Get the dimensions and weight right before you book — this is the single biggest cause of surprise charges after a parcel is collected.
Every courier prices a parcel on two numbers: how heavy it is and how much space it occupies. You are charged on whichever of those two is greater. If you enter figures that are smaller than the parcel that actually arrives at the depot, the carrier re-measures it on an automated scanner and issues an adjustment — and adjustments are almost always more expensive than booking the correct size in the first place.
The fix is simple: pack the parcel first, then measure and weigh the finished box. Measuring the item rather than the sealed box is the mistake that catches most first-time senders, because padding, tape and box walls can easily add 5–10 cm to each dimension.
Work on a flat surface with the parcel fully packed and taped shut.
Never measure the item on its own. Cushioning, void fill and the cardboard itself all add volume, and the carrier scans the sealed box — so that is what you must measure.
Lay the parcel down and measure its longest edge in centimetres. This is the length. Round every measurement up to the nearest whole centimetre — never down.
Width is the shorter horizontal edge; height is the distance from the surface to the top of the box. Measure at the widest point, including any bulge in the sides.
Handles, wheels, protruding feet, overhanging tape or a lid that does not sit flush all count toward the measurement. Scanners measure the smallest cuboid the parcel fits inside.
Use bathroom scales for anything over 3 kg and kitchen scales below that. For bathroom scales, weigh yourself, then weigh yourself holding the parcel, and subtract. Round up to the nearest 0.5 kg.
Multiply length × width × height in centimetres, then divide by 5000. That gives volumetric weight in kilograms. Compare it with the actual weight — the larger figure is your chargeable weight.
Actual weight is what the scales say. Volumetric weight — also called dimensional or DIM weight — represents the space the parcel occupies in a van or aircraft hold. A courier that filled its vehicles with large, light boxes would run out of space long before it ran out of weight capacity, so carriers charge for volume when volume is the limiting factor.
The standard formula used by DHL, UPS and FedEx is length × width × height in centimetres divided by 5000. Some express and air services use a divisor of 4000 instead, which makes them more sensitive to bulk. GLS and DPD may apply different divisors again. When you request a quote through Cargosender, each carrier's own formula is applied to your dimensions automatically, so the prices you compare are already like for like.
The practical consequence: a 60 × 40 × 40 cm box weighing 4 kg has a volumetric weight of 19.2 kg and will be charged as a 19.2 kg parcel. Shrinking that box to 50 × 35 × 30 cm drops the volumetric weight to 10.5 kg — the same contents, roughly half the chargeable weight.
How the same contents can be charged very differently.
| Parcel | Volumetric | Actual | Charged as |
|---|---|---|---|
| Books, 30 × 20 × 20 cm, 5 kg | 2.4 kg | 5 kg | 5 kg — dense, actual weight wins |
| Winter coat, 50 × 40 × 30 cm, 2 kg | 12 kg | 2 kg | 12 kg — bulk is what you pay for |
| Laptop, 40 × 30 × 10 cm, 3 kg | 2.4 kg | 3 kg | 3 kg — actual weight wins |
| Duvet, 60 × 50 × 40 cm, 3.5 kg | 24 kg | 3.5 kg | 24 kg — compress it before packing |
| Tiles, 40 × 30 × 20 cm, 22 kg | 4.8 kg | 22 kg | 22 kg — dense, actual weight wins |
Measuring the item instead of the packed box — padding and cardboard add real centimetres that the carrier will scan.
Rounding down. A 30.4 cm side is 31 cm as far as the carrier is concerned. Always round up.
Forgetting a protruding handle, wheel or lid. The scanner measures the box that your parcel would fit inside, not the parcel's average size.
Guessing the weight. An estimate that is 2 kg light on a 10 kg parcel is a 20% error and will be corrected at the depot.
Using an old box with bulging or crushed sides — bulge counts toward the measured width.
Booking one price for several parcels. Every parcel is measured and priced individually, even when they travel together.
Choose the smallest box the contents safely fit in. Every centimetre removed from all three dimensions cuts volumetric weight sharply.
Cut down a box that is too tall rather than filling the empty space with padding — score the corners, fold the walls in and re-tape.
Use vacuum or compression bags for bedding, coats and soft goods before boxing them.
Send soft, unbreakable items in a padded poly mailer rather than a box — no rigid walls means far less volume.
Consolidate several small parcels into one well-packed box where the contents allow it; one larger parcel usually beats three small ones.
Weigh and measure before you request quotes, not after — changing the figures later changes the price.
Always the finished, sealed box. Carriers scan the outer parcel on an automated conveyor, so packaging, padding and tape all count. Measuring the bare item is the most common reason people are billed more than their quote.
The carrier re-measures the parcel at its sorting hub and raises an adjustment for the difference. You are charged the corrected rate, and adjustments are typically more expensive than having booked the right size initially. Accurate figures at the booking stage are always cheaper.
Use length × width × height in cm ÷ 5000 as your working estimate — that is the standard for DHL, UPS and FedEx. Some express and air services use ÷ 4000, and GLS and DPD may differ again. Cargosender applies each carrier's correct formula when generating your quote, so you do not have to calculate it per carrier yourself.
No. Kitchen scales work for anything under about 3 kg. Above that, stand on bathroom scales holding the parcel and subtract your own weight. Round the result up to the nearest half kilogram to leave a small margin.
Yes. Carriers price the smallest rectangular box your parcel would fit inside, so irregular shapes — a bicycle, a rolled rug, a lamp — are charged on their outer bounding dimensions, not their true volume. Boxing irregular items tightly is worth the effort.
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