W to 550W modules, the most common rooftop size in India in 2026.

Units per month use 4 to 4.5 units per kWp per day, the planning figure used across our solar sizing guide. Roof figures use 80 to 100 sq ft per kWp, which allows for walkways, parapet shadow and row spacing.

How many solar panels for 3kW: the full count by panel wattage

The rule installers use is simple: take the smallest whole number of panels whose combined wattage reaches the target. The table applies that rule to every common wattage.

Two rows deserve a second look. With 590W modules, five panels give 2.95 kWp, which is just under 3kW, so a "3kW" quote built on five 590W panels is really a 2.95 kWp plant. With 400W modules, a 3kW plant needs eight panels and roughly 30% more roof than six 540W panels. If your roof is tight, panel wattage matters more than panel brand.

How many solar panels for 2kW

Four panels of 540W to 600W, or five panels of 400W to 450W. A 2kW plant is the size where the central subsidy is still paid at the full ₹30,000 per kW rate, so many households in the 200 to 300 units a month band stop here. Our 2BHK solar guide shows which homes this size suits.

One honest note: four 540W panels make 2.16 kWp, not 2.00. That extra 0.16 kWp is useful generation, about 20 units a month, but it also means your application, your sanction and the panel labels all have to say the same number. Tell your vendor the exact kWp you want on the application before they order panels.

How many solar panels for 5kW

Ten panels of 540W or 550W, or nine panels of 590W to 600W. At this size the count is no longer the hard part. The string voltage is. Ten 540W panels in one series string reach about 523V on a cold winter morning, which is above the 450V maximum input of some 3kW to 5kW inverters sold in India. The fix is either an inverter rated for 600V input or two strings of five panels on a dual-MPPT inverter. The voltage table below shows the numbers.

Before you buy 5kW, check that your consumption supports it. The subsidy stops growing at 3kW, so kilowatts four and five are bought at full price, a point our 5kW solar price guide covers in detail.

How many solar panels for 1kW

Two 540W to 600W panels, or three 400W to 450W panels. The trap here is the inverter, not the panel count. Two 540W panels in series give about 83.5V at their maximum power point under test conditions, and that falls further on a hot afternoon. Some 3kW string inverters, including both models in the table below, do not track below 80V to 100V. If you buy a larger inverter "for later expansion" and connect only two panels to it, it may sit idle for part of the day. A 1kW system needs a 1kW-class inverter with a low start voltage, or three smaller panels.

Solar panel wattage: why the same 3kW can be five, six or eight panels

Panel wattage today runs from about 400W (older 108-cell modules) to 590W and above (large-format TOPCon and bifacial modules). Higher wattage per panel means fewer panels, fewer clamps and less wiring, but each panel is bigger and heavier. A 540W dual-glass bifacial module measures 2272 x 1133 mm and weighs 32.5 kg (Waaree Bi-55-540 datasheet). Six of them put about 195 kg of glass on your roof before the structure.

Wattage is not efficiency. A 600W panel is not better per square foot than a 540W panel of the same cell technology; it is just larger. For the efficiency comparison, read our guide to monocrystalline vs polycrystalline panels.

The inverter check: string voltage and current

Panels on Indian rooftops are usually wired in series, one panel's positive to the next panel's negative, so their voltages add. That is the same rule as battery series vs parallel connection, applied to panels. The string voltage has to sit inside the inverter's MPPT window, and on a cold morning it must stay below the inverter's maximum DC input.

String voltage using a 540W module (Vmp 41.75V, Voc 49.61V, Voc temperature coefficient -0.27% per °C):

Now compare that with two real 3kW inverters:

The current point is new. Large 540W to 600W modules run at 13A or more, and some older single-MPPT inverters accept 12.5A. That is safe if the inverter's short-circuit current rating covers the panel's Isc (13.83A here), but you lose a few percent at noon peaks. Ask your installer to show the panel Imp and Isc against the inverter's input current ratings on one sheet.

Mild oversizing is normal. A 3kW inverter with 3.24 kWp of panels runs at a DC to AC ratio of 1.08, and residential designs commonly use 1.10 to 1.30 with clipping losses of about 0.3% to 1.2% a year at the lower end of that band. Our on-grid solar inverter guide explains how the inverter handles the extra.

The subsidy counts panels, not the inverter

This is the fact most panel-count pages leave out. MNRE's PM Surya Ghar operational guidelines (June 2024, Section 5(k)) say the central financial assistance is paid on "the rated DC capacity of the module system" and "not as per the inverter capacity". Section 5(m) adds that the modules must meet the Domestic Content Requirement, meaning Indian-made modules with Indian-made cells.

What that means for your count:

So the inverter rating does not raise or lower your subsidy, and non-DCR panels remove it entirely. Our PM Surya Ghar eligibility guide covers the rest of the conditions.

Roof space for solar panels: glass area vs planning area

A 540W panel covers 2.57 square metres, about 27.7 sq ft. Six panels are 166 sq ft of glass, but you cannot plan on 166 sq ft of roof for a 3kW system. You need clearance from the parapet, a walkway for cleaning, space for the inverter and earthing runs, and row spacing so one row does not shade the next in winter. That is why the planning figure is 80 to 100 sq ft per kWp, or roughly 260 to 330 sq ft for 3kW.

3kW solar system panel size, in feet: each 540W to 550W module is about 7.5 ft long and 3.7 ft wide. Six of them in two rows of three, long side horizontal on an elevated structure, need a clear rectangle of roughly 23 ft by 15 ft once you add spacing. Water tanks and stair rooms are what usually break this layout.

Honest pros and cons: fewer big panels vs more small panels

Decision framework

Strong fit for six 540W to 550W panels (3kW): a flat, mostly unshaded roof of 300 sq ft or more, consumption of 300 to 450 units a month, and a single-phase 3kW inverter with a 450V to 600V input rating.

Marginal fit: a cramped roof with a water tank in the middle, where seven or eight smaller panels arranged around obstacles may outperform six large ones that cannot all face south.

Not a fit: two large panels on a 3kW inverter "for future expansion", ten panels in one string on a 450V inverter, or non-DCR panels on a system you expect to claim subsidy on.

If you plan to add batteries for power cuts, the panel count stays the same, but the inverter changes. Our guide to hybrid inverter vs normal inverter explains which one your panels will connect to.

FAQs

How many solar panels for 3kW do I need?

Six panels if you use 540W or 550W modules, five if you use 600W modules, and eight if you use 400W modules. Six 540W panels give 3.24 kWp, which qualifies for the full ₹78,000 central subsidy if the panels meet the domestic content rule.

How many solar panels for 2kW are needed?

Four panels of 540W to 600W, or five panels of 400W to 450W. Four 540W panels make 2.16 kWp and generate roughly 260 to 290 units a month.

How many solar panels for 5kW are needed?

Ten panels of 540W or 550W, or nine panels of 590W to 600W. Check the inverter's maximum DC input before putting all ten in one string, because ten 540W panels reach about 523V on a cold morning.

How many solar panels for 1kW are needed?

Two panels of 540W to 600W, or three of 400W to 450W. Pair them with a 1kW-class inverter that starts at a low voltage, because two large panels produce only about 83V at their maximum power point.

What solar panel wattage is best for a home in India?

For most rooftops, 540W to 590W modules give the fewest panels and the lowest cost per watt. On small or obstructed roofs, 400W to 450W modules can fit around obstacles better even though you need more of them.

How much roof space for solar panels does a 3kW system need?

Plan for 260 to 330 sq ft of shadow-free roof. The six panels themselves cover about 166 sq ft, but spacing, walkways and parapet shadow take the rest.

What is the 3kW solar system panel size?

Each 540W to 550W panel is about 2272 x 1133 mm, or roughly 7.5 ft by 3.7 ft, and weighs about 32 kg for a dual-glass bifacial model. A 3kW system has six of them.

Does a bigger inverter increase the solar subsidy?

No. MNRE's guidelines pay the subsidy on the DC capacity of the panels, not on the inverter rating. The central subsidy rises to ₹78,000 at 3 kWp of panels and does not increase beyond that.

Do I need batteries with a 3kW solar system?

Not with an on-grid system, which uses the grid as storage through net metering. You need batteries only if you want power during cuts, and then the battery bank has to be sized for your backup hours. The discharge-rate correction in our VRLA battery backup time guide applies to any lead-acid bank.

Conclusion

How many solar panels for 3kW comes down to panel wattage: six 540W to 550W panels for most quotes, five 600W panels or eight 400W panels at the edges. For 2kW it is four modern panels, and for 5kW it is nine or ten. Before you sign, check three things on paper: the DC kWp printed on the panel labels matches your application, the string voltage stays inside your inverter's input limits on a cold morning, and the panels are DCR-certified if you are claiming subsidy. For prices at each size, see our 3kW solar panel price guide.