Choosing the right pergola size isn't simply a case of measuring the space you have available.

The pergola needs to work with the proportions of your garden, accommodate the furniture you want to use and leave enough room to move comfortably around it. A structure that looks generous on paper can feel surprisingly compact once you've added a dining table, chairs and people.

For UK gardens, where outdoor space can often be limited, getting the proportions right is particularly important. This guide explains the most common pergola sizes, what each is best suited to and how to work out which size will work best for your garden.

Start with how you want to use your pergola

Before choosing dimensions, think about what you want to do underneath it.

A pergola used for two people enjoying coffee in the morning needs considerably less space than one intended for family dinners and entertaining friends.

Consider whether your main purpose will be:

• Outdoor dining
• Relaxing and lounging
  
• Entertaining
• Creating a sheltered seating area
• Covering an existing patio
• Extending your home's living space
• A combination of dining and seating

It can be helpful to choose your furniture first, or at least have an idea of its dimensions, before deciding on the pergola.

A useful rule: don't plan around the empty floor area. Plan around the finished space.

Common aluminium pergola sizes

There is no single perfect pergola size. The right choice depends on your garden, furniture and how many people you want to accommodate.

The most common sizes include:

Exact dimensions and available sizes vary between manufacturers, so always check the individual product specifications before planning your installation.

3m × 3m pergola

A 3m × 3m pergola is one of the most versatile choices for a smaller or medium-sized garden.

With 9 square metres of floor area, it can create a defined outdoor room without dominating the garden.

It's particularly well suited to:

• A four-person dining table
• Two comfortable lounge chairs
• A compact outdoor sofa
• A small seating arrangement
• Smaller patios and terraces

If you're considering a 3m × 3m pergola, remember that the furniture itself can take up more space than you might expect.

For example, a four-person dining set may fit comfortably, but adding a large sofa, coffee table and additional chairs could make the space feel crowded.

Best for: homeowners looking for a defined outdoor space without using a large proportion of the garden.

View our 3m × 3m Aluminium Pergolas

3m × 4m pergola

A 3m × 4m pergola gives you another metre of length, but that extra space can make a significant difference to how you arrange your furniture.

With 12 square metres of floor area, there's more opportunity to create separate areas for dining and relaxing.

For example, you might position:

• A dining table at one end
• A sofa and coffee table at the other
• A dining and lounge arrangement side by side
• A larger outdoor sofa with occasional chairs

This size can work particularly well on longer patios or gardens where a 3m × 3m structure feels slightly restrictive.

Best for: families, regular outdoor dining and homeowners who want more flexibility without moving into a very large structure.

View our 3m × 4m Aluminium Pergolas

4m × 4m pergola

A 4m × 4m pergola provides 16 square metres of space, giving you considerably more flexibility when arranging furniture.

This can be a good choice if entertaining is an important part of how you use your garden.

You could accommodate a larger dining table alongside a separate seating area, or create one generous outdoor lounge.

The additional width also means furniture doesn't necessarily have to sit directly against the edges of the structure.

Best for: larger gardens, entertaining and homeowners who want their pergola to function as a genuine outdoor living space.

View our 4m x 4m aluminium pergolas

Don't forget the height

When choosing a pergola, footprint isn't the only measurement worth considering.

Look at:

• Overall height
• Eaves height
• Clearance beneath the beams
• Position of the roof when open
• Position of the roof when closed

This becomes particularly important if you're positioning the pergola close to your house or another structure.

You'll also want to consider the proportions of the pergola in relation to the garden. A very large structure in a small garden can feel imposing, while a small pergola in a large garden may look lost.

The aim is to create something that feels integrated into the space.

How much space should I leave around a pergola?

It's tempting to measure the exact area available and choose the largest pergola that will fit.

We wouldn't recommend doing this without considering the space around the structure.

Think about:

Access

You'll need enough room to comfortably walk around the pergola and access your garden.

Doors and windows

If the pergola is positioned near your house, make sure doors can open freely and that you're not obstructing important windows.

Garden furniture

Allow room for chairs to be pulled away from a dining table and for people to move around comfortably.

Maintenance

You'll also need access to the structure for cleaning and maintenance.

Neighbouring boundaries

Consider how close the structure will be to neighbouring properties and whether its position affects privacy or planning considerations.

How to measure your garden for a pergola

Before ordering, measure the proposed location carefully.

You'll need to know:

1. The maximum width available.
2. The maximum depth available.
3. The available height.
4. The distance to property boundaries.
5. The position of doors and windows.
6. The position of drains, manholes and other fixed features.
7. The location of existing furniture or landscaping.

Don't measure just the patio.

Look at the entire area and think about how the pergola will interact with the rest of your garden.

A simple way to visualise the size

One of the easiest ways to understand how a pergola will feel is to mark out the proposed footprint before buying.

Use string, masking tape or temporary garden markers to create a rectangle matching the external dimensions of your chosen pergola.

Then place your furniture inside the area.

Try sitting around the table. Pull the chairs out. Walk between the furniture and the edges.

It can be surprising how different 9m² or 12m² feels once it's occupied.

If you're unsure between two sizes, this simple exercise can make the decision much easier.

Think about the furniture before the pergola

Your furniture should influence the size you choose.

For example, a large corner sofa might look fantastic beneath a 3m × 3m pergola in a photograph, but the combination may leave little room to move around it.

Before buying, measure:

• Sofa width and depth
• Dining table dimensions
• Chair footprint
  
• Planters
• Any other permanent items

Remember to allow space for people to actually use the furniture.

A dining chair needs to be pulled away from the table. A reclined lounge chair needs more space than a dining chair. A large corner sofa may take up considerably more floor area than its photographs suggest.

Choosing a pergola size for a small UK garden

A smaller garden doesn't necessarily mean you have to give up on the idea of a pergola.

In fact, a well-proportioned pergola can make a smaller garden feel more purposeful by creating a defined destination.

For a compact garden, consider:

• A 3m × 3m pergola
• Slim-profile furniture
• Built-in or compact seating
• A smaller dining table
• Vertical planting around the structure
  

Avoid trying to fit too much underneath it. The most successful smaller pergola spaces tend to feel considered rather than crowded.

Arbora Collection’s 3x3m pergolas

Choosing a pergola for a large garden

With more space available, you have greater freedom.

A larger pergola can become the centrepiece of an outdoor living area, with separate zones for dining, relaxing and entertaining.

You could consider:

• A large dining table
• Outdoor sofas
• Lounge chairs
• A barbecue
• Outdoor kitchen
• Planters
• Lighting
• Privacy screens

Should my pergola be attached to the house?

This depends on the layout of your garden and how you intend to use the space.

A wall-mounted pergola can work well when you want to create a direct extension of the living space immediately outside the house.

A freestanding pergola gives you more freedom over its position and can create a separate destination further into the garden.

Consider where you naturally spend time, how you move between the house and garden and whether you want the pergola to feel like an extension of the house or a separate outdoor room.

View our Freestanding Pergolas

Does pergola size affect planning permission?

Size and position can be relevant to planning requirements, but you shouldn't assume that there is one simple size threshold that applies to every pergola.

In England, certain garden structures can fall within permitted development rights if all relevant conditions and limitations are met. These include restrictions relating to height, location, the proportion of land covered and whether the property is listed or on designated land. Planning Portal guidance states, for example, that a structure within two metres of the boundary can be subject to a 2.5m maximum height.

Planning Portal also specifically notes that a pergola can fall under permitted development where the relevant conditions and limits are met.

However, planning rules differ across the UK, and additional restrictions can apply to properties such as listed buildings or homes in designated areas. The guidance above relates to England; Wales has a different planning regime.

If you're unsure, check with your local planning authority before ordering or installing your pergola.

What size pergola is best for outdoor dining?

For outdoor dining, think about the table first.

A four-person dining table can work well beneath a 3m × 3m pergola, provided the rest of the furniture arrangement is relatively compact.

If you regularly host larger gatherings, a 3m × 4m or larger pergola gives you more freedom around the table and makes it easier for people to move around.

The important measurement isn't simply the table itself. Allow for chairs to be pulled out and for people to walk behind them.

What size pergola is best for a sofa?

A sofa arrangement generally needs more space than a dining table because of the depth of the furniture and the additional space occupied by coffee tables and occasional chairs.

For a compact sofa arrangement, 3m × 3m can work well.

For a larger corner sofa or a combination of sofa and chairs, consider a larger footprint such as 3m × 4m or 4m × 4m.

If you're planning to include both a dining area and a lounge area, a larger pergola will usually give you much greater flexibility.

 

What if I'm between two pergola sizes?

If you're deciding between two sizes, don't automatically choose the larger one.

Ask yourself:

• Will I use the additional space?
• Does the larger size overwhelm my garden?
• Can my patio or foundation accommodate it?
  

If the larger pergola allows you to use the space in a completely different way, it may be worthwhile.

Choosing the right size for your lifestyle

Ultimately, the right pergola size comes down to how you want to use your garden.

A 3m × 3m pergola can create a beautiful and practical outdoor dining or seating area without taking over a smaller garden.

A 3m × 4m structure offers more flexibility and can work particularly well when you want to combine dining and relaxing.

Larger pergolas can create much more generous outdoor living spaces, but they need to be considered carefully in relation to the proportions of your garden and home.

Take your measurements, mark out the space and think about your furniture before making a decision.

The best pergola is one that makes your garden feel more usable, not simply one that occupies the most space.

If you're still exploring your options, our Complete Guide to Buying an Aluminium Pergola in the UK covers everything from materials and features to installation, costs and what to look for before you buy.

Find the right aluminium pergola for your garden

At Arbora Collection, we select UK-made aluminium pergolas designed with British gardens and outdoor living in mind.

Whether you're looking to create a compact space for morning coffee, a comfortable area for family dining or somewhere to entertain throughout the summer, choosing the right size is the first step towards making the most of your garden.

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Frequently Asked Questions

Is a 3m × 3m pergola big enough?

For many homeowners, yes. A 3m × 3m pergola provides 9m² of covered floor area and can comfortably accommodate a compact dining set or lounge arrangement. The furniture you choose will have a significant impact on how spacious it feels.

Is a 3m × 4m pergola better than a 3m × 3m?

Not necessarily. A 3m × 4m pergola gives you an additional 3m² of floor area and more flexibility, but a 3m × 3m may be better proportioned for a smaller garden.

What is the most popular pergola size?

There isn't one universal size that is right for every garden. 3m × 3m and 3m × 4m are popular footprints because they provide useful outdoor living space without requiring a particularly large garden.

How much furniture can fit under a 3m × 3m pergola?

A 3m × 3m pergola can accommodate a compact dining or seating arrangement, but the exact amount depends on the dimensions of your furniture. Always measure your furniture rather than relying on the pergola dimensions alone.

How close can a pergola be to a boundary?

This depends on the structure, its height, location and the planning rules that apply to your property. In England, Planning Portal guidance states that certain outbuildings within two metres of a boundary are subject to a maximum height of 2.5m under permitted development rules.

Do I need planning permission for a 3m × 3m pergola?

Not necessarily. The footprint alone doesn't determine whether planning permission is required. Other factors including height, position and property type can be relevant. Check the current rules applying to your property before installation.