A shoe last is a 3-dimensional wooden or plastic mold upon which a shoe is constructed.
The last used during shoe assembly can affect the overall fit of a shoe, and all lasts include the following dimensions:
- Heel width
- Instep height
- Forefoot width
- Toe box depth
The vast majority of shoe fit issues can be resolved by changing either the size, width, (or both), and the last upon which a shoe is built could also affect fit.