Forklift pockets (also called fork sleeves or handling openings) are reinforced openings in the bottom side rails of shipping containers that allow forklift tines to enter for lifting and transport. These dimensions are internationally standardized to ensure compatibility with forklifts worldwide.
Standard Dimensions for 20-Foot Containers
20-foot containers are typically equipped with forklift pockets as standard.
Dimension Standard Size Notes
Pocket Width ~350 mm (~14 inches) Some sources cite 355 mm
Pocket Height ~115–120 mm (~4.5 inches)
Center-to-Center Spacing ~2,050 mm (~69 inches) One source cites 1,720 mm (67.7 inches)
ISO Standard Specifications (IICL Technical Bulletin)
According to IICL Technical Bulletin TB 017, the ISO-standard minimum dimensions for forklift pocket openings are as follows:
Pocket Type Minimum Width Minimum Height
"Loaded" Pockets 345 mm (13-5/8 in) 105 mm (4-1/8 in)
"Empty" Pockets 295 mm (11-5/8 in) 92 mm (3-5/8 in)
These dimensions are defined under ISO standards including ISO 1496 (technical requirements and dimensions for containers) and ISO 668 (standard dimensions of ISO containers).
Forklift Requirements for Container Handling
Fork Thickness: Standard forklifts from 8–32 tonne capacity are suitable for ISO fork pockets (115 × 355 mm). Specialist "thin line" forks (110 mm thick) are available for 36–40 tonne vehicles.
Fork Spread: For 20-foot containers, forklift pockets are 69 inches from the inside of one pocket to the inside of the other. The forklift must be able to spread its forks that far apart.
Fork Length: If the forklift cannot spread its forks wide enough, forks (or extensions) must be at least 8 feet long to pick up the container from underneath.
40-Foot Containers
40-foot containers do not typically have forklift pockets. The reasons are:
The center of gravity becomes problematic when lifting such a long container with a forklift
The pockets would be too close together, making balance difficult
Instead, 40-foot containers are usually moved using container chassis, reach stackers, gantry cranes, or toplifters. Some used 40-foot containers may also lack pockets.
Offshore Container Specifications
Offshore containers have specific guidelines:
Minimum opening size: 200 mm × 90 mm
Spacing: Minimum distance between opening centers is 900 mm; maximum is 2,050 mm
Summary
Standard 20-foot ISO container forklift pockets measure approximately 350 mm wide × 115–120 mm high, with 2,050 mm center-to-center spacing. ISO minimums are 345 mm × 105 mm for loaded pockets and 295 mm × 92 mm for empty pockets. Forty-foot containers typically lack forklift pockets and require alternative handling equipment. For safe container handling, always verify pocket dimensions against your forklift's fork specifications, including thickness, spread capacity, and length.
For precise specifications, refer to ISO 1496, ISO 668, or IICL inspection guidelines.