Capacity vs Dimensions: What's The Difference?

This is the single most misunderstood thing about bags — and it causes unnecessary returns and confused customers.

External dimensions = The space the bag TAKES UP

Measured in: cm or inches (L × W × D)

What it tells you: Will the bag fit inside a suitcase, under a plane seat, or on a shelf?

Example — Large bag:
29 cm (L) × 17 cm (W) × 7 cm (D)

That's the space the bag occupies when closed and empty. It's useful for packing a suitcase or stocking a retail shelf.

Capacity = The space INSIDE the bag for your STUFF

Measured in: Litres (L)

What it tells you: How many bottles, toothbrushes, and razors can you actually pack?

Example — Large bag: 
3.5 L

That's the internal volume available for toiletries and cosmetics. It's always slightly different from the external dimensions because:

• The bag has walls, seams, and zippers that take up space
• The shape isn't a perfect rectangle (corners are rounded)
  
• Pockets or dividers reduce usable volume

Quick comparison

Which one matters to your retail customer

Customer asking:** "Will this fit under the plane seat?"  
Look at external dimensions

Customer asking: "Can I fit my full-size shampoo and conditioner?"  
Look at capacity