Shipping Container Dimensions & Capacity 20' and 40' GP, 40' and 45' HC, reefer, open top and flat rack
Inside size, door opening, volume and weight limits for ten container types. Every reference value comes from a published carrier or lessor specification page, and each type shows the range between sources, because real boxes differ by owner, maker and age.
Metric figures are as published. Feet and inches, cubic feet and pounds are converted by this page (1 in = 25.4 mm, 1 lb = 0.45359237 kg), inches rounded to the nearest ⅛.
All ten types at a glance
Shipping container inside dimensions, door openings, volume and weights with their sources
Max payload = max gross − tare. The figures on the CSC safety-approval plate and the doors of the container you receive are the ones that count: a 40' GP can be rated for 30,480 or 32,500 kg gross, and reefer tare depends on the machinery fitted. Road and rail weight limits in your country may be lower than the container's own payload.
A Specifications by type
Each card gives the reference values, the same values in imperial units and the lowest and highest figure among the published sources compared. Open "Compare all sources" to see every source side by side. "Use this container in the CBM calculator" opens the CBM calculator with that container added to its container estimate.
Reefer inside dimensions are smaller than a dry box of the same length because of the insulated walls, the T-floor and the refrigeration unit. Do not load above the red load line: air must circulate over the cargo. CMA CGM gives the volume usable under the load line separately.
Reefer inside dimensions are smaller than a dry box of the same length because of the insulated walls, the T-floor and the refrigeration unit. Do not load above the red load line: air must circulate over the cargo. CMA CGM gives the volume usable under the load line separately.
Open tops can be loaded through the roof by crane once the tarpaulin and roof bows are removed, so door size is not the limit for top-loaded cargo. Height above the walls is out-of-gauge cargo and needs a special booking.
Open tops can be loaded through the roof by crane once the tarpaulin and roof bows are removed, so door size is not the limit for top-loaded cargo. Height above the walls is out-of-gauge cargo and needs a special booking.
Flat racks have end walls but no side walls or roof, so cargo can overhang the sides or top as out-of-gauge cargo. "Inside volume" is not a meaningful capacity for an open platform: sources that print one give a figure that does not match their own L × W × H. Plan by deck size, payload and lashing points instead.
Flat racks have end walls but no side walls or roof, so cargo can overhang the sides or top as out-of-gauge cargo. "Inside volume" is not a meaningful capacity for an open platform: sources that print one give a figure that does not match their own L × W × H. Plan by deck size, payload and lashing points instead.
45,000 kg rating. Published "load capacity" 53.2 m³ is larger than L × W × H (50.3 m³). ONE also lists a 40' HC flat rack rated 58,600 kg with 52,500 kg payload.
The inside volume is the empty box. Cartons almost never fill it, so freight planners usually budget 80–90% of the inside volume for carton cargo: about 80–85% for mixed carton sizes and up to about 90% for one carton size loaded by an experienced crew. Warp's CBM guide (opened 2026-10-19), for example, tells shippers to plan for 80–85% utilisation because of packing gaps, pallet overhang and door clearance.
Where the rest goes:
Carton sizes rarely divide the box. Each row, column and layer leaves a strip narrower than one carton.
Clearances. Space to close the doors, a gap under the roof to stack the top layer by hand, and corrugated walls that are narrower at the ribs than the published width.
Dunnage and securing. Airbags, bracing and void fill take volume that is paid for but not filled with goods.
Pallets. A pallet footprint rarely matches the floor, and the pallet itself has height. Palletised loads usually reach a lower percentage than hand-stacked cartons.
Weight. Dense goods hit the payload limit long before the box is full. 25 t of tiles fills only part of a 20' GP.
Reefers. Cargo must stay below the red load line so cold air can circulate, which is why CMA CGM gives a separate "usable under load line" volume.
Worked example: 50 × 40 × 30 cm cartons in a 20' GP
Using the 20' GP reference box (5,898 × 2,350 × 2,390 mm, 33.1 m³). Each carton is 0.06 m³.
Volume only, at 85%: 33.1 × 0.85 ÷ 0.06 = 468 cartons. This is the optimistic figure.
One orientation, stacked in a simple grid: 14 along the length (40 cm side) × 4 across (50 cm side) × 7 high = 392 cartons, only 71% of the inside volume.
The grid leaves a 350 mm strip along one wall. Turning cartons so their 30 cm side runs across it adds 56, for 448 cartons, 81% of the volume.
That is why 80–85% is a fair planning figure for a careful hand load, and why a forwarder's load plan, not a volume division, should decide the carton count on a purchase order.
Flat racks are left out: an open platform has no meaningful inside volume. Open-top volumes assume the tarpaulin is on and the cargo stays below the walls.
C Pallets per container (single tier)
Published pallet counts for standard 20' and 40' boxes, and a floor-plan check that this page calculated from the reference inside dimensions (20' GP 5,898 × 2,350 mm, 40' GP and 40' HC 12,032 × 2,350 mm). The floor-plan figure is a geometric maximum with pallets touching each other and the walls; real loads need a little clearance, so plan on the published figure.
Drawn to scale (1 px = 10 mm). A tenth 1200 × 1000 pallet needs 1,200 mm of length beside the row of five, but only 1,098 mm is left, and two pallets with their 1,200 mm side across would need 2,400 mm of width in a 2,350 mm box.
Decimal slips. A 20' GP holds about 33 m³ inside. Figures such as 3.3 m³ or 330 m³ are typing errors; check any table against L × W × H.
Inside and outside sizes mixed. A 20' box is 6,058 mm long outside but about 5,900 mm inside. Only inside sizes matter for loading.
Different weight ratings. ONE publishes its 40' GP at 30,480 kg max gross (payload 26,840 kg); Textainer and SeaCube rate theirs at 32,500 kg (payload 28,800–28,860 kg). Both are correct for those boxes.
Two different reefer door heights. SeaCube gives the 40' reefer door as 2,569 mm "at sill" and 2,502 mm "cargo access". ONE's 2,502 mm and CMA CGM's and Textainer's 2,569 mm are measuring different things.
Reefer tare depends on the machine. Textainer lists 20' reefer tares from 3,010 to 3,130 kg depending on whether a Thermo King, Carrier or Daikin unit is fitted.
Arithmetic that does not add up. ONE's 40' reefer heading says 34,000 kg, but its tare (4,490 kg) and payload (30,510 kg) add up to 35,000 kg. This page uses CMA CGM's internally consistent reefer figures and lists ONE's in the comparison.
"Capacity" for flat racks. ONE prints 28.4 m³ and 53.2 m³ for 20' and 40' flat racks, more than their own L × W × H (27.0 and 50.3 m³). An open platform has no fixed volume.
Representative, not guaranteed. Every source here says its figures are typical or non-contractual. Ask the carrier for the equipment you are booking when a few centimetres matter.
E Sources and method
Every page below was opened on 2026-10-19. The figures were read from the page itself (a fetch of the page, then a plain-text extraction of the same HTML or PDF, compared line by line), not from search snippets or memory. Each type uses one carrier or lessor as its reference source; CMA CGM is used for reefers because its weights add up.
Ocean Network Express (ONE), container specificationsCarrier https://www.one-line.com/en/standard-page/dry-containers Used for: 20' GP, 40' GP, 40' HC, 45' HC, 20' RF, 40' RF, 20' OT, 40' OT, 20' FR, 40' FR. Opened 2026-10-19. Dry, reefer, flat rack and open top tables on one page. "For reference only. Individual containers may have different specifications."
SeaCube Containers, product specificationsLessor https://seacubecontainers.com/product_specs/ Used for: 20' GP, 40' GP, 40' HC, 20' RF, 40' RF. Opened 2026-10-19. "Specifications are approximate and are subject to change." Imperial weights on these pages do not all match the kg values; only kg are used here.
Textainer, Refrigerated specificationsLessor https://www.textainer.com/equipment/refrigerated Used for: 20' RF, 40' RF. Opened 2026-10-19. "Typical" specifications. Tare and payload depend on the refrigeration machinery fitted.
Hapag-Lloyd container pages (hapag-lloyd.com, cargo fleet) and its archived container specification PDF: HTTP 403 for automated requests, so no Hapag-Lloyd figure appears here.
MSC dry cargo and reefer pages (msc.com) and ZIM container pages (zim.com): HTTP 403.
Maersk: the public FAQ lists the types Maersk carries (20' and 40' dry, 40' and 45' high cube, 40' high cube reefer, open tops, flats) but no dimensions; the equipment flyer PDF returned HTTP 403.
The calculator's default 20' GP, 40' GP and 40' HQ figures are representative values (5,898/12,032 × 2,352 × 2,393/2,698 mm) with DSV's payloads. They sit inside the ranges above. When you open the calculator from this page, the container you chose uses the reference values shown here.
F Cite or reuse
Free to link, print and copy for teaching, trade guides and internal training. Please link back to this page and keep the source references with the numbers.
Toolwoven. "Shipping Container Dimensions & Capacity." CBM Calculator reference, data checked 19 October 2026. https://livnaro.cc/container-dimensions
Spotted a different published figure? The comparison tables show exactly which source each number came from, so it can be checked and added.