Deck Size Calculator
Tell the calculator how many people you want to seat for meals, whether you need room for a grill or hot tub and how many sun loungers. It adds up the space for each and suggests a deck size.
- Sized by use
- Dining, grill, loungers
- Metres and feet
Allows 20% extra for walkways and steps. Add more if the deck is also a route to the garden.
Size a deck for what you will do on it, not for the space you have. A deck that is too small feels cramped once a table and chairs are out. One that is too big costs more and can overwhelm the garden. Adding up the space each activity needs gives a size that works.
Deck size chart
Typical layouts. Search for a use.
| Use | Area (m²) | Area (ft²) |
|---|---|---|
| Bistro table for 2 | 4 | 43 |
| Dining for 4 | 6 | 65 |
| Dining for 6 | 8 | 86 |
| Dining for 8 | 9.4 | 101 |
| Grill and prep | 3 | 32 |
| Two sun loungers | 5 | 54 |
| Hot tub | 6 | 65 |
Areas include room to move around. A hot tub also needs a deck strong enough for about 2 tonnes when full.
Diners and deck size
With a grill and two loungers. Slide the number of diners.
The plan shows each zone. Dining is usually best near the house door, loungers in the sunniest corner.
How to size a deck
Zone by zone. Step through it.
List the uses
Dining, cooking, relaxing.
A deck looks best in proportion to the house. Many designers keep it under about 20% of the house footprint.
Small, medium or large deck
Common sizes. Compare them.
A table for four or two loungers.
Dining for six plus a grill.
Dining, loungers and a hot tub.
Raised decks over 300 mm high may need planning permission in the UK, and railings above about 600 mm.
Before you build
Planning. Tick each item.
Tick each item as you go.
Watch where the sun falls at the times you will use the deck. Evening sun matters most for dining.
What you get
Deck sizing. Each tile explains one result.
m² and ft².
Width × depth.
Zone area.
Zone area.
Space to move.
The suggested size uses a 3:2 shape. Adjust it to fit the garden, keeping the total area.
Frequently Asked Questions
No question matches that search.
How big should a deck be for 6 people?
About 8 m² for dining alone, or about 19 m² with a grill, two loungers and room to walk round.
What size deck for a table and chairs?
At least 3 × 3 m for a table for four.
How much space does a hot tub need?
About 6 m² including room around it.
What is a good deck size?
Most garden decks are 10 to 20 m².
How deep should a deck be?
At least 3 m for dining comfortably.
How big is a 12 × 16 ft deck?
About 17.8 m².
Do I need planning permission?
In the UK, for decks over 300 mm high or covering more than half the garden.
A deck that fits your life
Add up the space for how you will use it, allow room to move and pick a shape for your garden. The result is a deck that feels right, not too cramped and not too big.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.