Quick answer

Dior does not run a universal S/M/L system. Sizes are model specific, so a Mini Lady Dior and a Mini Saddle share a name and nothing else. If you are checking a replica against the real bag, ignore the size label and match three numbers: width, height, and depth in centimeters. Reps usually blow the depth and the handle drop long before they get the width wrong.

The size runs worth memorizing

Lady Dior

  • Mini: roughly 17 x 14 x 7 cm (6.7 x 5.5 x 2.8 in)
  • My ABCDior / small: roughly 20.5 x 17 x 8 cm (8.1 x 6.7 x 3.1 in)
  • Medium: roughly 24 x 20 x 11 cm (9.4 x 7.9 x 4.3 in)
  • Large: roughly 32 x 25 x 13 cm (12.6 x 9.8 x 5.1 in)

Medium is the one most people picture when they say "the Lady Dior." The My ABCDior sits surprisingly close to it and gets mistaken for it constantly in listings.

Saddle

  • Mini: roughly 17 x 15 x 5 cm (6.7 x 5.9 x 2.0 in)
  • Regular / medium: roughly 25.5 x 20 x 6.5 cm (10 x 7.9 x 2.6 in)

The curved flap makes the Saddle hard to measure. Go by the flat back panel, not the front curve.

Book Tote

  • Small: roughly 36.5 x 28 x 17.5 cm (14.4 x 11 x 6.9 in)
  • Medium: roughly 42 x 35 x 18.5 cm (16.5 x 13.8 x 7.3 in)
  • Large: roughly 55 x 43 x 19 cm (21.7 x 16.9 x 7.5 in)

30 Montaigne

  • Flap bag: roughly 24 x 17 x 8 cm (9.4 x 6.7 x 3.1 in)

How to measure your own bag

  1. Stuff the bag lightly so it holds shape without stretching.
  2. Measure width across the front panel at the widest point, seam to seam.
  3. Measure height from the base seam to the top edge, not to the tip of the flap.
  4. Measure depth across the gusset where the bag is thickest.
  5. Measure handle drop from the top of the handle down to the top edge of the bag.

Do all five on a flat surface with a soft tape. Fabric tapes flex and give you a reading a half centimeter off, which matters more than you would think at Mini scale.

Where replicas drift

Depth is the first casualty. A fake that reads 24 cm wide is often 9 cm deep instead of 11, and that one number changes how the bag sits against the body. Handle drop is second. The Lady Dior arch should clear a wrist without looking like a shoulder strap. Strap length on the Saddle is third, and it is where the bag either hangs at the hip or rides up under the arm.

Hardware scale is worth a look too. On the Lady Dior, the letter charms should stay proportional to the panel; oversized charms are a tell on smaller sizes. On the Book Tote, check the embroidery density against the stated dimensions, since a Small pattern scaled up to a Large loses crispness.

Checklist before you commit

  • Ask for width, height, and depth in centimeters, not inches.
  • Ask for the handle or strap drop as a separate number.
  • Compare the depth to the spec above. Anything more than 1 cm off is a different bag.
  • Look at a photo of the bag next to a known object, like a sheet of paper or a phone.
  • Confirm which size name the seller is using, and match it to the dimensions, not the word.

One practical note: counterfeit bags can be seized at the US border and importing them carries civil exposure, so treat a size chart as reference material rather than a green light.

Bottom line

Memorize four numbers per model. Width, height, depth, drop. If a seller cannot give you all four in centimeters, you are guessing, and guessing is how people end up with a "Mini" that is really a small medium.