You're standing in the garden, trying to work out what size trampoline will actually fit. Or you've measured already and now you're not sure which size suits the children using it. Either way, the question is the same: what size do you need?
Here's how to work through it.
Step one: measure your garden
The first number you need is not the trampoline size — it's the clear space you have available. Measure the area where the trampoline will actually go, accounting for everything around it: the patio, the shed, planted beds, the fence on each side. The usable patch is usually smaller than the garden overall.
Once you have that measurement, apply the clearance rule. A trampoline needs at least 1 metre of clear space around the entire frame — that's 1 metre between the outer frame and any fence, wall, tree, or structure. Not touching, not almost touching: 1 metre of clear air on all sides.
Here's what that looks like in practice:
- 6ft trampoline: frame is 6ft across. Needs roughly 9-10ft (around 3 metres) of clear space in every direction.
- 8ft trampoline: needs roughly 11-12ft (about 3.5 metres) clear space.
- 10ft trampoline: needs roughly 13-15ft (about 4-4.5 metres) clear space.
- 12ft trampoline: needs roughly 15-17ft (about 4.5-5 metres) clear space.
- 14ft trampoline: needs roughly 17-19ft (about 5-6 metres) clear space.
These apply in every direction from the centre — so for a round trampoline, you need that clear space north, south, east, and west. It's not just the length of the garden that matters; the width does too.
If you want a more detailed breakdown, our trampoline size guide has a full table of measurements for every size we sell.
Step two: think about who will use it
Garden space sets the upper limit of what you can buy. Within that limit, the right size depends on the age and number of children who'll actually be using the trampoline.
Children grow fast. A 6-year-old and an 11-year-old have very different relationships with a trampoline. The decision is partly about right now and partly about whether the trampoline will still be appropriate in three or four years.
Ages 3-6: A 6ft trampoline is built for this group. The bounce area is right, the weight limits are appropriate, and it fits in small gardens. The limitation: children outgrow it noticeably by 7 or 8. If you're buying for a 5-year-old with room for an 8ft, the 8ft is the better investment.
Ages 5-9: Our 8ft trampoline range works well here. It fits in compact gardens, handles one child well through the primary school years, and typically supports 75-100kg. A sensible middle option when space is limited.
Ages 8 and up: This is where 10ft becomes the minimum worth considering. Our 10ft trampoline range suits children from 8 into early secondary school and gives noticeably more jumping room. If siblings will share it, consider whether a 12ft is achievable — two children bouncing simultaneously on a 10ft is noticeably more crowded than on a 12ft.
Ages 10 and up, or siblings sharing: Our 12ft trampoline range is worth the extra garden space if you can accommodate it. More bounce area, higher weight limits (125-150kg), and a longer useful lifespan into the teenage years.
Teenagers, or families who want the trampoline to last into late teenage years: If the garden fits a 14ft and the budget allows, our 14ft trampoline range gives a noticeably better jumping experience for older users. The weight capacity typically reaches 150kg or above, which is practical for teenagers and adults.
Step three: pick your size
With the garden measurement and the age context, you can now make the call. The logic is straightforward:
Take the largest size that fits in your available clear space. Then check it's appropriate for the age group. If it is, that's your size. If the largest that fits is smaller than ideal for the age — for instance, an 8ft fits and you're buying for a 12-year-old — go with it but be aware the useful lifespan may be shorter than with a larger option.
Where people go wrong is buying the size they want rather than the size that fits. A 14ft trampoline that needs 18ft of clear space but has only 14ft available is a problem — not just from a safety perspective but from a practical one. A trampoline crammed against a fence is going to get damaged, and it creates a hazard for children near the enclosure edge.
The other common mistake is buying too small for the child's age because the smaller option is cheaper. A 6ft bought for a 7-year-old will feel small within a year. The price saving on day one rarely feels worth it by year two.
The most popular sizes
If you look at what families actually buy, 10ft and 12ft are by far the most common. The reason is that they fit most medium-to-large gardens and suit the age range where most children are when parents are thinking about buying — roughly 7 to 12.
The 10ft is the default choice for many families. It's the right size for a child aged 8-12 with a standard-sized suburban garden. The 12ft is increasingly chosen by families who have the space for it, particularly once they've measured properly and found a 12ft is actually achievable. Both are good choices; the 12ft gives more of everything.
For families with genuinely compact gardens, the 8ft is the practical answer. It isn't a consolation prize — it's a properly designed trampoline for children in the 5-9 age range, and it does what it's supposed to do.
What about rectangular?
Round trampolines are the mainstream option, and for most families they're the right one. The bounce is self-correcting — springs pull the jumper toward the centre — which suits younger children and general garden use.
Rectangular trampolines have a different bounce profile: higher, flatter, more even across the full mat surface. They work better in narrower gardens because the footprint is longer than it is wide. They suit older children and anyone with a gymnastics or dance background who wants more control over their bounce.
Our rectangular trampoline range is worth a look if your garden is long and narrow or if the primary user is a teenager who wants more than a standard round trampoline offers.
Frequently asked questions
What's the smallest garden that can take a trampoline?
A 6ft trampoline needs about 9-10ft of clear space in every direction — so a garden section that's at least 9-10ft wide and 9-10ft deep with nothing in the way. In reality, many smaller terraced gardens can fit a 6ft with care. Measure precisely before ordering.
What size trampoline is best for a 10-year-old?
A 10ft or 12ft, depending on your garden. By 10, most children find an 8ft noticeably constraining. The 10ft gives them proper room to jump, and a 12ft gives even more. If your garden accommodates either, the 12ft is the better long-term buy for a child of that age.
Do adults fit on garden trampolines?
Check the weight limit on the specific model. Many 10ft and 12ft trampolines are rated to 100-150kg, which most adults fall within. What limits adult use is usually the enclosure height (designed for children, some adults find it restrictive) and the bounce — which is calibrated for lighter users. Adults occasionally jumping with children is generally fine; adults using it as a primary fitness tool need to look at models specifically rated for that.
What's the difference between a 10ft and a 12ft in practice?
The jump mat on a 12ft is around 8.5ft across versus 7ft on a 10ft — roughly 47% more bounce area. In practice that means more room to jump, more space when siblings share it, and a more substantial bounce experience for older children and teenagers. The difference is noticeable. If the garden fits both, most families who have both sizes say they'd go 12ft again.