Container Specifications: Shipping Container Dimensions, CBM and Weights

The external shipping container dimensions are fixed. A 20ft is 6.058 × 2.438 × 2.591 m (20ft × 8ft × 8ft 6in); a 40ft is the same cross-section at 12.192 m long; a 40ft high cube adds 305 mm of height, at 2.896 m (9ft 6in). Those come from ISO 668 and are the same on every box in the world. What is inside them — internal length and height, cubic capacity, tare and payload — is not fixed, and varies by manufacturer, build year and how the owner has rated the box. This page gives the ISO nominal figures and typical ranges, and tells you where to read the real numbers.

Container specification table — ISO nominal figures

Read the external dimensions as exact and the internal dimensions, cubic capacity, tare and payload as typical. On any live shipment the authoritative figures — tare, max gross, container number — are stamped on the CSC safety approval plate on the left-hand door. If the plate disagrees with the table, the plate is right.

A 40ft is therefore not twice a 20ft in payload — twice the volume, slightly less weight, because both are usually rated to the same 30,480 kg gross and the 40ft eats 1.5 tonnes of it in tare. Dense cargo goes in 20ft boxes; light, bulky cargo in 40ft and high cubes. The high cube buys volume, not weight: the plate rating does not change.

Cubic capacity and why you never load the full CBM

Cubic capacity is internal length × width × height: a 20ft at 5.90 × 2.35 × 2.39 gives 33.1 CBM, a 40ft high cube at 12.03 × 2.35 × 2.69 gives 76.0 CBM. Nobody loads that. Realistic planning figures are roughly:

• 20ft standard — 33 CBM nominal, plan 25–28 CBM loaded
• 40ft standard — 67 CBM nominal, plan 54–58 CBM loaded
• 40ft high cube — 76 CBM nominal, plan 62–68 CBM loaded

The gap is fill factor. Cartons and pallets rarely divide evenly into the footprint, so you lose a strip down one side and a slice at the doors; the last bay is loaded low, because cargo bulging against the doors is how boxes get rejected; pallets eat 145–150 mm of height each and do not stack to the ceiling in whole numbers; dunnage and lashing take up what was CBM on paper.

Work out your own figure: take the carton dimensions, work cases per pallet and pallets per container, and compare with the same volume run through the CBM calculator. The method is in CBM calculation for sea and air freight. If your plan comes out at 95 per cent of nominal CBM, the plan is wrong.

How many pallets fit in a container

This is arithmetic on the floor, not a number to memorise. Take the internal floor as 5,900 × 2,350 mm for a 20ft and 12,030 × 2,350 mm for a 40ft or high cube, and confirm the actual internal width — a few hundred millimetres changes the count.

Euro pallet, 1200 × 800 mm

Laid one way — 1,200 mm along the length, 800 mm across — you get 2,350 ÷ 800 = 2 across and 5,900 ÷ 1,200 = 4 rows: 8 pallets in a 20ft, with 750 mm of width and 1,100 mm of length wasted. Mixing orientations recovers that, because 1,200 + 800 = 2,000 mm fits inside the 2,350 mm width, so a column laid across the box can run beside a column laid along it. A 2,400 mm bay then holds three cross-laid pallets in the 1,200 mm column and two length-laid in the 800 mm column — five per bay. A 20ft takes two bays (4,800 mm) for 10, and the last 1,100 mm at the doors takes one more cross-laid: 11 Euro pallets in a 20ft. A 40ft takes five bays of 2,400 mm exactly — 25 Euro pallets.

ISO / India standard pallet, 1200 × 1000 mm

Straight rows give 2,350 ÷ 1,000 = 2 across and 5,900 ÷ 1,200 = 4 rows, so 8 in a 20ft and 10 × 2 = 20 in a 40ft. Mixing helps less here: 1,200 + 1,000 = 2,200 mm leaves only 150 mm of slack. A 3,000 mm bay holds three cross-laid plus two length-laid; a 20ft gets one full bay plus a part bay of four — 9 pallets, occasionally 10 — and a 40ft gives 20, occasionally 21. Treat the higher counts as best case, not as a plan.

Double stacking

Stacking doubles those counts and is purely a height question. A standard box gives 2,390 mm of internal height, so each tier — pallet plus load — must come in under about 1,190 mm; a high cube gives 2,690 mm, so each tier can run to about 1,340 mm. That is why high cubes are the default for double-stacked pallets. The lower cartons also have to carry the upper pallet; if they cannot, use collars or a bar system, or accept single stack.

Tare, payload, max gross and the road limit

Tare is the empty weight of the container. Max gross is the CSC plate rating — container plus everything in it. Payload is max gross minus tare, the most the container’s own structural rating allows inside.

That rating is rarely the binding constraint on an Indian export. What caps the load is the road move — the permissible gross vehicle weight and axle loading of the trailer taking the box to the port or ICD. Those limits come from motor vehicle rules, vary by state and by vehicle and axle configuration, and are revised from time to time, so do not plan against a number found online: ask your transporter for the permissible payload of the specific trailer he is placing. A 20ft rated for 28 tonnes is often limited to well under that on the road, and the discovery usually happens at a weighbridge.

Separately, the SOLAS container weight rules require the shipper to declare a verified gross mass — cargo plus dunnage plus tare — for every packed export container before it is loaded. VGM is established either by weighing the packed box on a calibrated weighbridge, or by weighing cargo and packing and adding the plate tare under an approved calculation method. The approved methods, documentation route and cut-off are set by the administration and by each carrier, so confirm the current requirement with your line. A wrong or late VGM means the box does not load.

Choosing the right box

High cube. Earns its money wherever you run out of volume before weight — textiles, packaging, plastics, furniture, and double-stacked pallets taller than about 1,190 mm per tier. If your cargo weighs out at 25 tonnes in 55 CBM, the extra 9 CBM is worthless and the standard 40ft is cheaper.

Flat rack. Needed when the cargo will not go through a 2.34 × 2.28 m door opening, or must be loaded by crane from above or the side — machinery, transformers, long sections, plant on skids. Loading becomes an engineering job: lashing plan, weight distribution along the bed, out-of-gauge declaration if the cargo overhangs. That sits with project cargo rather than routine ocean freight, and is quoted case by case.

Open top. The middle option: same footprint and door as a standard box, but with a removable tarpaulin roof over bows and a door header that usually swings out, so cargo can drop in from above. Useful for tall single pieces, glass, marble slabs on A-frames.

Reefer. An insulated box with an integral machine, so its internal dimensions and capacity are meaningfully smaller than a dry container of the same size — a 20ft reefer loses close to half a metre of length and 130 mm of height. Load below the red line, never block the T-floor airflow, set temperature and ventilation per the commodity. The machine holds the temperature you loaded at; it does not pull down warm cargo.

ISO tank. For bulk liquids, rated in litres rather than CBM. The convention is to fill above about 80 per cent to control surge while leaving ullage for expansion, so selection follows the product’s density and expansion, not just volume. For hazardous liquids the tank type, last three cargoes, cleaning certificate and the class and UN number govern what can be loaded — routine for chemicals and dyes shippers, and best settled before the booking.

Buying or leasing a container in India

The price is not one number, and anyone quoting a single figure is quoting one grade, in one city, on one day. What drives it:

• Grade and age. New or one-trip is a factory unit that has made a single laden voyage. Cargo-worthy is certified fit for international carriage and will pass survey. Wind and water tight is sound for storage but not certified for shipping. As-is is sold on inspection with known defects. The spread between one-trip and as-is is very wide.
• Size and type. 20ft and 40ft standard are the liquid market; high cubes carry a premium; reefers, flat racks, open tops and tanks are specialist items with far fewer units available.
• Location and availability. A container is only cheap where there is a surplus. Coastal port prices differ from inland depot prices, and the trade imbalance at that depot moves the number month to month.
• Whether it has to move. A box bought at a Mundra depot and one delivered to a site near Ahmedabad are different transactions; haulage, permits and the crane or side-loader are often a material share of the total.

Boxes are sold by shipping lines releasing off-hire units, by leasing companies, by depot and trading firms, and by Indian manufacturers building new units. Leasing — per day or per month, with pick-up and drop-off written into the agreement — usually beats buying for a defined period.

Budget for what sits beyond the box: road transport to site, crane or side-loader for placement, a level plinth, modification work — doors, vents, windows, flooring, insulation, electricals — repainting, and GST on the supply, which should be confirmed for your case. We publish no container prices, and you should distrust anyone who quotes one without naming grade and depot. Get three written quotes stating grade, year, depot, whether inspection is allowed before payment, and what delivery includes.

When a full container stops making sense

The crossover between LCL and FCL usually sits around 13–15 CBM, but it is a cost comparison on your lane, not a fixed threshold. LCL is charged on the greater of weight or measure with a list of destination charges attached; an FCL is one rate for the box however full it is, so as volume climbs the per-CBM cost of the FCL falls until it undercuts LCL. Dense cargo crosses over earlier. The comparison is worked through in LCL vs FCL shipment.

Talk to Scapex

Scapex Global Forwarding is an international freight forwarder and customs broker based in Ahmedabad, working with Gujarat exporters and importers through Mundra, Pipavav and Nhava Sheva. If you want a stuffing plan checked, a box type confirmed against your cargo, or a straight view on whether a shipment should move LCL or FCL, send us the carton dimensions and weights. Get in touch.