Why box size matters more than you think
Couriers charge on the higher of actual weight and volumetric weight — length × width × height in cm ÷ 5,000. A 600 g phone case in a 30 × 25 × 15 cm box is charged as 2.5 kg. In a snug 25 × 18 × 12 cm box it is charged as 1.5 kg. Choosing the right box is often the easiest saving a small seller can make.
How much padding?
- Not fragile (clothes, books): about 1 cm, or none for soft goods in a mailer bag.
- Some care (cosmetics, electronics accessories): 2–3 cm of bubble wrap or air pillows on every side.
- Fragile (glass, ceramics, devices with screens): at least 5 cm, the item should not touch any wall, and use a box-in-box for very fragile items.
3-ply or 5-ply?
A 3-ply corrugated box (one fluted layer) is fine for light items up to a few kilograms. Use 5-ply (two fluted layers) for heavy, fragile or high-value goods, or anything that will be stacked in a warehouse. Ask your box supplier for the bursting strength (BF) and GSM; higher numbers mean a stronger box.
Packing checklist
- Fill empty space so nothing moves when you shake the box.
- Seal with H-taping: along the middle seam and both edge seams, top and bottom.
- Put the label flat on the largest face, and a copy of the invoice inside.
Questions
How do I choose the right box size?
Measure the product, add the padding you need on every side (twice per dimension), and pick the smallest box at least that size inside. The calculator does this and suggests the nearest standard carton.
What is volumetric weight?
A weight based on size: length × width × height in cm ÷ 5,000 for most couriers. You are charged for the higher of this and the actual weight.
Is 3-ply or 5-ply better?
3-ply is lighter and cheaper for light goods; 5-ply is stronger and better for heavy or fragile items.
Sources
- Bureau of Indian Standards — IS 2771 corrugated fibreboard boxes
- Volumetric weight: India Post and courier practice (divisor 5,000)
Last checked 2026-11-11. Free to use; please check important details before you rely on them.