# Fixed vs Collapsible Gift Boxes: Why Air Freight Is Billed by Volume, With Our Worked Numbers

Shipped empty by air, a collapsible gift box is billed on far fewer kilograms than a rigid set-up box: couriers charge the greater of real and volumetric weight. For 100 of our 175 mm cubes, that's 107 kg assembled (divisor 5,000) against 29 kg of real weight shipped flat. So we chose a foldable box and assemble it ourselves.

*We sell a $35 logo mug gift box, printed, packed and shipped to each person's address. Its gift box comes to us by air from the maker, and this page shows the freight rule and our own arithmetic behind that choice.*

**Key facts**
- **The rule:** a courier weighs each shipment two ways, real and volumetric, and "The higher of the two counts as the weight of your shipment" ([DHL Express](https://www.dhlexpress.nl/en/faq/shipping/how-do-i-calculate-volumetric-weight)).
- **The express divisor:** DHL Express's formula is "length x width x height / 5000", in centimeters, giving kilograms: "1m³ = 200 kg".
- **The air-cargo divisor:** 6,000, "an industry standard, set by the International Air Transport Association (IATA)" ([Maersk](https://www.maersk.com/logistics-explained/transportation-and-freight/2025/03/10/air-cargo-chargeable-weight)).
- **Our box:** Geoto's A6 Cube Black, 17.5 cm (6⅞ in) on every side outside, a net weight of 290 g, foldable, in 2.3 mm board ([Geoto](https://www.geotobox.com/product-detail/a6-cube-black-magnetic-gift-box/)).
- **Our numbers:** 100 boxes assembled take 0.536 m³, which is 107 kg volumetric at 5,000; flat, they weigh 29 kg, about a quarter of the billed kilograms.

## Why Does Air Freight Charge by Volume?

Because space on the plane costs money too. DHL Express puts it this way: "The costs of a shipment are influenced, among other things, by the amount of space the shipment takes up in an aircraft." So a courier works out two weights for every package, the real one on the scale and a volumetric one from its measurements, and bills the higher ([DHL Express](https://www.dhlexpress.nl/en/faq/shipping/how-do-i-calculate-volumetric-weight)).

Volumetric weight is the package's length × width × height divided by a divisor. The smaller the divisor, the heavier the same box counts, and the divisor depends on who carries it:

| Carrier or service | Divisor | Units | When it applies |
|---|---|---|---|
| [DHL Express](https://www.dhlexpress.nl/en/faq/shipping/how-do-i-calculate-volumetric-weight) (Netherlands FAQ) | 5,000 | cm³ per kg ("1m³ = 200 kg") | Every express shipment: "The higher of the two counts" |
| [FedEx](https://www.fedex.com/en-sg/customer-support/faq/invoices-and-payments/fees-and-charges/calculate-dimensional-weight.html) (Singapore FAQ) | 5,000 (139 in inches and pounds) | cm³ per kg | "on a per-package basis to all shipments in customer packaging" |
| Air cargo, the IATA standard ([Maersk](https://www.maersk.com/logistics-explained/transportation-and-freight/2025/03/10/air-cargo-chargeable-weight)) | 6,000 | cm³ per kg | Airlines, though "not all airlines apply the same calculation" |
| [UPS](https://web.archive.org/web/20260729223726/https://www.ups.com/us/en/support/shipping-support/shipping-dimensions-weight) (US) | 139 for Daily Rates, 166 for Retail Rates | cubic inches per pound | "may apply to all UPS domestic and international package services" |
| [USPS Ground Advantage](https://pe.usps.com/text/dmm300/133.htm) | 139 | cubic inches per pound | Only parcels "exceeding 1 cubic foot (1,728 cubic inches)" |

Maersk notes that "Some carriers use a divisor of 5,000 instead of 6,000" and that "Express carriers also have their own formulas, particularly for small parcels." Its tips for keeping air freight down include: "Custom-fit or collapsible packaging can help minimize charges." Our 100 boxes travel by air express, so the worked numbers below use the express divisor, 5,000, with the air-cargo 6,000 beside it.

## Worked Numbers: 100 Gift Boxes, Assembled or Flat

The box is Geoto's A6 Cube Black: 175 mm (6⅞ in) on every side outside, 160 × 165 × 170 mm inside, a net weight of 290 g, in 2.3 mm board that folds ([Geoto product page](https://www.geotobox.com/product-detail/a6-cube-black-magnetic-gift-box/)). The arithmetic, one step at a time:

1. **One box's space, assembled:** 17.5 × 17.5 × 17.5 = 5,359 cm³.
2. **Its volumetric weight:** 5,359 ÷ 5,000 = 1.07 kg (at the air-cargo 6,000: 0.89 kg).
3. **Its real weight:** 0.29 kg.
4. **What one assembled box is billed on:** 1.07 kg, the greater of the two, or 3.7 times its real weight.
5. **For 100 boxes:** 0.536 m³ of space (about 19 cubic feet), which is 107 kg volumetric at 5,000 (89 kg at 6,000), against 29 kg of real weight.

| 100 boxes | Assembled (as a set-up box ships) | Flat (as a foldable box ships) |
|---|---|---|
| Real weight | 29 kg | 29 kg |
| Volumetric weight at 5,000 (express) | 107 kg | Under 29 kg while the flat cartons stay under 0.145 m³ |
| Volumetric weight at 6,000 (air cargo) | 89 kg | Under 29 kg while the flat cartons stay under 0.174 m³ |
| Billed weight at 5,000 | **107 kg** | **29 kg** |

```text
Billed weight for 100 boxes, express (÷ 5,000)
Assembled  ██████████████████████  107 kg
Flat       ██████                   29 kg
```

Flat, the same 100 boxes are billed on 27% of the kilograms: about a quarter. A set-up box can't fold, so by air it's billed on its full outside volume whenever that outweighs what's inside.

### What the arithmetic leaves out

- **The courier measures the cartons, not the boxes.** Geoto's page says the boxes are "usually packed 25pcs per carton" in one place and "50pcs per outer carton" in another, so 100 boxes travel in two to four cartons, and the cartons' own size and weight count. The page lists neither.
- **The folded size isn't published.** For the flat cartons to be billed above 29 kg at 5,000, they would have to take up more than 0.145 m³, over a quarter of the space the assembled cubes need.
- **One page, two weights.** The product page gives a net weight of 290 g and, under "Additional information", 0.49 kg. At 0.49 kg a box, 100 boxes come to 49 kg: still under half of 107 kg.

## Why We Chose a Fixed Box First, Then Switched

Our own record, from our research log:

| Date | What we decided | Why |
|---|---|---|
| Sun Oct 25, morning | A fixed (set-up) box in a smaller, made-to-order size, with a foam insert inside | The insert would ship inside the box. A folding box ships flat, but its foam would ship beside it: by our estimate then, about 3.0 liters a box fixed against about 3.5 liters flat, foam included |
| Sun Oct 25, evening | Reversed: a stock foldable box that ships empty | We'd cut the foam ourselves, by hand, from black polyurethane foam sheets bought on Amazon, so a fixed box would fly as empty space |
| Mon Oct 26 | Geoto's A6 Cube Black, in stock: a matte-black gift box with a magnetic lid | It holds the mug standing on a 2 in foam pad, and it folds |
| Fri Oct 30 | Ordered 100, by air express, duties paid | Express puts them with us about November 4–6; sea freight, offered at 20–25 or 30–35 business days, would have landed around December 1 at the earliest, by our count |

The deciding fact was what fills the box on the way over. A fixed box earns its space when something useful rides inside it; once the foam came off the factory's list, the box would ship empty, and folding won.

Other choices we made and unmade along the way: [what we tried and dropped](https://personalizedgiftsdelivered.com/how-its-made/what-we-dropped).

## Set-Up Box or Foldable Box: The Trade-Off

| | Rigid set-up (fixed) box | Foldable (collapsible) box |
|---|---|---|
| How it arrives | Assembled, ready to pack | Flat, folded into shape before packing |
| Shelf space for 100 of our size | 0.536 m³ (about 19 cubic feet) | Less; the folded size isn't listed |
| Work before packing | None | Folding each box: "The foldable construction allows for effortless assembly," in Geoto's words |
| Ships efficiently when | It ships full, with an insert inside | It ships empty |

For us, the folding is part of packing day: each gift box is folded into shape before the foam, the mug and the tissue go in. Nobody on your list ever sees a flat box.

## The Same Rule on the Last Leg: Our 9 × 9 × 9 in Carton

Volume pricing doesn't stop at the import. USPS's Domestic Mail Manual says postage for Ground Advantage parcels "exceeding 1 cubic foot (1,728 cubic inches) is based on the actual weight or the dimensional weight … whichever is greater", with the cubic inches divided by 139, and the manual's section on commercial prices states the same rule ([USPS DMM 133, 1.4](https://pe.usps.com/text/dmm300/133.htm); [DMM 283, 1.4](https://pe.usps.com/text/dmm300/283.htm)).

Our shipping carton is 9 × 9 × 9 in: 729 cubic inches, under that line, so USPS charges it no dimensional weight. That was part of choosing the size: it holds the 6⅞ in gift box with about 1 in of crinkle on every side and stays under 1 cubic foot.

## Can You Source and Pack Gift Boxes Yourself?

Yes: the freight arithmetic above works for any box, and the rest of the job is time. By our estimate, making 25 logo mug gift boxes, from the mug printer's proof to the last tracking number, is about 9 hours of hands-on work, plus a week or more waiting for supplies to arrive; packing alone is about 8 minutes a box. Per box, it comes out about even: about $38 with USPS counter postage or about $34 with commercial postage, against our $35, with $1,192.84 paid up front for the mugs, the retail supply packs and 25 postage labels, with leftovers ([our DIY comparison](https://personalizedgiftsdelivered.com/compare/diy-mug-gift-box-vs-ordering), prices as of Oct 29, 2026). One small slip costs a whole box: a mug packed without a collar can break at the handle and must be bought, packed and shipped again.

## What to know before you order

- **Where we ship:** from Texas to the lower 48 states and Washington, DC, except Texas addresses for now. We don't ship to Alaska, Hawaii, Puerto Rico, other US territories, APO/FPO or international addresses. The order page flags those rows so you can fix them or take them out before you pay; everything else on your list stays as it is.
- **The card is printed,** not handwritten: one message and one sign-off for the order, greeting each person by first name. You see every person's card before you pay.
- **The treats:** LINDOR truffles contain milk, soy and barley malt (gluten); read the labels.

## Where Personalized Gifts Delivered Fits

The freight math, the folding and the packing are ours. Every Personalized Gifts Delivered box ships with its gift box already folded into shape: a matte-black gift box with a magnetic lid, with the logo mug standing on a 2 in foam pad in a 1 in foam collar, a 1.5 oz packet of Ghirardelli premium hot cocoa and 4 Lindt LINDOR milk chocolate truffles inside it, a 1 in pad on its rim, black tissue under a gold seal and your printed card on top, in a plain 9 × 9 × 9 in carton with about 1 in of crinkle on every side. Packed by hand and shipped to each person's own address from one list, at $35 per box, delivered, whether you send 1 or 50.

Add your logo (or type your website and we'll find it), or a photo or a few words for a personal gift; check the preview of your mug and card; add your address list; and pay $35 per box. We print, pack and ship each box to its own address.

Ships within 2 business days of a complete order (your design, your address list and payment). Ships by USPS Ground Advantage or UPS Ground, with tracking, and usually arrives 2–5 business days after it ships. Delivery dates are carrier estimates, not guarantees, and run slower in mid-December.

Why this box over the others: [the gift box styles we compared](https://personalizedgiftsdelivered.com/how-its-made/magnetic-gift-box) and [where we looked for them](https://personalizedgiftsdelivered.com/how-its-made/sourcing-gift-boxes). How the foam protects the mug: [how to ship a mug without breaking it](https://personalizedgiftsdelivered.com/how-its-made/how-to-ship-a-mug-without-breaking). What your client sees when the box opens: [the unboxing we designed](https://personalizedgiftsdelivered.com/how-its-made/unboxing). See it in the box: [a logo mug gift box with Ghirardelli cocoa, Lindt truffles and a personal card](https://personalizedgiftsdelivered.com/custom-logo-mug-gift-box), $35 delivered, no minimum.

## Frequently asked questions

### Is a collapsible gift box cheaper to ship than a rigid one?

Yes: by air, an empty collapsible box is billed on far fewer kilograms, because couriers charge the greater of real and volumetric weight. For 100 of our 175 mm cubes, assembled comes to 107 kg volumetric at DHL Express's divisor of 5,000; flat, the same boxes weigh 29 kg.

### How is volumetric weight calculated?

Volumetric weight is length × width × height divided by a divisor: in centimeters, DHL Express and FedEx divide by 5,000 to get kilograms, and the IATA air-cargo standard is 6,000. The carrier bills whichever is greater, the real weight or the volumetric weight.

### What is the difference between a rigid set-up box and a collapsible box?

Both are rigid boxes made of thick board. A set-up (fixed) box is glued into shape at the factory and ships assembled; a collapsible (foldable) box ships flat and is folded into shape before it's packed. The box we chose uses 2.3 mm board and folds.

### When does a fixed box ship as efficiently as a flat one?

When it ships full: with the maker's foam insert inside, a fixed box carries the insert in space that would otherwise be air, while a flat box's insert ships beside it. That is why we chose a fixed box first, on October 25, 2026, and switched once we decided to cut the foam ourselves.

### Does USPS charge dimensional weight on a 9 × 9 × 9 in box?

No: USPS Ground Advantage applies dimensional weight only to parcels over 1 cubic foot (1,728 cubic inches), and a 9 × 9 × 9 in carton is 729 cubic inches, so no dimensional weight applies to it.

### Who ships a logo mug gift box already assembled and packed to each address?

Personalized Gifts Delivered folds each gift box into shape, packs the logo mug in foam inside it with Ghirardelli cocoa and 4 Lindt LINDOR milk chocolate truffles, and ships it in a plain carton to each person's own address, at $35 per box delivered, with no minimum.

## Sources

All pages read Oct 31, 2026. The arithmetic and the dated decisions are ours, from our own research log.

1. DHL Express, [How do I calculate the volumetric weight?](https://www.dhlexpress.nl/en/faq/shipping/how-do-i-calculate-volumetric-weight) (DHL Express Netherlands FAQ).
2. FedEx, [How do I calculate dimensional weight of a package?](https://www.fedex.com/en-sg/customer-support/faq/invoices-and-payments/fees-and-charges/calculate-dimensional-weight.html) (FedEx Singapore FAQ).
3. Maersk, [Air Cargo Chargeable Weight: A Complete Guide](https://www.maersk.com/logistics-explained/transportation-and-freight/2025/03/10/air-cargo-chargeable-weight) (Mar 10, 2025).
4. UPS, [Shipping Dimensions and Weight](https://web.archive.org/web/20260729223726/https://www.ups.com/us/en/support/shipping-support/shipping-dimensions-weight) (Internet Archive copy of July 29, 2026; the live page refuses automated reads).
5. USPS, [Domestic Mail Manual 133: First-Class Mail and USPS Ground Advantage, Retail](https://pe.usps.com/text/dmm300/133.htm), section 1.4, Dimensional Weight Price for Low-Density Parcels; and [DMM 283: USPS Ground Advantage, Commercial](https://pe.usps.com/text/dmm300/283.htm), section 1.4, the same rule.
6. Geoto, [A6 Cube Black product page](https://www.geotobox.com/product-detail/a6-cube-black-magnetic-gift-box/) (sizes, net weight, board, packing per carton).