Dimensional weight calculator: compare two parcel sizes

A light parcel can still produce a surprisingly high shipping quote. Before changing the contents, check the packed box size. This calculator compares two packaging options, A and B, for the same shipment. You can change the measurements, compare the results, and save the rule URL and the date you checked it in a CSV file.

It does not fetch carrier prices. Its results are unrounded comparison values under the selected divisor, not confirmed billable weights or shipping charges.

Check the service, not just the carrier name

The DHL Express UK guide divides volume in centimetres by 5,000 and uses the greater of actual and dimensional weight. That formula is the calculator’s default. A DHL-branded service does not necessarily use the same rule.

The US DHL eCommerce guide uses a divisor of 6,000 for centimetres. It also states an exception: US domestic packages with a volume of one cubic foot or less are charged by actual weight. This calculator does not apply that exception automatically. Entering 6,000 as a custom divisor changes the arithmetic; it does not make the result an exception-adjusted billable weight. Both guides were checked on 9 October 2026.

Measure the finished package

              W ↗
          ┌─────────┐
         /         /│
        ┌─────────┐ │
   H ↕  │         │ /
        └─────────┘
            L ↔

• Keep the cushioning and close the box as you would for dispatch. Do not remove necessary protection just to reduce the volume.
• Check the carrier’s method for protruding or bulging packaging. Measuring only a flat panel can miss the widest part.
• Weigh the complete parcel, including the box, cushioning and tape. If option B uses different packaging, check its weight separately.
• The calculator uses centimetres and kilograms. Convert millimetres or inches before entering them.

Compare your two options

Calculated results are displayed to three decimal places; the CSV retains the calculation’s underlying precision. Rounding for display is not the carrier’s billable-weight rounding.

1. Check the official rule for the country and service you will book. Use the default DHL Express formula only when appropriate; enter another divisor only after verifying it.
2. Enter the packed length, width, height and actual weight for A and B. Treat them as alternatives for sending the same contents.
3. Record the service name, official rule URL and date you checked it. These notes make your assumptions traceable; they do not verify the carrier rule for you.
4. Calculate, compare and save the CSV. Save a new record if the package measurements or checked rule change.
5. Get a carrier quote for the option you choose. Check size and weight limits, rounding rules and any applicable surcharges at that stage.

A worked example you can reproduce

This is a fictional example, not a shipment or a packaging test we carried out. Both options weigh 2.5 kg, and the divisor is 5,000.

B’s comparison value is 2.825 kg lower. That is a weight difference, not a saving in money. The carrier may charge within the same price band, or other charges may apply. A smaller box is not the better option if it cannot protect the contents adequately.

Sending more than one box?

A and B are alternatives, so do not add them together. For an actual multi-package shipment, check the service’s exceptions and rounding, then calculate each shipping package separately before adding the results. Comparing only the sum of actual weights against the sum of dimensional weights can give the wrong result when dense and bulky parcels are mixed. This tool compares one box in A with one box in B; it does not automatically total a multi-package shipment.

What still needs a quote

The calculation does not automatically include dimension or weight rounding, service exceptions, fuel or remote-area charges, oversized-package fees, taxes, customs charges or restrictions on the contents. Listing a possible charge does not mean it applies to your shipment. Ask the carrier about unresolved conditions and use the actual quote to decide on cost. Your saved URL and check date give you a starting point for checking the rule again.