Volumetric weight calculator
Enter your parcel's size to see the chargeable weight carriers actually bill — with the exact divisor and rounding rule we applied, so you can check the maths against your rate card.
Enter your parcel
Volumetric weight
14.50kg
72,000 cm³ ÷ 5000
Actual weight
3.00kg
as weighed
Billable weight
14.50kg
14.50 kg · 31.97 lb
Your box is billed by volume. It takes up more space than its weight suggests, so the carrier charges 14.50 kg rather than the 3.00 kg on your scale. Shrinking each side by 5 cm would cut the volumetric weight by roughly 33%.
Divisor 5000 (cm³/kg) · Carrier rate & service guides. Source ↗
How to use it
Volumetric weight is a pricing rule, not a physical property. A delivery van fills up with boxes long before it reaches its payload limit, so carriers charge for the space a parcel occupies whenever that space is worth more than its weight. The calculation takes ten seconds; the part worth getting right is which divisor you pair with which unit.
- 1
Measure the packed box
Measure the outside of the box at its longest points, with the tape flat against the carton — including any bulge from what's inside. Carriers measure what they can see, not what you intended to pack.
- 2
Pick your carrier's divisor
International express uses 5,000 (cm/kg) or 139 (in/lb). Air cargo usually uses 6,000. If your rate card names a divisor, use that one.
- 3
Read the billable weight
The calculator compares volumetric against actual weight and highlights the greater of the two. That is the figure your rate is looked up against.
The formula, explained
Every carrier uses the same shape of calculation. Multiply the three outside dimensions to get the volume, divide by a published divisor, and compare the answer against what the parcel weighs on a scale:
volumetric weight = (length × width × height) ÷ divisor
billable weight = max(volumetric weight, actual weight)
The divisor is the carrier's assumed density: how many cubic centimetres it is willing to move per kilogram of billed weight. A 5,000 divisor says “we will carry 5,000 cm³ for every kilo you pay for.” That is why a smaller divisor is worse for you, not better — dividing by 4,000 instead of 5,000 raises the volumetric weight by 25%.
Two details trip people up. The first is unit matching: 5,000 is a cm³/kg figure and 139 is its in³/lb equivalent. Applying 5,000 to inches understates the answer by roughly twelve times, which is how people end up with a quote that bears no relation to the invoice. The second is scope — express couriers apply the comparison to each piece and then sum, so a single oversized carton in an otherwise dense shipment is billed on its own volume.
The rounding change from 18 August 2025
FedEx announced in July 2025, and UPS matched, that each fractional dimension is now rounded up to the next whole inch before the divisor is applied. An 11.1 inch side bills as 12 inches. On a 11.1 × 9.2 × 7.4 in carton that turns 755 in³ into 864 in³ — about 0.8 lb of extra billable weight from measurement rounding alone. This calculator applies the same rule when you work in inches on an express service.
Worked examples
Example 1 — metric, a light bulky box
A 60 × 40 × 30 cm carton of cushions weighing 3 kg, shipped by DHL Express at a 5,000 divisor:
60 × 40 × 30 = 72,000 cm³
72,000 ÷ 5,000 = 14.4 kg volumetric
rounded up to the next half kilo = 14.5 kg
max(14.5, 3) = 14.5 kg billable
You pay for 14.5 kg to move 3 kg of cushions. Nearly five times the scale weight — and no amount of removing items from the box changes it, because the box is the problem.
Example 2 — imperial, with the ceiling rule
A 24 × 18 × 12 in carton weighing 7 lb, shipped by UPS at a 139 divisor:
24 × 18 × 12 = 5,184 in³
5,184 ÷ 139 = 37.3 → 38 lb volumetric (rounded up)
max(38, 7) = 38 lb billable
Had the sides measured 23.2 × 17.5 × 11.4 in, the ceiling rule would still bill them as 24 × 18 × 12 — the same 38 lb. Measuring carefully to the nearest fraction of an inch buys you nothing on express services now; choosing a smaller box does.
Carrier divisor reference
The divisors below are the published figures for standard retail and list-rate services. Negotiated contracts frequently carry a different one — a better divisor is one of the most valuable things to ask for in a rate negotiation, and one of the least requested.
| Carrier / mode | Metric (cm³/kg) | Imperial (in³/lb) | Notes |
|---|---|---|---|
| Express courier — DHL, UPS, FedEx | ÷5,000 | ÷139 | The default for international express parcels. Applied per piece, then summed. |
| Air cargo — IATA general cargo | ÷6,000 | ÷166 | Compares shipment totals, not individual pieces. |
| Economy / regional (parts of Asia) | ÷4,000 | — | A smaller divisor means a HIGHER volumetric weight — economy is not always cheaper. |
| USPS (Priority Mail over 1 cubic foot) | — | ÷166 | Only applies to packages larger than one cubic foot (1,728 in³). |
Reviewed annually and after each carrier's rate announcement. Two changes to note for 2025–2026: the 18 August 2025 dimension-rounding rule at UPS and FedEx, and a raised additional-handling weight minimum (UPS from 26 January 2026, FedEx from 12 January 2026) that hits the same large-but-light parcels this calculator is for.
How to reduce volumetric weight
Once volume is driving your rate, the only lever that matters is the outside of the box. In rough order of impact:
- Right-size the carton. Volume is a product of three numbers, so taking 2.5 cm off each side of a 40 × 30 × 20 cm box cuts the volume by about 20% — not 6%. This is the single biggest lever and it is almost always available.
- Cut the void fill, then cut the box. Air pillows are free to buy and expensive to ship. If a third of your carton is padding, you are paying to move a third of a carton of air on every order.
- Stock more box sizes. Most small shippers use two or three sizes and force everything into them. Five well-chosen sizes typically pays for itself within a month at any real volume.
- Watch bulge. An overstuffed carton measures larger than its flat dimensions, and carriers measure the bulge. A box that needs to be forced shut is already costing you money.
- Split, don't upsize. Two right-sized cartons often bill less than one oversized one, especially once large-package surcharges enter the picture — check yours with the girth & size checker.
Accuracy
Estimates only. Carriers and customs authorities determine the final figure — confirm with your carrier before you ship.
How we source and maintain this data
Divisors come from each carrier's published rate and service guide, not from aggregator sites. Where a carrier publishes only one unit system — USPS publishes an imperial divisor and no metric one — we show a dash rather than converting, because a converted divisor is not the number the carrier applies.
The result panel names the divisor it used and links to its source every time, so nothing here has to be taken on trust. If your invoice disagrees with this calculator, the likeliest causes are a negotiated divisor, a surcharge that is not a weight charge at all, or a dimension the carrier re-measured on its own equipment.
Review cadence: Divisors and rounding rules are reviewed annually and after each carrier's rate announcement, which typically lands late in the year and takes effect in January. Last reviewed August 2026. This tool is built and maintained by the ParcelTracking team, who run multi-carrier tracking across 3,000+ carriers.
Primary sources
Volumetric weight FAQ
Volumetric weight — also called dimensional or DIM weight — is the weight a carrier assigns to a parcel based on how much space it occupies rather than what it weighs. Vehicles and aircraft run out of room long before they run out of payload, so carriers price by whichever measure is larger. You are billed on the greater of volumetric weight and actual scale weight.
Most international express services — DHL, UPS and FedEx — use 5,000 when you measure in centimetres and kilograms, or 139 when you measure in inches and pounds. IATA general air cargo typically uses 6,000. Some economy and regional services use 4,000, which produces a higher volumetric weight, not a lower one. Your rate card is the authority; if it names a divisor, that divisor wins over any figure on this page.
Yes. Volumetric weight, dimensional weight, DIM weight and cubic weight are four names for the same calculation. Billable weight and chargeable weight are different terms again — those mean the final figure after volumetric and actual weight have been compared.
Because the box is large relative to its contents. A 60 × 40 × 30 cm carton takes up 14.4 kg of space at a 5,000 divisor no matter what is inside it — so a 3 kg order of pillows and a 14 kg order of books in the same box cost the same to ship. Reducing box size, not weight, is what lowers the bill.
Yes. Since 18 August 2025, both round each fractional dimension up to the next whole inch before applying the divisor — an 11.1 inch side is billed as 12 inches. On a box with three fractional sides that alone can add several pounds of billable weight, which is why this calculator applies the same rule when you work in inches on an express service.
Almost, but not quite. Flat-rate and cubic-priced products deliberately ignore it — USPS Priority Mail Flat Rate charges by box, not by weight or volume, and USPS only applies dimensional pricing to packages over one cubic foot. For everything else, assume volumetric weight applies.
Express couriers calculate it per piece and then add the results together, so one oversized carton cannot be averaged out by dense ones. IATA air cargo compares the shipment's total volumetric weight against its total gross weight. Our chargeable weight calculator supports both bases.
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