Duck CheckedGeometry tool ยท Reviewed July 30, 2026
Will these packing cubes fit this bag?
A cube can have fewer liters on paper and still fit badly. Measure the rectangular space you can actually use, then test one cube size without letting the calculator rotate it magically.
Rectangular fit check
Measure the space inside the bag
This tests one cube size in six square orientations. It does not pretend a soft bag is a perfect box.
Your result
Measure both boxes
Use the space inside the bag and the cube after it is filled. Soft sides and awkward corners still need a real packing test.
What the answer means
A conservative grid, not packing Tetris
The calculator checks all six ways to turn one rectangular cube and counts complete rows, columns, and layers. It never slices a cube, bends the bag, or fills leftover strips with a second cube size.
That makes the answer easy to audit. It also means a flexible bag may hold more in real life, while wheel wells, tapered walls, or an overfilled cube may make it hold less.