Pergola Sizing: What Size Pergola for a 20 to 25 Square Metre Garden, or for Seating Eight?

For a garden of 20 to 25 square metres, a 3m x 3m pergola is the usual choice, covering 9m² and leaving the rest of the space open. To seat eight people under cover, you need at least 4m x 3m, and 6m x 3m is the comfortable answer if those eight are sitting around a dining table with chairs that pull out.

Pergola Sizes At A Glance

Size	Coverage	Seats comfortably	Suits
2.4m x 2.4m	5.8m²	2 to 4	Courtyards, balconies, bistro sets
3m x 3m	9m²	4 to 6	Small and medium gardens
3.6m x 3m	10.8m²	6	Medium gardens, 6 seat dining sets
4m x 3m	12m²	6 to 8	Family gardens, corner sofa sets
4m x 3.6m	14.4m²	8	Larger dining sets with clearance
6m x 3m	18m²	8 to 10	Long patios, dining plus lounging
6m x 3.6m	21.6m²	10 plus	Large gardens, two zones under cover

Sizing For A 20 To 25 Square Metre Garden

A garden of this size is typically around 5m x 4m or 5m x 5m. The guiding principle is to cover the seating area without swallowing the whole garden, because a pergola that fills the space makes the garden feel smaller.

• A 3m x 3m pergola uses roughly 36% to 45% of a garden this size. It covers a 4 to 6 seat dining set and leaves room for planting and a path around the edge.
• A 2.4m x 2.4m pergola suits the smaller end of this range, or gardens where you want a distinct sheltered corner with plenty of open lawn left over.
• A 3.6m x 3m pergola works if the garden runs to 25m² and the seating area is the main event.

As a rule of thumb, aim to keep the pergola under about half the total garden area, and leave at least 60cm of walking space along any edge people need to pass.

Sizing To Seat Eight People

Seating eight depends on what they're sitting on, so work backwards from the furniture.

• Eight at a dining table. An 8 seat round table is typically 1.8m across, and a rectangular one is around 1m x 2m. Add 70cm of chair clearance on every side and you need roughly 3.2m x 3.2m of clear floor for the round table, or 3.4m x 2.4m for the rectangular one. That rules out a 3m x 3m pergola for a round table, and points to 4m x 3m as the practical minimum. A 4m x 3.6m or 6m x 3m structure gives the chairs room to move without anyone catching a post.
• Eight on a corner sofa. Corner seating is more compact, since nothing needs pulling out. A 4m x 3m pergola covers most 8 seat corner sets comfortably.
• Eight across two zones. If you want a dining table and separate lounge seating under one structure, 6m x 3m or 6m x 3.6m is the size to look at.

The Measurements That Actually Decide It

Three numbers do most of the work.

1. Your furniture footprint, taken from the product page, including the table and the chairs at rest.
2. Chair clearance, at roughly 70cm behind each seat so chairs can be pulled out.
3. Circulation space, at 60cm or more on any side used as a route.

Add those together and you have the minimum covered area. Then check the figure against your patio, because a pergola needs a firm, level base such as concrete paving, with each corner leg bolted down through its base plate.

Height And Position

Height matters as much as footprint. Check the overall height on the product page against where the structure will sit, particularly if it's going close to a boundary, since planning rules are tighter within 2m of one.

Position affects the usable area too. A structure placed hard against a fence loses the walking space on that side, which effectively makes it smaller in practice.

Don't Forget The Accessories

Side panels, pull down screens and sliding doors all mount to the frame, so they don't reduce the covered area. Heaters and lighting mount overhead for the same reason.

What does affect usable space is furniture placed against a post. Leave a clear run between the legs on any side you'll walk through, and plan where the dining table goes before you choose the size.

Finding The Right Size For Your Garden

Our pergola collection covers every size from 3m x 1.5m through to 6m x 3.6m, across the Torino and Rivaro ranges, with full dimensions listed on each product page.

Send us your garden measurements and a note of the furniture going underneath, and our team will recommend a size. We can quote for nationwide installation at the same time if you'd like the structure fitted for you.

FAQs

What size pergola do I need for a 20m² garden?

A 3m x 3m pergola is the usual answer, covering 9m² and leaving the rest of the garden open. A 2.4m x 2.4m model suits gardens where you want more open space.

What size pergola seats 8 people?

4m x 3m is the practical minimum for eight around a dining table, and 6m x 3m is more comfortable once chairs are pulled out. An 8 seat corner sofa fits within 4m x 3m.

How much clearance do you need around furniture under a pergola?

Around 70cm behind each dining chair, plus 60cm on any side used as a walkway.

Is a 3m x 3m pergola big enough for a 6 seat dining set?

It covers a 6 seat set, though clearance is tight on a round table. If you have the space, 3.6m x 3m gives the chairs more room.

Can a pergola be too big for a garden?

It can. Keeping the structure under about half the total garden area stops the space feeling enclosed and keeps the lawn and planting in proportion.

What base does a pergola need?

A firm, level surface such as concrete paving or a patio, with each corner leg bolted down. A slight gradient helps rainwater run away from the drainage outlets.