How to Choose a Container Gym Size? 2026

One of the most common dilemmas our clients have: “I’m looking at these dimensions but I can’t feel whether they’ll be too big, too small or just right.” Square metres on paper and square metres in reality are two different things — especially when we’re talking about a space where you’re going to swing dumbbells and run on a treadmill.

This guide has one goal: help you choose the right size without visiting a showroom.

April 2026 update: We retired 11×3 from the flagship range. It was replaced by 7×5 (35 m², studio-level) — proportions closer to a square, more room for a second cardio piece and a functional zone. The 2026 line is: 7×3, 8×3, 9×3, 6×5, 7×5 and custom.

Decision matrix — where to start

Two questions that decide the choice:

1. How many people will train at the same time?
2. What kit do you want?

The answers lead to a specific model. Here’s the matrix:

Basic kit: rack, bench, free weights, treadmill or bike Extended kit: + cable machine, additional stations, 2 cardio pieces Commercial kit: strength machines, 3+ stations simultaneously, hotel-grade equipment

Gym Box 7×3 — who’s it for?

Floor area: 21 m² Internal dimensions: ~6.6 × 2.7 m after finishing

Fits:

• Compact rack or power rack
• Adjustable bench
• Dumbbells 2–30 kg, Olympic barbell
• Wall bars (new for 2026)
• Mat + pull-up bar

Who’s it for: smallest plots, one person training solo, limited budget. Ideal for strength training “after work” without cardio.

Indicative price: from ~£13,000 net

Gym Box 8×3 — who’s it for?

Floor area: 24 m² Internal dimensions: ~7.6 × 2.7 m after finishing

Fits:

• Multi-function rack with cable system
• Adjustable bench
• Free weights (dumbbells + barbell)
• 1 cardio piece (treadmill or bike)
• Rubber flooring

Who’s it for: one person training solo or a couple who rarely train at the same time. Ideal for strength training without cardio, or with one cardio piece.

What won’t fit: two treadmills, a leg press, a large multi-station rack, 4 people at once.

Indicative price: from ~£15,000 net

Gym Box 9×3 — who’s it for?

Floor area: 27 m² Internal dimensions: ~8.6 × 2.7 m after finishing

Fits:

• Rack with high and low cable attachments
• Bench + free weights
• 2 cardio pieces (e.g. treadmill + bike)
• Stretching mat
• Comfortable bodyweight training zone

Who’s it for: a couple training at the same time, one person with a developed plan and varied equipment. Turn-key package from ~£10,600 gross (Standard).

What won’t fit: a full set of strength machines, 4 people without squeezing.

Gym Box 6×5 — Bestseller 2026

Floor area: 30 m² Internal dimensions: ~5.6 × 4.7 m after finishing

Fits:

• Full strength zone: rack, free weights, cable systems
• Cardio zone: treadmill + bike or cross-trainer
• Functional zone (kettlebell, TRX, boxes)
• Yoga / mobility mat 2×2 m
• Comfortable use by 3 people at once

Who’s it for: families of 3–4, PTs running 1-to-1 or 2-to-1 sessions, clients who value close-to-square proportions (better layout than a “tunnel” 11×3). Most-ordered size in 2026.

Indicative price: from ~£18,000 net

Gym Box 7×5 — studio-level

Floor area: 35 m² Internal dimensions: ~6.6 × 4.7 m after finishing

Fits:

• Full strength zone: rack, free weights, cables, plate-loaded
• Full cardio zone: 2 treadmills + bike or cross-trainer
• Stretching and mobility zone
• Room for mats, TRX, kettle, free-standing pull-up bar
• Comfortable use by 4 people at once

Who’s it for: families, hotels and aparthotels, companies with employee benefits, PTs with mini-groups. Replaces the retired 11×3 — extra width gives a more comfortable layout.

Indicative price: from ~£21,000 net

”I’m torn between X and Y — which one?”

Torn between 7×3 and 8×3

Choose 8×3 if:

• You’re planning cardio (treadmill, bike) — 7×3 gets cramped
• You want a second piece beyond the rack
• You train as a couple even once a week

Price difference ~£2,000 net, but noticeably more comfort.

Torn between 8×3 and 9×3

Choose 9×3 if:

• You have a training partner, even if you rarely train together
• You’re planning a treadmill (running needs free space around)
• You want a stretching zone without folding the equipment away every time

Torn between 9×3 and 6×5

Choose 6×5 if:

• You’re planning to train with 3 people at once
• You care about close-to-square proportions (better for mats, yoga, mobility)
• You want a functional zone with room for a pull-up bar and boxes

Torn between 6×5 and 7×5

Choose 7×5 if:

• You’re using the gym commercially (hotel, PT studio, employee benefit)
• You want two treadmills or treadmill + cross-trainer
• You’re planning 4 people training simultaneously

At 7×5 training becomes a pleasure, not a game of equipment tetris.

How to measure your garden

Before choosing a model, measure the available space on your plot. Key rules:

Minimum distances:

• From the property boundary: min. 1.5 m (check local planning rules)
• From the main building: min. 1.2 m (for access and ventilation)
• In front of the container entrance: min. 1.5 m of clear space (comfortable entry, especially in winter)
• To the side: min. 0.8 m (access for AC and window maintenance)

Practical tip: “Narrow” models (7×3, 8×3, 9×3) have an external width of 3 m and are set up lengthways. “Square” models (6×5, 7×5) are 5 m wide — check you have at least 6.5 m of free width plus length. For 7×5 that’s ~7×6 m of clear ground.

Transport access: The container arrives on a HIAB-equipped lorry or with a crane. You need access for a vehicle ~3.5 m wide and ~12 m long. If your gate is narrow — worth checking before ordering.

Summary

There’s no wrong choice between the models — only a choice that doesn’t match the brief. The rule is simple:

• Solo training, tight budget → 7×3 or 8×3
• Couple, or you want more comfort → 9×3
• Family 3–4, best proportions → 6×5 (Bestseller)
• Studio-level, commercial, hotels → 7×5
• Unusual plot shape or > 35 m² → custom

If you’re in doubt, describe your situation — we’ll tell you which model suits your garden and training needs. We do it free of charge, with no obligation.