The width names only part of the capacity
A Speedy 25 is 25 cm wide, 19 cm high and 15 cm deep. The Keepall 45 is 20 cm wider, 8 cm taller and 5 cm deeper, which changes volume far more than the width difference suggests: treated as boxes, the two bodies run from 7,125 to 24,300 cubic centimetres, a factor of 3.4. A Neverfull MM at 31 × 28 × 14 cm comes to 12,152 cubic centimetres and an OnTheGo MM at 35 × 27 × 15 cm to 14,175, so the 4 cm wider OnTheGo carries about 17% more. Depth diverges least — 12 cm on the CarryAll PM against 20 cm on the Keepall, while width runs 25 to 45 cm. Set depth against width and the ratio falls from 60% on the Speedy 25 to 41% on the CarryAll PM. Place all three dimensions beside the contents you carry; width alone cannot separate a soft everyday body from a structured travel bag.
Handles, straps and opening geometry
A Speedy has short top handles and a zipped opening; a Keepall adds handles and a bandoulière strap; a Neverfull uses long side straps and an open top. Ask for the clear handle drop, because total handle length includes the curve and the attachment points. Louis Vuitton prints no drop figure for the Neverfull PM, MM or GM, only the note that the handle is double, so the numbers in circulation are third-party measurements of real bags: about 16.5 cm on the PM, about 21 cm on the MM and about 22.9 cm on the GM, with an auction record listing 20 cm on a braided Damier Azur MM. A centimetre of disagreement between two professional measurements is the practical precision limit. Set those drops against the hand-carried Speedy 25, whose short top handles sit close to the body, and the two canvases stop looking interchangeable: same material, different carry.
Where the Neverfull ladder sits in the canvas family
The Neverfull is the one canvas model sold in four current tiers, and the letters are tier names rather than measurements: BB 24 × 14 × 9 cm, PM 29 × 21 × 12 cm, MM 31 × 28 × 14 cm and GM 39 × 32 × 19 cm, figures taken along the base. The GM works out at 23,712 cubic centimetres, within 2.5% of the Keepall 45 at 24,300, so the largest tote and the smallest travel duffle hold a similar box of contents and are separated by the closure and the strap rather than volume. Width needs a stated measurement point here: Louis Vuitton's US Monogram page prints 18.5 in, about 47 cm, for the MM because it measures across the open mouth, while the Damier Ebene and Singapore pages print 31 cm along the base. One resale listing carries both figures for a single Monogram MM, and a chart giving the MM 47 cm and the GM 39 cm has mixed the two.
Canvas is a construction, not a one-size stability promise
Monogram and Damier canvases are coated materials built for a structured or semi-structured body, but the leather trim and bag construction decide how the shape behaves. A rolled leather handle, a reinforced base and a zipper change the way the bag stands when full. The visual pattern does not reveal whether the base is reinforced or how the side panels fold. Inspect the base, trim and interior from several angles. A catalogue image that only shows the patterned front can hide a soft or unstructured side that changes capacity under weight.
Compare a daily bag with a travel body
Speedy 25 is compact enough for a phone, wallet, keys and a compact; Speedy Soft 30 adds room for a folded scarf or small pouch. CarryAll PM and Neverfull MM move toward everyday tote duty. Keepall 45 is visibly a travel or weekend shape, with depth and height intended for clothing or bulky soft items. Do not select a Keepall because its 45 cm width resembles a large tote: the role, handles and opening are different. The model name describes the construction, and the dimensions confirm it.
The source-backed measurement request
Send the model reference, width across the base, height to the top edge, depth at the widest point, handle drop and strap drop if present. For a zipped bag, include opening length; for an open tote, include the widest and narrowest top widths. Add photographs of the front, base and interior. This makes a canvas bag query specific enough to compare with the published models in the table, rather than letting a familiar pattern stand in for all six shapes.