20ft Shipping Container Dimensions: Complete Spec Guide for Canada

By Christian LeBlanc, second-generation operator, and Paul LeBlanc, owner, Van Blanc Ent. Inc.

Reading Time: about 16 minutes

Every shipping container project starts with the same question: “Will it actually fit my stuff, and will my stuff fit my space?” For a 20ft container in Ontario, the answer depends on five numbers in five different unit systems, the door opening (which is smaller than the interior), and the foundation you have prepared. This guide walks through all of it: the spec, the math, the cost, and the on-site reality of a 20ft container delivered from our Brantford yard.

Van Blanc has been delivering 20ft containers across Ontario since 1995. The 20ft is our most-delivered size, by volume, every year, across every customer type from cottage country to industrial parks. Most buyers think the question is “what are the dimensions” but the real question is “do those dimensions match my use case.” This guide answers both.

All five units in one table: feet, metres, cm, mm, inches

Buyers ask for 20ft dimensions in different unit systems depending on who taught them measuring. Trades folks often default to feet and inches. Engineers and Europeans default to millimetres. Most homeowners use metres and feet interchangeably. Here is every dimension a 20ft Standard container has, in every common unit system, on one page.

These dimensions are fixed by ISO 6346:2022 (Freight container coding, identification, marking) and ISO 668 (Freight containers, Classification, dimensions and ratings). Every manufacturer worldwide (CIMC, Singamas, Maersk Container Industry, Daikin, CXIC) builds to the same external numbers within a 5mm tolerance. Internal dimensions vary by 5-10mm between manufacturers depending on wall corrugation depth and floor thickness, but the external envelope is constant. This is what makes containers globally interchangeable on ships, trains, and trucks.

Why interior is 16cm shorter than exterior (and what that costs you)

The external length of a 20ft container is 6.058m. The internal length is 5.898m. That is 16 cm of length you lose to the steel structure. Specifically, the corrugated end walls and the door frame structure. Same story on the width: 2.438m external becomes 2.352m internal (an 8.6 cm loss to the corrugated side walls). And height: 2.591m external becomes 2.393m internal (19.8 cm lost to the corrugated roof and floor framing).

Why this matters operationally:

• Buying a 20ft to hold an exact-length object. A jet ski or small powerboat at 5.9m long fits inside the 5.898m internal length with literally no margin. Anything 6.0m+ does not fit a 20ft. You need a 40ft.
• Planning a conversion floor plan. The usable floor is 5.898m x 2.352m = 13.88 m². Drawings that use the external dimensions overestimate floor space by 14 percent. Always design from internal dimensions.
• Calculating loaded weight distribution. The 16cm of structure at each end is steel; the cargo only loads the internal length. Heavy cargo at the door end concentrates weight on the corner castings rather than across the floor.

Fork pocket dimensions: how forklifts and cranes lift the container

Every 20ft ISO container has two fork pockets built into the bottom side rails for forklift handling, plus four corner castings for crane and tilt-deck lifting. These are not optional features. They are how the container physically moves between locations after delivery.

The fork pocket spacing is what determines which forklift can lift a 20ft container. A standard 8,000 lb warehouse forklift with 1.2m forks cannot reach the second pocket from the centre side. You need a heavy industrial forklift with 2.4m+ forks (typically 15,000 lb+ capacity rated machine) or a tilt-deck truck for delivery and relocation. This is why most Ontario buyers use tilt-deck for both delivery and any subsequent relocation rather than trying to find a forklift big enough.

The four corner castings (one at each top corner and one at each bottom corner) accept ISO twistlocks for crane lifting. Crane lifting requires a spreader bar that engages all four top corner castings simultaneously. Spreader bars are standard equipment at any crane operator in Ontario who handles containers, so the rental is usually bundled into the crane operator’s rate rather than billed separately.

Door opening dimensions: the loading constraint

The cargo door at the rear of every 20ft container is slightly smaller than the internal dimensions because the door frame is welded into the container shell with a seal lip around the perimeter.

The door opening height is roughly 11 cm less than the internal height because of the top door frame seal. For loading equipment, that 11 cm decides what fits. A pallet of stacked drywall sheets at 2.0m loads through either size. A typical 2.1m tall industrial pallet still loads through Standard. A small forklift at 2.2m height needs the High Cube door clearance. Most ATVs and motorcycles clear easily. A full-size pickup needs the High Cube. A standard sedan or compact SUV fits the Standard.

What actually fits inside a 20ft container

The “what fits” question gets a different answer for every cargo type. Here is the practical Ontario buyer reality for the most common loads.

Weight, payload, and what your driveway has to handle

A 20ft container has three weight numbers stamped on its CSC plate:

• Tare (empty) weight: 2,200 to 2,300 kg (4,850 to 5,070 lb)
• Maximum payload: 21,750 kg (47,950 lb)
• Maximum gross weight: 24,000 kg (52,910 lb) per ISO 1496

For Ontario buyers using the container for storage or conversion, the operational number is the tilt-deck delivery weight: empty container at 2,250 kg plus the tilt-deck truck at about 11,500 kg = roughly 13,800 kg combined road weight on your driveway during the 20-30 minute delivery window. Most concrete and asphalt driveways handle this without issue. Soft topsoil, gravel without proper base, and uninspected wooden bridges on rural roads may not. Our deeper guide to shipping container weight and delivery weight handling covers all four sizes plus Ontario road-haul limits.

The 20ft is the easiest size to deliver in Ontario because of this lower combined weight. Tight residential lots, suburban driveways, and most cottage country access roads handle a 20ft delivery without site preparation beyond a level pad.

Standard vs High Cube: when 30 cm matters

The only spec difference between a 20ft Standard and a 20ft High Cube is height. Both share the same 6.058m length and 2.438m width. The Standard is 2.591m external (8’6″) and the High Cube is 2.896m external (9’6″). Internally that translates to 2.393m versus 2.698m, a 30 cm difference.

The 30 cm matters in three scenarios:

1. Conversions with finished interior. A 3-inch closed-cell spray foam ceiling and a finished framing layer eat 8-10 cm of headroom. Standard at 2.393m drops to about 2.30m of usable headroom. High Cube at 2.698m drops to 2.60m. For office, workshop, or living conversions where tall residents need clearance, the High Cube is worth the premium.
2. Stacked pallets with tall items. 1.3m to 1.5m pallets stacked 2-high need at least 2.60m of usable height. Standard at 2.39m forces single-layer loading on those pallets. High Cube enables 2-high.
3. Reefer applications. Refrigeration units eat 15-20 cm of interior height. A reefer in Standard barely clears most cargo; a reefer in High Cube preserves usable volume.

For pure dry storage of household goods, equipment, or boxes under 1.5m tall per stack, the Standard is fine. Buyers should not pay the High Cube premium unless they have a specific use that needs the height. Our High Cube vs Standard breakdown covers when the upgrade pays for itself.

Site preparation: concrete, gravel, blocks, or grade?

This is one of the most-asked questions from first-time 20ft buyers, and Google’s People Also Ask shows it directly: “Do you need a concrete slab for a shipping container?” and “Should shipping containers be on the ground or blocks?” and “What is the best base to put a shipping container on?”

The short answer: blocks, cribs, or piers on a stone pad, not concrete, not bare ground. Here is the longer answer.

Direct on grade (do not do this)

Setting a 20ft directly on grass or topsoil traps moisture against the underside steel. The container starts corroding from the underside within months. Plants grow into the corrugations. Freeze-thaw cycling shifts the corner castings unevenly. We have seen 20ft containers placed on grass in 2018 show significant underside corrosion by 2024. Always elevate.

Stone pad with corner blocking (the standard Ontario approach)

Excavate the footprint 15 cm deep, lay 10-15 cm of compacted 3/4-inch clear stone, set four concrete deck blocks or pressure-treated 6×6 timber cribs at the corner casting positions, and place the container on the cribs. This is the lowest-cost option, driven mostly by how much stone the site needs and whether you do the labour yourself, and it is what about 70 percent of Ontario 20ft deliveries land on. The container is removable (resaleable, relocatable) and the install survives Ontario freeze-thaw for decades.

Sono-tube piers (better for sloped or soft-soil sites)

Four to six 8-inch diameter concrete piers poured 1.2m deep (below the Southern Ontario frost line) with a steel pin and bearing plate on top. This costs more than a stone pad because of the concrete, the rebar, and the deeper excavation, but it is the right answer for sloped sites, soft topsoil, or any installation where the container will not be relocated.

Full concrete pad (only if you need it)

A poured concrete pad sized to the 20ft footprint with frost-protected footings. This is the most expensive base by a wide margin, since it adds formwork, rebar, and a full concrete pour, and it is best for permanent residential installations or any build where the container is becoming part of the home architecture. Rarely needed for storage.

Real Ontario 2026 cost by grade

20ft container pricing in Ontario splits by grade. The grade is what determines remaining service life, cosmetic condition, and how the container has lived its prior life.

Delivery from our Brantford yard is priced by distance: the shortest add-on is for nearby Southern Ontario addresses, more for cottage country, and the most for Northern Ontario routes. The turnkey number you pay (container plus delivery) is driven by the grade you choose and how far the tilt-deck has to travel, which is exactly why we quote to your specific postal code rather than posting a single figure.

The PAA question “How much should I pay for a 20 foot container?” has different right answers by use case:

• For general storage: Wind & Water Tight is the sweet spot, giving you a dry, sound box at the lowest sensible grade.
• For occupied conversion (office, workshop): One-Trip makes sense because you avoid prep work and start with clean steel.
• For long-term agricultural or industrial use: Cargo Worthy balances up-front cost against remaining service life.

Used vs new: which grade is worth it?

Google PAA asks this directly: “Are used 20ft containers worth buying?”

For most Ontario use cases, yes. A used 20ft Wind & Water Tight or Cargo Worthy container is built from the same Corten steel as a One-Trip, with the same structural envelope and the same ISO 6346 specs. The differences are cosmetic: paint chips, surface rust patina, minor dents from years of ocean shipping handling. Structurally, a 14-year-old Cargo Worthy container delivered to a Brantford farm has decades of remaining service life if it goes on a properly drained pad.

Three scenarios where new (One-Trip) is worth the premium:

1. The container will be occupied space. Office, workshop, accessory dwelling. The interior steel should be clean, free of repair welds, and dry. One-Trip delivers this; used grades require prep work that often costs more than the price gap.
2. The container is visible from the road or a customer-facing area. Restaurant kiosks, retail pop-ups, residential placements on a visible lot. Cosmetic condition matters and a One-Trip arrives looking new.
3. The buyer plans to resell within 3-5 years. One-Trip containers retain 60-75 percent of purchase price at the 3-year mark; used grades retain 45-60 percent. For short-hold use cases, the One-Trip recovery offsets the premium.

For everything else (storage, farm, construction site, industrial laydown), used grades are the honest right answer. Our new vs used grade explainer walks through every grade in detail.

20ft vs 10ft vs 40ft: matching size to use case

The 20ft is the most-delivered single size in the Ontario market, but it is not always the right size for every job. Here is the honest sizing decision.

The 20ft is the size that works for the most common Ontario use cases because 33 cubic metres of secure dry storage covers the typical household, hobby, contractor, or cottage owner. Above that volume, the math shifts toward 40ft. Below that volume, the 10ft becomes the better size. Our 20ft vs 40ft cost-per-cubic-metre analysis covers the per-volume math in detail.

Frequently Asked Questions

Pick your 20ft container in person at our Brantford yard

If you are about to commit to a container, you should see the container before you buy it. Van Blanc has been delivering 20ft containers across Ontario since 1995. Our four Brantford yards carry over 200 containers at any given time, including a deep stock of 20ft Standard and 20ft High Cube units across all grades. You walk the row, check the corner casts, look at the floor inside, knock on the panels, and pick the exact unit. We are the only vendor in Ontario that lets buyers do this.

We deliver across Ontario in 1 to 3 business days from Brantford. Payment is COD on delivery, no wire transfers, no deposits, no Facebook Marketplace games. Our pricing is honest and quoted to your address, with no mystery fees added at the door. Our reviews are 4.9 stars across 140+ verified buyers. Come walk the yard.

For the full 20 ft versus 40 ft decision matrix with cost-per-cubic-foot math, site requirements, and use-case framework, see our 20ft vs 40ft container Ontario guide.