Your parcel has already been sent, then an additional freight charge arrives. You weighed it before booking, so what went wrong?
Weight is not always the issue. Suitcase wheels and handles, a bulging carton lid, or foam and wrapping added at the last minute can make the parcel you hand over different from the details you entered.
For parcels that require dimensions, the key principle is simple: finish all packaging first, then measure and weigh the complete parcel, not just the product inside.
There is an important distinction for iShipping courier bag bookings: you do not need to measure the bag's thickness yourself. Select the correct courier bag type for the bag you are actually using. We explain both booking methods below.
1 What is underticketing, and who charges the fee?
Underticketing generally means that the freight paid does not cover the parcel actually sent. Dimensions or weight may have been understated, or the packaging option selected may not match the item. NZ Post also calls insufficient payment under-ticketing or short pay, and explains that a freight adjustment and administration fee may follow its checks. NZ Post insufficient payment information
The freight adjustments and under-declaration fees described here are assessed and charged by the courier company. They are not service fees created or added by iShipping. iShipping can help customers check their booking details against the courier’s reassessment.
The following fee rules are effective from 1 July 2026 and apply to bookings made through iShipping using services covered by this fee schedule. Charges may differ by courier, service or direct-booking arrangement. This table is not a universal tariff for all carriers and should not be confused with the public retail charges in the NZ Post link above.
Situation | Charge levied by the courier |
|---|---|
Ordinary under-declaration of dimensions or weight, outside the oversized case below | $9 + GST |
The measured actual volume exceeds 0.125 m³, but the volume entered at booking is 0.125 m³ or less | $30 + GST oversized under-declaration penalty |
Application of these fees to the same shipment | Either the $9 fee or the $30 fee applies, not both; any freight shortfall is payable separately |
For example, a fully packed carton measures 60 × 50 × 45 cm, giving an actual volume of 0.135 m³. If it was booked as 60 × 50 × 40 cm, the entered volume is 0.120 m³. Its actual volume exceeds 0.125 m³ while the declared volume does not, so the $30 + GST rule above applies, plus any freight difference. The $9 + GST fee is not added as well.
This is an illustrative calculation. To calculate volume in cubic metres, multiply length × width × height in centimetres and divide by 1,000,000. An actual volume of exactly 0.125 m³ does not meet the “exceeds” condition above. Other under-declaration, if present, still needs to be handled under the applicable rule.
The $30 rule is not triggered simply by exceeding a particular weight, nor does it mean every accurately declared large parcel attracts this penalty. Whether a large item is accepted, and whether other charges apply, are separate questions.
2 Do not copy printed carton sizes or online suitcase specifications
Dimensions printed on a carton may be internal or nominal sizes rather than the final external measurements. Cardboard thickness, bulging after filling and the way the box closes can all affect its actual size. The numbers printed on the box are not a substitute for measuring it.
The same applies to suitcase dimensions found online, on a product listing or in a manufacturer's specifications. Model differences, measurement conventions, wheels, handles and the shape of your packed suitcase can affect the result. Labels such as “20 inch” or “28 inch” are not shipping dimensions.
Place the fully packed item on a flat surface and measure its maximum outer length, width and height. Imagine a rectangular box just large enough to enclose the whole parcel: every protruding part must fit inside it.
Do not squeeze soft packaging, hold a handle down or flatten a bulge to obtain a smaller measurement that the package cannot maintain. Adding a fixed number of centimetres is not a substitute for measuring the finished parcel either.
3 Eight packaging situations that need extra attention
Suitcases need to include wheels and handles
Retract and secure the telescopic handle first, then include any fixed handles, wheels, side feet and projecting pockets that remain. If you add a box, foam or a protective cover, measure the outside of that finished packaging.
Check whether the chosen service accepts the suitcase and its contents, and whether an outer box is needed. Accurate dimensions alone do not make packaging suitable for carriage.
Bulging cartons need their highest and widest points measured
A box may be square when empty but develop a raised lid, bulging sides or a sagging base when filled. If a box was 30 cm high but its highest point is 34 cm after sealing, do not continue to enter 30 cm.
Measure bulging sides at their widest points as well. If the contents are clearly forcing the carton out of shape, rearrange them or choose a suitable box rather than pulling it tight with tape and using the empty-box measurements.
Add all wrapping and reinforcement before measuring
Measuring a box, printing a label and then adding thick foam, corner protectors, an outer bag or several layers of wrap is an easy sequence mistake. Those materials are part of the parcel.
Pack the contents, fill gaps and secure them, seal the box, finish the external protection, then measure, weigh and book. Secure loose film ends and straps. Stretch wrap can provide additional protection, but it cannot replace a structurally sound box.
Courier bag bookings do not require a thickness measurement
When booking by courier bag type in iShipping, you do not need to measure or enter the bag's thickness. Simply select the correct type for the courier bag you are actually using. Do not select a smaller bag for a larger one, or book a boxed item as an unsuitable bag product.
This does not mean courier bags have unlimited weight allowances or no content or usage restrictions. Follow the selected bag and service requirements, pack the contents properly and close the bag securely. If you choose a custom parcel option that asks for length, width and height instead of a bag product, enter the actual dimensions of the complete package.
Vacuum packed items can expand again
Duvets, pillows and thick clothing may look compact immediately after compression, but an imperfect seal can let them expand while waiting for collection. Do not measure a size that only holds while you are pressing down on the package.
Check that the packaging can maintain the shape it has when handed over, and check it again before collection. If compression is unreliable, consider a suitable outer box for protection and containment, then measure the sealed box.
Tubes and irregular items need end protection included
Poster tubes, rolled materials and items with protruding parts can have end caps, padding or outer protection that is easy to miss. Include all of it when recording the maximum outer distance in each of the three directions. Do not use circumference as width.
For example, a fully packed tube that is 80 cm long and has a maximum outer diameter of 15 cm in both crosswise directions has external dimensions of 80 × 15 × 15 cm. Do not calculate only the space inside it. Confirm that the selected service accepts the shape.
Tying two boxes together is not recommended
It is generally more practical to pack and send them separately, or use a suitable outer box where the service allows. A few turns of film around two boxes may not keep them intact during handling.
If combined packaging is used, first confirm carrier acceptance. The boxes must form one firm, secure unit that cannot come loose or separate during handling. Loose straps or a thin film connection are not enough. Do not enter the dimensions or weight of only one box: declare the maximum outer dimensions and total weight of the complete combined unit.
Recheck after adding products or changing packaging
A last-minute gift, combined order, replacement box or extra protection can make earlier measurements incorrect. When dispatching in bulk, do not assume that identical products always use identical packaging.
Saved packaging, previous orders and Excel templates can reduce typing, but they cannot replace a physical check. For multiple parcels, verify each item's dimensions, weight and matching label.
4 Use a strong box that helps the parcel retain its shape
Damp, damaged or softened cardboard may lose support during handling and stacking. An undersized box can split when overfilled, while a large box without sufficient internal support may collapse under pressure.
Choose a strong carton suited to the contents' size and weight, fill gaps appropriately, secure heavy items that can move, and seal openings and seams. These steps also align with basic carrier packaging guidance. Aramex packaging guide
Do not remove necessary protection just to enter smaller dimensions, or assume more wrapping will repair a split or weakened box. Stable, complete packaging can help reduce both damage and measurement disputes. For further checks, see our guide to packaging mistakes that cause damage or delays.
5 Weigh all packaging as well as the contents
Use the total weight of the goods and every packaging material, including the box, fillers, covers, tape, stretch wrap and anything else travelling with the item. The product's net weight is not the parcel's shipping weight.
Put the scale on a hard, level surface and check it is zeroed. The parcel must not lean against a wall, touch the floor or be supported by your hand. Check units when entering the result: centimetres and millimetres, or kilograms and grams, are not interchangeable. If a service requires rounding, follow its rules rather than rounding down yourself.
A light item can still need accurate dimensions. Some services compare actual weight with volumetric weight for pricing; the applicable rules depend on the service. Read our volumetric weight guide for more detail.
6 Accurate details do not remove every possible surcharge
An underticketing adjustment is different from a charge associated with an item's size, weight or special handling requirements. Accurate declarations reduce problems caused by incorrect information, but they do not make an item within service limits if it is actually outside them.
Do not assume that offering to pay extra guarantees acceptance. NZ Post's sending standards explain that generating a label does not itself mean a parcel meets carriage limits. NZ Post sending standards
For particularly large, heavy, flexible or unusually shaped items, contact iShipping before booking to check an appropriate service.
7 Complete a final check before booking
Have all wrapping and reinforcement been completed?
For parcels requiring dimensions, have you included bulges, wheels, handles and other projections?
Have you measured the item rather than copied carton markings or online suitcase specifications?
Does the courier bag type match the bag being used, and is the packaging category correct for boxed items?
Does the weight include all packaging, and is the box or combined unit structurally secure?
Have any contents or packaging changed since the label was prepared, requiring another check?
For items that may be difficult to measure, keep photos of the finished packaging, length, width and height measurements, and the scale reading, together with the tracking number. If you receive a charge you believe is incorrect, provide these to iShipping to help check the carrier's recorded measurements. Photos support an investigation; they do not guarantee that a charge will be reversed.
Before your next booking, open the iShipping shipping page, review the Package Dimension & Weight Guidelines and select the actual bag type or enter the finished parcel's dimensions and weight. If you are unsure how to pack or measure a suitcase, irregular item or combined package, send the iShipping team a description and packaging photos before booking so we can help you check the next step.
The fee rules above are effective from 1 July 2026. Amounts are in NZD, plus GST, and are charged by the courier company, not as additional iShipping service fees. Applicability and any other charges depend on the selected service’s current conditions and reassessment. Contact iShipping for help checking a charge or measurement you believe is incorrect.