TL;DR: This guide breaks down shipping container dimensions so you can pick the right box for storage or transport. You’ll learn typical shipping container sizes, how many square feet inside a shipping container, and when to choose high cube shipping for extra storage space.
- Standard shipping: Core 20-foot and 40-foot options with typical shipping container width and exterior dimensions.
- High cube shipping: Extra foot of height; compare a 40-foot high cube to standard units.
- Interior area: Quick math for sq ft and usable volume to plan layouts and payloads.
- Weights & capacity: Understand tare, payload, and gross weight to stay compliant.
- Use cases: Match size of shipping container to on-site storage, modular builds, and logistics needs.
If you’re planning a build-out, estimating storage space, or comparing transport options, understanding shipping container dimensions is step one. While the industry revolves around a few workhorse sizes, there are meaningful differences in height, door openings, and specialized variants that affect capacity, usability, and cost. Below is a practical guide to the size of shipping container options, typical shipping container measurements, and how to work out how many square feet inside a shipping container for your project.
Contents
The universal baseline: exterior dimensions
Standard ISO exterior sizes (L × W × H) were created so containers interlock seamlessly across ships, trains, and trucks—this uniformity is what makes standard shipping so efficient.
- 20 ft Standard (20GP): 20′ × 8′ × 8’6″
- 40 ft Standard (40GP): 40′ × 8′ × 8’6″
- 40-foot High Cube (40HC): 40′ × 8′ × 9’6″
Note the constant shipping container width: 8 feet outside for ISO boxes. The most visible variation is height—high cube shipping adds an extra foot (9’6″ external height), which changes interior volume dramatically without changing footprint.
Interior measurements and usable space
Because of wall thickness and door frames, internal measurements are slightly smaller than exterior specs. Figures vary by manufacturer, but the ranges below are common:
20-foot Standard (typical interior)
- Length: ~19’4″
- Width: ~7’8″
- Height: ~7’10”
Floor area (sq ft):
To find how many square feet inside a shipping container, multiply interior length × width.
19.3 ft × 7.7 ft ≈ 149 sq ft (floor area).
Volume is roughly 1,160–1,170 cu ft.
40-foot Standard (typical interior)
- Length: ~39’5″
- Width: ~7’8″
- Height: ~7’10”
Floor area (sq ft):
39.4 ft × 7.7 ft ≈ 304 sq ft.
Volume is ~2,350–2,390 cu ft.
40-foot High Cube (typical interior)
- Length: ~39’5″
- Width: ~7’8″
- Height: ~8’10”
Floor area (sq ft):
Same footprint as 40GP ≈ 304 sq ft, but with ~1 ft more headroom.
Volume increases to ~2,690–2,700+ cu ft.
Quick tip: When comparing shipping container sizes, footprint (sq ft) guides layouts and racking; interior height drives stacking, mezzanines, and HVAC plenum choices.
Doors, weights, and rating terms
- Door openings: Standard double doors are ~7’8″ wide and ~7’5″–7’8″ high. High cubes often add a bit of door height. Side-opening or full-side access variants trade some wall structure for wider door openings, which can improve pallet handling and reduce labor time.
- Gross weight: ISO containers carry a maximum gross weight (container + payload). Typical marine ratings:
- 20GP MGW ≈ 67,200 lb; tare ~4,800–5,200 lb; payload ~62,000 lb
- 40GP/40HC MGW ≈ 67,200 lb; tare ~8,000–8,800 lb; payload ~58,000–59,000 lb
Always check the CSC plate for the exact rating on your unit.
The core lineup: 20-foot and 40-foot
Most projects come down to 20-foot and 40-foot decisions:
- 20GP: Nimble on tight sites, easier to reposition, fast to level. Ideal when 150 sq ft covers your need or when access and crane costs matter.
- 40GP: Doubles length and storage space without doubling logistics costs—great for warehousing overflow and longer materials.
- 40-foot high cube: Same footprint as 40GP with extra height for racking, ductwork, or tall equipment—often the best blend of capacity and cost for conversions.
Common variations and when to choose them
Beyond standard boxes, “specials” tweak shipping container measurements to fit specific operations:
- High Cube Shipping (20HC/40HC/45HC)
- Best for: Tall racking, stacked totes, equipment with overhead clearance needs, and comfort in habitable conversions.
- Why choose: Extra foot of internal height with minor added cost.
- Open Top
- Best for: Over-height machinery, awkward lifts with cranes, or materials loaded from above.
- Specs: Removable tarpaulin in place of a fixed roof; internal height similar to standard with top access.
- Flat Rack
- Best for: Out-of-gauge (OOG) loads like pipes, tanks, and tracked vehicles.
- Specs: Deck with end walls only (some collapsible). Not about sq ft so much as length and lashing points.
- Side-Open / Full-Side Access
- Best for: Rapid picking, events, mobile retail, and wide-format loads.
- Specs: Hinged side panels create large door openings along the length.
- Double Door (“Tunnel”)
- Best for: Drive-through loading, FIFO stock rotation, and dividing the interior into two zones.
- Specs: Doors at both ends; interior storage space is unchanged.
- Refrigerated (Reefer) and Insulated
- Best for: Temperature-controlled staging and cold chain.
- Specs: Slightly reduced interior due to insulation and refrigeration plant; check internal shipping container width and height if racking.
- Extended lengths (45HC, 48′, 53′)
- Best for: Additional cubic capacity in domestic intermodal.
- Specs: 45HC is still ISO-friendly; 48’ and 53’ are common in North American domestic moves (wider bodies up to 8’6″ for 53′ domestic).
Quick reference: typical interior footprints (floor only)
- 10′ Standard: ~7.7′ × ~9.3′ ≈ 72 sq ft
- 20′ Standard: ~7.7′ × ~19.3′ ≈ 149 sq ft
- 40′ Standard: ~7.7′ × ~39.4′ ≈ 304 sq ft
- 40′ High Cube: ≈ 304 sq ft (more volume, same floor area)
- 45′ High Cube: ~7.7′ × ~44.4′ ≈ 342 sq ft (check exact make/model)
Remember: Floor sq ft helps with layout; interior height determines stackability and perceived spaciousness for conversions.
How to choose the right size for your plan
- Static storage solution: Start with floor sq ft you need today, then add 15–25% headroom for growth or seasonal peaks.
- Workshops & offices: Prioritize headroom (high cube) for comfort, overhead lighting, and duct runs.
- Event & retail: Side access or double door reduces dwell time and improves merchandising.
- Industrial freight: Match cargo length and weight to a rated size; confirm gross weight and lashing requirements.
Measuring and planning tips
- Verify interior before cutting: For conversions, field-measure your specific unit—actual shipping container dimensions can vary by a couple of inches.
- Account for finishes: Insulation, framing, and drywall can shave 3–6 inches from shipping container width and height inside.
- Door clearances: If your load is tall, confirm door header height—not just interior height.
- Stacking strategy: High cubes on the bottom row can standardize internal ceiling lines if mixing types.
- Permits & codes: Even though ISO sizes are standard, local rules for foundations, egress, and occupancy vary.
Example: calculating square footage for layouts
If you’re planning shelving down both sides in a 40GP:
- Interior width ~7.7′ minus two 18″ shelves (3′) leaves ~4.7′ aisle.
- Interior length ~39.4′.
- Aisle sq ft ≈ 39.4 × 4.7 ≈ 185 sq ft, plus shelf face area for picking.
- Consider a 40-foot high cube if you want a catwalk or mezzanine.
Putting it all together
- Shipping container dimensions are standardized outside for global logistics, but inside measurements vary slightly by build.
- The standard shipping container width is 8′ external across ISO types.
- Shipping container sizes most people choose are 20-foot and 40-foot; stepping up to a 40-foot high cube increases vertical capacity without changing your site footprint.
- To answer “how many square feet inside a shipping container,” use interior length × width in feet to get sq ft, then adjust for any planned interior finishes.
- Match your plan—storage, transport, or conversion—to the right variant: standard, high cube, open top, double door, side-open, reefer, or flat rack.
With a solid grasp of shipping container measurements, you can select the right box, optimize layouts, and budget accurately—whether you’re staging inventory, building a pop-up, or designing a modular workspace.