Package Postage by Weight & Zone Calculator
Estimate the cost of mailing a parcel from its weight and delivery zone using a base rate plus a per-unit and per-zone charge.
How it works
Billable weight = round up(weight) · Cost = base + per-kg·(billable − 1) + zone fee·(zone − 1)
Carriers price a parcel on two axes: how heavy it is and how far it goes. Weight is billed in whole units rounded up, with the first unit folded into a base rate, and each extra unit adding the per-kg charge. Distance is banded into zones — the farther the destination, the higher the zone and the bigger the surcharge on top of the weight cost. Plug in your carrier’s numbers to compare a parcel across weights and zones.
Worked example
A 2 kg parcel to zone 4 with a $6 base, $2.50/kg, and a $1.20 per-zone fee bills as 2 kg: $6 + $2.50·(2−1) = $8.50 for weight, plus $1.20·(4−1) = $3.60 for zones, totalling $12.10.
Frequently asked questions
Why is my weight rounded up?
Postage is charged in whole weight steps, so a parcel just over a kilogram is billed as the next full kilogram. That is why a 1.1 kg and a 1.9 kg box often cost the same to send.
What is a shipping zone?
A zone is a distance band from the origin to the destination. Zone 1 is local and each higher zone is farther away, which is why the same box costs more the farther it travels. Carriers publish a zone chart by postcode.
Does this include dimensional weight?
No — this estimate is by actual weight and zone. Large, light parcels may be billed on dimensional (volumetric) weight instead, whichever is greater, so check your carrier’s rule for bulky boxes.
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This calculator is for educational purposes. Double-check important results before acting on them.