The size question comes up in almost every first conversation we have with a buyer, and the honest answer is that it depends less on total budget and more on three practical factors: your plot's access, what you're storing or building, and how the unit will eventually leave the site if your plans change.

Footprint and internal space

A 20ft standard container gives you roughly 33 cubic metres of enclosed space on a footprint of about 6 by 2.4 metres. A 40ft unit doubles the length to around 12 metres while keeping the same width, for roughly 67 cubic metres. That doubling matters more than it sounds — a 40ft unit isn't just "more storage," it changes what's structurally practical to build inside it, from a two-room office layout to a full studio apartment.

Cost per square metre

Because a 40ft unit shares one set of corner castings, one roof structure and one floor system across double the length, the steel and fabrication cost per square metre is consistently lower than a 20ft unit of equivalent condition. If your project can use the extra length, a single 40ft box is almost always cheaper per usable square metre than two 20ft boxes covering the same area.

Transport and site access

This is where the calculation flips for a lot of Kenyan sites. A 20ft container can be manoeuvred by a smaller flatbed and craned or winched into tighter urban plots, narrow access roads, or sites without a clear straight-line approach. A 40ft unit needs a longer rigid trailer, a wider turning circle, and enough clearance to reverse or crane it into position — manageable on most commercial and peri-urban plots, but worth checking before you commit to the larger size on a constrained urban lot.

Structural trade-offs for conversions

If you're converting rather than just storing, length changes what's viable. A single 20ft unit comfortably fits one room plus a small wet area — a guard house, a site office, a compact retail kiosk. A 40ft high cube gives you room for a proper studio layout, a two-workstation office, or a classroom with a separate storage nook, without needing to weld two units together and manage the seam.

Our rule of thumb

  • Choose 20ft if your plot access is tight, your use case is single-purpose (storage, a guard post, a small kiosk), or you want the lowest possible entry cost.
  • Choose 40ft (or 40ft high cube) if you're building anything with more than one functional zone, your site can accommodate a longer trailer, and cost per square metre matters more than unit price.
  • Choose multiple units only when your layout genuinely needs separate structures — combining containers adds welding, sealing and reinforcement cost that a single larger unit avoids.

If you're still unsure, send us your plot dimensions and intended use on WhatsApp — we can usually tell you which size fits within a few questions.