Inner vs outer box dimensions: why your sample ‘doesn’t fit’
PackWorks catalogue sizes are inner dimensions in inches; the outer carton is roughly a quarter-inch larger per side on 3-ply (about half an inch on 5-ply), and couriers always measure the closed outer box for volumetric weight.
Updated 11 Sept 2026 · PackWorks By Velun, Karnal
What “8 × 6 × 4” means on PackWorks
It means the usable inside length, width and height in inches after the box is erected. Your product plus packing allowance must fit inside that space. It is not the courier’s tape-measure reading on the outside.
Why the sample felt smaller
Board thickness eats space. Flutes stand up; flaps fold in; a tight product that matched a competitor’s outer size will jam in an inner-spec carton. Round products also need diagonal clearance — a 4-inch jar may need a 5-inch cube once you add a kraft wrap.
- Measure the product at its widest points, including caps and pumps
- Add 0.25 in per side for a snug apparel/book fit
- Add 0.5–1 in per side when you use bubble, paper or an insert
- Never force flaps shut — bowed flaps fail in the sortation belt
Outer size and volumetric billing
Delhivery, Blue Dart and marketplace pickups measure the closed outer carton. Approximate outer = inner + board build-up. Use centimetres and ÷ 5,000 for surface volumetric kilograms. A 5-ply of the same inner size bills slightly more volume than 3-ply because the wall is thicker.
| Inner (in) | Board | Approx. add per side | Use for |
|---|---|---|---|
| 8 × 6 × 4 | 3-ply | ~0.25 in | Most e-commerce shippers |
| 8 × 6 × 4 | 5-ply | ~0.5 in | Heavy / stacked — check volumetric |
| 10 × 10 × 2 mailer | 3-ply | ~0.25 in | Shallow gifts and mithai |
How to verify before bulk
Order a sample box of the candidate size, load the real SKU with your real void fill, close it the way packers will, then measure outer L×W×H for your rate card. If it fails, move one stock size up — do not jump to a huge leftover carton. The size finder ranks unused inner volume so you can compare candidates quickly.