Why your courier bills more than the parcel weighs

You weigh the parcel at 500 grams. The invoice charges you for 1.5 kg. Nothing has gone wrong — you are being billed on volumetric weight, and it is one of the most reliably overlooked costs in ecommerce.

Why couriers do this

A delivery van fills up on space long before it hits its weight limit. A truck full of pillows weighs almost nothing and earns almost nothing, so carriers price on the space a parcel occupies as well as its mass — and bill whichever number is higher.

The formula

volumetric weight (kg) = (L x W x H in cm) / divisor

chargeable weight = the HIGHER of actual and volumetric

A 30 × 25 × 10 cm box is 7,500 cm³. At a divisor of 5000 that is 1.5 kg. Put a 500 g item in it and you are billed 1.5 kg — three times the real weight, on every order, forever.

The divisor is not universal

5000 is the most common, but 4000 and 6000 are both in use, and they are not interchangeable:

same 30 x 25 x 10 cm box:

  divisor 4000 -> 1.875 kg
  divisor 5000 -> 1.500 kg
  divisor 6000 -> 1.250 kg

A lower divisor means a higher charge. Check your own rate card rather than assuming, because a 4000 divisor on a bulky catalogue is a materially different cost base from a 6000 one.

What to do about it

1. Measure your actual boxes. Not the product — the packed parcel, including any void fill.
2. Find which SKUs bill on volumetric. Those are the ones paying for air. The rest are fine and need no attention.
3. Attack the largest dimension. The formula is a product of three numbers, so cutting the biggest one moves the result most. Flat-packing to lose height is often the single cheapest win available.
4. Right-size the box. Using one box size for everything is convenient and expensive. A second, smaller size usually pays for itself quickly.

Why it deserves attention

Shipping is charged on every order you send, including the ones that come back as returns or RTO. So an inflated chargeable weight is not just a cost on your successful sales — it is a cost on your failures too, paid twice on anything that travels both ways.

Unlike return rates, which need listing changes and take time to move, this one is fixable this week with a smaller box.

Check a parcel now with the volumetric weight calculator — enter your dimensions and it tells you whether you are billed on actual or volumetric, and by how much. Then feed the real figure into the Meesho price and profit calculator.