Storage boxes are sold by internal volume, which is precise, comparable and almost useless for working out whether your things will fit.
Volume Is Not Capacity
A box rated at seventy quarts holds seventy quarts of water. It does not hold seventy quarts of duvets, books or Christmas decorations, because none of those pack without gaps.
Real capacity depends on what you are storing. Soft goods compress and fill space efficiently. Rigid objects leave voids around them, sometimes wasting a third of the volume.
The Dimensions Matter More
Two boxes of identical volume can be completely different shapes, and shape is what determines whether a specific item fits.
- Check the internal length against the longest thing you are storing
- Check the height against the shelf it will sit on
- Check the footprint against the space available
- Check whether the lid adds height when closed
- Check external dimensions for stacking, internal for contents
Catalogues that state the quart figure on each card, of the kind at olarhike.net, make comparison across a range straightforward, and the dimensions are what answer the question of whether a particular thing fits.
A Rough Conversion
One quart is a little under a litre, so a hundred-quart box is roughly ninety-five litres.
For anyone used to litres, dividing the quart figure by about one and a tenth gives a usable approximation.
Smaller Boxes Are Frequently Better
The counter-intuitive point. A very large box holds more and becomes too heavy to move once it is full.
A hundred-quart box packed with books is beyond what most people can lift safely. Two smaller boxes are easier to carry, easier to stack and easier to search.
Matching box size to contents density, rather than buying the largest available, is the practical approach: small boxes for heavy things, large boxes for light bulky ones.
What Fits, Roughly
A moderate box in the fifty-quart region holds a duvet and covers, or a season of clothing for one person, or a mixed box of decorations.
Larger boxes suit bedding, soft furnishings and anything bulky and light. Smaller ones suit books, tools, paperwork and anything dense.
Measure the Space First
The dimension that catches people out is height, particularly under a bed, in a loft with sloping eaves, or on a garage shelf.
Measuring the space before ordering, rather than the contents, prevents the most common return in this category.
Buy Matching Sizes
Boxes of one or two sizes stack squarely and use a space efficiently. Assorted boxes waste the gaps between them and cannot be stacked reliably.
This matters more than the individual capacity, since a wall of matching boxes holds considerably more than the same volume in mismatched ones.
Fill Weight, Not Volume
The practical limit is what you can carry. Packing to the top with anything dense produces a box that stays where it is.