Solar Panel Sizes and Dimensions in the UK: mm, Weight and Roof Fit

Most solar panels fitted to UK homes in 2026 measure about 1,722 to 1,762 mm long by 1,134 mm wide and 30 mm deep, weigh around 21 kg and are rated at roughly 415 to 460 W. These are 54-cell panels made of 108 half-cells. Larger 72-cell panels of about 2,278 by 1,134 mm reach 555 to 575 W but weigh about 28 kg.

Panel size decides how many fit on your roof, how much the array weighs, whether a plug-in kit fits your balcony and whether a replacement will match an old panel. This guide gives the dimensions from manufacturers’ data sheets, the arithmetic for typical British roofs and the planning limits that depend on size. For choosing between one and two panels on a plug-in kit, see our separate guide to 400 W versus 800 W plug-in solar.

Why panels come in a few standard sizes

A solar panel is a grid of silicon cells laminated between glass and a back sheet, framed in aluminium. Its size follows from three things: the size of each cell, how many cells there are, and how they are arranged.

Cells and half-cells. Almost every panel sold today uses half-cut cells: each square cell is cut in two, which lowers the current in each half and reduces resistive losses. A “54-cell” panel therefore shows 108 half-cells on its data sheet, a “60-cell” panel 120, a “66-cell” panel 132 and a “72-cell” panel 144. Jinko’s data sheet for its Tiger Neo 54HL4R, for example, gives the cell count as 108 (54 × 2).

Width settled at 1,134 mm. Every current panel in our table below shares a width of 1,134 mm. The length varies with the number of cells and their exact dimensions. Jinko’s latest 54-cell panel is 1,762 mm long, 40 mm longer than LONGi’s 1,722 mm panel with the same cell count, which appears to reflect slightly larger, rectangular cells in the newer design.

Cell count alone is not enough. Trina’s Vertex S+ NEG9R.28 lists 144 cells yet measures the same 1,762 by 1,134 mm as Jinko’s 108-cell panel, because it cuts its cells differently. Two panels described as “144 cells” can therefore be 1.76 or 2.28 metres long. Always read the dimensions line on the data sheet, not the cell count in the product name.

Dimensions and weights from data sheets

The table lists panels from three of the largest manufacturers, taken from their published data sheets. It is a cross-section of what UK installers fit, not a recommendation.

Table scrolls sideways

Retailer listings for JA Solar’s 132 half-cell JAM66D45 panel give about 2,382 by 1,134 mm, roughly 32 to 33 kg and 595 to 630 W; we could not open JA Solar’s own data sheet to confirm the figures, so they stay out of the table. Panels of 600 W and more are mostly made for solar farms and commercial roofs.

Two patterns stand out. Efficiency is now so similar across formats that a bigger panel simply means more watts in proportion to its area: every panel in the table delivers between about 210 and 230 W per square metre of its own surface. And weight per square metre is almost constant too, at about 10.5 to 11 kg. Choosing a bigger panel does not save roof space; it only changes how the space is divided.

Older panels are a different story. Panels installed a decade or more ago were generally smaller in both directions and much lower in power, which matters when one fails: a modern replacement will rarely match the old frame size, rail spacing or electrical values. An installer may need to re-space the rails or replace a whole string rather than a single panel.

Power per square metre and kWp per roof area

Because current panels deliver 210 to 230 W per square metre, the rule of thumb is simple: 1 kWp of panels needs about 4.5 square metres of panel area. On a roof you also lose space to gaps between panels, usually around 20 mm for the clamps, and to margins at the edges, so plan on roughly 5 to 6 square metres of usable roof per kWp.

The Energy Saving Trust’s figure for an average home system fits this: a 4.5 kWp system typically covers 20 to 30 square metres of roof and uses around 12 panels. Twelve 440 W panels make 5.28 kWp and cover about 23.4 square metres of panel area; ten of them make 4.4 kWp on about 19.5 square metres.

What that roof area produces depends on where you live. PVGIS, the European Commission’s solar database, estimates about 1,019 kWh a year per kWp in London, 886 kWh in Manchester and 903 kWh in Edinburgh for panels facing south at 35 degrees with standard system losses. A 5.28 kWp array would therefore produce roughly 4,700 to 5,400 kWh a year on a south-facing roof, less facing east or west; the Energy Saving Trust says east or west-facing systems tend to get 15 to 20 percent less than south-facing ones.

How many panels fit on a typical UK roof

The only reliable answer comes from measuring your roof, but the arithmetic is easy to follow. In the examples below, the margins are our illustrative assumption: 300 mm at each verge (the sloping side edges) and 400 mm at the eaves and ridge, with 20 mm gaps between panels. Installers set the real margins from the mounting system’s wind-load design and the roof’s layout, and they may be larger.

Example 1: a semi-detached house, rear roof slope

Roof slope 8.0 m wide along the eaves and 4.6 m from eaves to ridge measured along the slope. After margins, the usable area is 7.4 by 3.8 metres.

Table scrolls sideways

Each division adds one gap to the usable dimension and rounds down to whole panels. The standard 54-cell panel fills this roof neatly in either orientation. The large panel either wastes a strip of roof or forces a landscape layout, ending up with less power and panels that weigh 28 kg each to lift up a scaffold.

Example 2: a terraced house, small rear slope

Roof slope 4.5 m wide and 3.6 m deep along the slope; usable area 3.9 by 2.8 metres after margins.

Table scrolls sideways

On shallow slopes landscape often wins, because two rows of 1,134 mm fit where one row of 1,722 mm does. Many terraced houses also have a front slope or an outrigger roof that adds capacity, but a front elevation in a conservation area is restricted, as the planning section below explains.

Measuring your own roof

What reduces the count

Chimneys, soil vent pipes, roof windows and dormers each take out one or more panel positions. Hipped roofs have triangular slopes that fit fewer rectangular panels than their area suggests. Shading from neighbouring buildings or trees can make some positions not worth filling. And valleys, ridges and verges with weak or awkward fixings may need larger margins.

Weight and the roof structure

At 20.8 to 24.2 kg for the panels most homes use, the array weighs about 10.5 to 11 kg per square metre before rails, clamps and roof hooks. Twelve 21 kg panels add about 250 kg to a roof slope, spread over more than 20 square metres. Most sound pitched roofs carry that comfortably, but installers should check the rafters and battens, especially on older roofs, roofs with heavy concrete tiles already near their limit, or roofs altered for loft conversions.

Manufacturers rate panels for static loads from wind and snow. LONGi’s installation manual gives 5,400 Pa on the front (wind and snow pressure) and 2,400 Pa on the back (wind suction) for its standard mounting methods, and Jinko’s 54HL4R data sheet cites test loads of 6,000 Pa front and 4,000 Pa rear. Those figures only hold when the panel is clamped in the zones the manual specifies, which is one reason rail spacing depends on the exact panel model. MCS publishes product standards for roof mounting kits, and an MCS installer designs the fixings for your roof’s wind exposure.

Frames, glass and thickness

Most roof panels are 30 mm deep; some, such as Jinko’s 72-cell Tiger Neo in our table, use a 35 mm frame. The depth matters to the installer because the clamps that hold panels to the rails come in heights matched to the frame, and mixing frame depths on one array means mixing clamps.

Glass is the other difference. A conventional panel pairs a single sheet of front glass with a polymer back sheet; Jinko’s 54-cell data sheet, for example, specifies 3.2 mm of tempered front glass. Glass-glass panels, such as Trina’s Vertex S+ NEG9R.28, sandwich the cells between two thinner sheets, 1.6 mm of heat-strengthened glass on each side in Trina’s case. The two types end up within about a kilogram of each other in our table, so the choice rests on warranty terms, appearance and price rather than weight or size. Bifacial glass-glass panels can also collect light reflected onto their rear face, which helps on raised frames over pale surfaces but adds little flush on a tiled roof.

Flat roofs: tilt, height and row spacing

On a flat roof, panels sit on tilted frames, and their size sets two limits: the height allowed under permitted development and the gap needed between rows so one row does not shade the next.

Height. In England the highest part of the equipment may be no more than 0.6 metres above the highest part of a house’s flat roof. The rise of a tilted panel is its length times the sine of the tilt angle. A 1,722 mm panel in portrait at 30 degrees rises 1.722 × 0.5 = 0.86 m, well over the limit. The same panel at 20 degrees rises about 0.59 m, and in landscape at 30 degrees, using its 1,134 mm side, about 0.57 m. Add the frame’s own clearance above the roof surface before deciding: low-tilt or landscape layouts are usually the ones that stay within 0.6 metres.

Row spacing. Rows need space so that the low winter sun clears the row in front. At noon on the shortest day, the sun in London stands only about 15 degrees above the horizon. A 1,722 mm panel tilted at 15 degrees rises about 0.45 m, which casts a shadow about 1.66 m long at that sun angle; with the panel’s own horizontal depth of about 1.66 m, rows would need to start about 3.3 m apart to avoid any shading at midwinter noon. Designers usually accept some shading in December and January, when output is small anyway, and use a closer spacing based on the sun in February or March. Low tilts and east-west layouts, with pairs of panels leaning against each other, fit more panels on the same roof for exactly this reason.

Planning limits that depend on size

England

The General Permitted Development Order 2015, Part 14, sets the limits for solar equipment at houses. On a pitched roof, panels must not project more than 0.2 metres beyond the roof slope or rise above the highest part of the roof, chimneys excluded. On a flat roof, the highest part must not be more than 0.6 metres above the highest part of the roof, which limits how steeply large panels can be tilted on frames. A standard on-roof mounting with a 30 mm panel usually stays well inside the 0.2 metre limit.

There is no edge distance for houses in the order. Non-domestic buildings are different: under Class J, roof-mounted PV may not be installed within 1 metre of the external edge of the roof. If you are planning panels on a workshop, farm building or commercial unit, that metre comes off every side of the usable area.

Stand-alone panels in a garden face the strictest size limit: the panel surface may not exceed 9 square metres. That is four panels of 1,722 by 1,134 mm (7.8 square metres) or four of 1,762 mm (8.0 square metres), but not five, which would be 9.8 to 10 square metres. With 440 to 460 W panels, a garden array without a planning application tops out at about 1.8 kWp. Height limits also apply: 4 metres in general, 2 metres within 5 metres of the boundary, and 1 metre within 5 metres of the boundary in front of the house.

Scotland, Wales and Northern Ireland

Planning is devolved. Scotland’s Class 6HA, in force since May 2024, allows building-mounted solar PV on a dwelling to protrude up to 1 metre from a wall, roof plane, ridge or chimney. Wales allows panels on a dwelling to protrude no more than 20 centimetres beyond a wall or pitched roof. Northern Ireland has its own order, which we have not reviewed for this guide. Listed buildings and conservation areas carry extra restrictions in every nation; our plug-in solar planning guide lays out the nation-by-nation rules in more detail.

Plug-in solar sizes and the 2,000 W panel limit

Plug-in solar became legal in England, Scotland and Wales on 27 August 2026. SI 2026/848 caps the output at 800 W and requires compliance with the government’s Plug-in Solar Device Interim Product Specification (version 2.0, July 2026), which sets the size limits. A kit may have up to four panels, no more than two of them in series, with no more than 2,000 W of panel capacity in total. The open-circuit voltage at the inverter may not exceed 120 V DC, and above 960 W of panels the manufacturer must advise you to consider a professional assessment of your electrical installation. Northern Ireland is not covered.

Table scrolls sideways

The voltage limit matters for how panels are wired. A 54-cell panel such as Jinko’s 54HL4R has an open-circuit voltage of about 39 to 40 V at standard test conditions, rising by about 0.25 percent for every degree colder than 25 °C. Two in series stay near 80 V; three in series would already reach about 120 V on a mild day and exceed it on a frosty morning, which is why the specification allows no more than two panels in any series string. In practice, approved kits come with the panels and wiring specified, and the ENA Type Test Register listing covers the kit as sold, so stick to the configuration in the instructions.

Physical size is the other constraint. A 1.72-metre panel on a balcony railing is heavy and catches the wind, and the specification requires a supplied mounting system with a structural analysis for UK wind and snow loads. For which kit size suits your balcony, see 400 W versus 800 W plug-in solar; for mounting options, our guide to mounting a panel on a balcony railing; and for the legal conditions in full, is plug-in solar legal in the UK.

Handling and transporting panels

A standard panel is light enough for one person to carry, but at nearly 2 square metres it behaves like a sail in a breeze and its glass and frame corners are easily damaged. LONGi’s installation manual sets the basic rules:

• keep panels in their packaging until they reach the installation site, stored somewhere ventilated, dry and out of the rain;
• do not stack cartons higher than the limit printed on the packaging, and do not drop a module onto another;
• never lift a panel by its junction box or cables;
• never stand or walk on panels, or put heavy objects on the glass;
• take particular care setting panels down on their corners.

If you collect panels yourself, measure the vehicle first: a panel needs a flat load space of at least 1.8 by 1.15 metres to lie without flexing, and should travel flat or on its long edge, well padded, never with other loads on top. Jinko ships its 54-cell panels 37 to a pallet measuring 1,792 by 1,140 by 1,249 mm, which gives a sense of the boxed size. Carrying panels up a ladder is a job for two people at least, and on most roofs it is a job for scaffolding and an installer.

Choosing panel size: a checklist

• Measure the roof slopes you want to use: width at the eaves and depth along the slope, with chimneys and windows marked.
• Ask which exact panel model is quoted, and check its data sheet for length, width, depth, weight and power class.
• Compare quotes in kWp and in panel count, not panel count alone; twelve 440 W panels and ten 520 W panels differ in both.
• Ask how the installer sets edge margins and how the layout handles wind zones near the verges and ridge.
• Check the weight if the roof is old or altered, and ask whether a structural check is included.
• Think about replacements. A widely used format such as the 54-cell panel will be easier to match in ten years than an unusual size.
• Check planning for flat roofs, garden arrays over 9 square metres, conservation areas and listed buildings.

Common mistakes and edge cases

• Buying by wattage alone. Consequence: a high-wattage panel that does not fit the roof in two rows. Fix: lay out the roof with the panel’s real dimensions first.
• Assuming “144 cells” means a large panel. Consequence: confusion when comparing quotes. Fix: compare dimensions, not cell counts.
• Ignoring margins. Consequence: a layout that looks fine on a sketch but cannot be fixed safely near the verge. Fix: let the installer’s mounting design decide.
• Five panels on a garden frame. Consequence: over the 9 square metre limit for stand-alone solar in England. Fix: four panels, a roof, or a planning application.
• Mixing old and new panels in one string. Consequence: the string runs at the weakest panel’s current. Fix: ask the installer whether a separate string, an optimiser or a microinverter is needed.
• Plug-in kits wired beyond the limits. Consequence: a kit that is no longer compliant. Fix: keep to the approved configuration and the four-panel, 2,000 W limits.

Costs, VAT and export payments

The Energy Saving Trust puts the typical cost of a 4.5 kWp home system at about £7,600 as of October 2026. Panel size has little direct effect on that price: what you pay for is kWp, mounting, scaffolding and labour. Installation of solar panels in residential accommodation is zero-rated for VAT until 31 March 2027 under HMRC’s Notice 708/6, with the rate due to revert to 5 percent from 1 April 2027, while panels bought from a retailer without installation are standard-rated at 20 percent.

To receive Smart Export Guarantee payments for electricity you export, Ofgem’s rules require an installation certified under MCS or an equivalent scheme. That is a reason to let an MCS installer choose and fit roof panels, whatever their size. Panels on a roof also need occasional checks; our guide to solar panel cleaning and servicing covers what that involves and costs.

Next steps

• 800 W versus 400 W plug-in solar: which size is right
• Solar panel cleaning and servicing in the UK
• Solar pool heating in the UK