Garden · Sizing
Patio & Decking Sizes Explained
By the Nest & Yard editorial teamUpdated 2026-08-094 min read
Our pick: the Wet & Forget Rapid Action Outdoor Treatment, Moss, Mould & Algae Remover, 5 Litre — the best Patio & Decking we tested, from £20.15.
Choosing the right size patio or decking set for your garden can feel overwhelming, with so many measurements and terms thrown around. This guide breaks down how sizes are typically described – from square metres to linear lengths – and helps you determine what’s appropriate for your outdoor space, whether it's a compact balcony or a larger family area. Before you start shopping on Amazon UK for options like decking oils and cleaners, understanding these dimensions is key to ensuring a perfect fit and a long-lasting investment in your garden.
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Currently unavailable
Pros
- Removes dirt, algae and mildew to restore decking colour
- Opens wood pores ready for oil or stain
- Covers up to 25 square metres per 5L
Cons
- Needs a stiff brush and rinsing for best results
#2 Pick
Wet & Forget Rapid Action Outdoor Treatment, Moss, Mould & Algae Remover, 5 Litre- Liquid Concentrate
£20.15
Pros
- Spray and leave — no scrubbing or rinsing needed
- Bleach-free formula is safe for plants nearby
- One bottle makes up to 30L of solution
Cons
- Results take days to weeks to appear
#3 Pick
Ronseal Decking Oil Natural Pine 5L- Decking Protection
£22.95
Pros
- Nourishes and protects wood from cracking and splitting
- Natural pine tint enhances timber grain
- One coat covers up to 20 square metres
Cons
- Needs dry weather to apply and cure properly
£38.78
Pros
- Soaks into timber for long-lasting weatherproofing
- Enhances natural wood grain
- 5L covers a good-sized deck
Cons
- Timber decking needs reapplying every 1-2 years
FAQ
What does 'Square Meter' mean and why is it used for patio sizes?
Square meters (m²) are the standard unit for measuring area in the UK, representing one square metre – a space 1 metre by 1 metre. This provides an accurate way to determine how much outdoor space you’re purchasing when considering patios and decking.
What's the difference between 'Square Feet' and 'Square Meters'?
While both measure area, square feet (ft²) is a US measurement system, whereas square meters (m²) are used in the UK. Converting between them requires multiplying by 10.764 – ensuring you’re comparing accurately.
My patio is roughly rectangular; how do I calculate its size?
Measure the length and width of your patio area in metres, then multiply these two measurements together to determine the square metre (m²) measurement. This will give you a precise figure for calculating the space you have.
I'm planning a small patio for one or two people; what size would be suitable?
For a smaller seating area, an 8m² to 12m² patio is generally sufficient – this allows enough room for a table and chairs without feeling cramped. Consider the shape too; a square or rectangular space will often feel more efficient than an oddly shaped one.
What size patio would be ideal for a family of four?
A family of four typically needs around 16m² to 24m² for comfortable outdoor dining and lounging. This provides ample space for furniture, children's play areas, and occasional guests – ensuring everyone has room.
How do I measure my deck or patio accurately?
Use a measuring tape to carefully measure the length and width of your area in metres. Ensure you are measuring from corner to corner and take multiple measurements for accuracy, especially on uneven ground.
What's a 'Tiered Decking' size typically measured as?
Tiered decking is often described by its overall footprint – generally between 18m² and 24m². However, the height of each tier also impacts usable space, so consider both measurements.
I have a small balcony; what’s the smallest patio size I could realistically install?
For a very small balcony, you’d likely be looking at around 6m² to 8m² – enough for a single chair and small table. Consider the depth of your balcony when planning your purchase.
Does the shape of my patio area affect how much space I actually have?
Yes, significantly! A square or rectangular patio will generally feel more spacious than an irregularly shaped one, even if they are the same overall area. Optimise for a simpler shape to maximise usable space.
What should I consider when measuring outdoor space before buying decking or paving?
Always factor in access routes and any existing features like trees or fences when determining your patio size. Ensure you have enough room for furniture and movement around the area – don’t overcrowd it!
In depth
When considering patio and decking sizes, it’s easy to get overwhelmed by the terminology. Manufacturers and retailers use various measurements – square meters, square feet, linear metres – and understanding what these actually represent is key to getting a space that truly suits your needs and your garden. The most common initial measurement you'll encounter is in square meters (m²). This represents the area of a rectangle or square, calculated by multiplying its length by its width. However, many manufacturers also list dimensions in square feet (ft²), which are derived from converting metres to feet (approximately 3.28 ft = 1 metre). It’s vital to be aware of this conversion when comparing sizes across different listings – a deck listed as 4m x 6m equates to approximately 24ft x 32ft.
The term ‘linear meter’ is often used, particularly for decking boards themselves. This refers to the length of one board, typically around 2.4 or 3 metres. When calculating the total amount needed for your deck, you'll need to factor in the width of the deck (usually expressed in m²), and then divide that area by the linear metre length of the boards to determine how many boards you’ll require. Don’t forget to add a little extra – around 10% – to account for cuts and wastage during installation, which is standard practice with any DIY project. It's also worth noting that some manufacturers will quote ‘board width’, this is the actual width of one decking board, typically between 125mm and 200mm.
Determining the right size patio or deck really hinges on assessing your household’s usage patterns and the available space. A small urban balcony might comfortably accommodate a 1.8m x 2.4m (2.16 m²) area – enough for a bistro set and perhaps a couple of chairs. For a family with young children, you'll likely want something considerably larger; a 3m x 4m (12 m²) or even 4m x 5m (20 m²) deck would provide ample space for outdoor dining, play, and relaxing. Consider the number of people you typically entertain – a larger space is essential if you regularly host barbecues or gatherings. Think about what activities you want to be able to do on your patio; will you need room for an outdoor sofa, a hot tub, or perhaps even a small paddling pool?
A very common mistake among homeowners when estimating patio and decking sizes is simply measuring the *footprint* of the area they intend to use without accounting for furniture. It’s easy to visualise a large expanse of paving or decking, but then realise that once you add in chairs, tables, loungers, and potentially an outdoor kitchen, the usable space shrinks dramatically. Take accurate measurements of your furniture – length, width, and height – and factor those dimensions into your calculations. A good rule of thumb is to allow at least 1.5m between seating areas and any other features on the patio to ensure comfortable movement.
For larger gardens, you’ll likely want a deck that seamlessly integrates with the surrounding landscape. Consider the orientation of your garden – south-facing decks receive the most sunlight, making them ideal for outdoor dining during the summer months. However, they can also overheat in the height of summer, so shade structures such as pergolas or umbrellas may be beneficial. A rectangular deck offers maximum space and versatility, while a square deck is simpler to construct and often more cost-effective. Think about how you want to use the area – a long, narrow deck might suit a garden with an awkward shape, whereas a larger, more open deck would work well in a spacious backyard.
When planning your patio or decking project, always prioritise accurate measurements. Don’t rely on guesswork; take detailed measurements of your space and carefully consider your needs. It's far better to slightly overestimate than to find yourself with an area that is too small for your requirements. Furthermore, remember to account for access – you'll need sufficient space around the perimeter of the deck to allow for comfortable movement and maintenance. Finally, don’t forget to check local planning regulations before starting any construction work; some areas require planning permission for decking projects exceeding a certain size or height.
The Nest & Yard editorial team
Written and reviewed by our UK-based team of home improvement and gardening writers, who research specs, pricing and customer reviews before every recommendation. Reviewed and updated on 2026-08-09.