Home / Logistics & shipping

Dimensional weight calculator

Paste the shipment’s package list, pick the carrier rule and see whether the load bills on actual or DIM weight, what the freight costs and how much of it each product carries.

Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.

Check
Mode and DIM factor

Changing the mode loads the usual factor. What counts is the factor in your carrier contract.

Packages
See what was read

Separate with semicolons or paste straight from a spreadsheet. Use the outside dimensions of the finished package.

Freight estimate
—Chargeable weight
—

Actual vs. DIM weight by item

Total for each line of the list (quantity × weight of each package).

Tap the chart to see the values.

DIM weight and freight split by item

The split allocates freight by the weight actually billed (actual or DIM), useful for costing each product.

The same load with other DIM factors

Shipment chargeable weight with the usual factor of each mode. The dashed line is the actual weight.

Tap the chart to see the values.

Next step

Take this page’s results to another calculator with the fields already filled in.

The calculation report gathers this page's inputs, results, equations, assumptions and references, with fields for project, engineer and revision. The full report also includes the charts and interpretations, in color. In the print dialog, choose Save as PDF.

Method, assumptions and references

Equations used

Volume = L × W × H × quantity; DIM weight = volume (in³) ÷ divisor (in³/lb) = volume × density factor
Factor from divisor: kg/m³ = 1,000,000 ÷ (cm³/kg) = 27,680 ÷ (in³/lb); lb/ft³ = 1,728 ÷ (in³/lb)
Chargeable per shipment = max(Σ actual, Σ DIM); per package = Σ max(actual, DIM)
Freight = max(chargeable weight × rate, minimum) + declared value × valuation %

Assumptions and limits

  • The factors in the list are common market values; each carrier sets its own in the contract or service guide, and many round dimensions and weights up (for example, to the next inch or pound). Use the contract value.
  • Freight is a linear estimate on chargeable weight. Real rate tables have zones, weight breaks, fuel and residential surcharges, accessorials and, in LTL, NMFC freight classes, which are not modeled here.
  • The split by item allocates total freight in proportion to the weight each item makes the carrier bill (DIM if the shipment pays DIM, actual otherwise).

Standards and technical documents

  • IATA. The Air Cargo Tariff and Rules (TACT Rules): volume weight of 6,000 cm³ per kg
  • UPS and FedEx Service Guides: dimensional weight divisors (139 in³/lb for daily rates)
  • USPS Domestic Mail Manual (DMM) 123: dimensional weight with divisor 166
  • NMFTA. National Motor Freight Classification (NMFC): density-based freight classes
  • ISO 668: Series 1 freight containers — Classification, dimensions and ratings
  • Convenção CMR (Genebra, 1956): contrato de transporte internacional de mercadorias por estrada

U.S. regulations

  • 49 U.S.C. 14706 (Carmack Amendment): liability of motor carriers for loss and damage to cargo
  • 49 CFR Part 370: principles and practices for the investigation and voluntary disposition of loss and damage claims
  • Montreal Convention (1999): international air carriage, liability limits for cargo

Frequently asked questions

What is dimensional (DIM) weight?

DIM weight is the weight a carrier assigns to a package based on the space it takes: volume in cubic inches divided by the DIM divisor. You are billed on the larger of actual (scale) weight and DIM weight, the chargeable weight. Light, bulky items such as foam, furniture and appliances often bill on DIM weight.

Which DIM divisor should I use?

The one in your contract or the carrier service guide. UPS and FedEx use 139 in³/lb for daily rates, USPS and many retail rates use 166, IATA air freight uses 6,000 cm³/kg (about 166 in³/lb) and ocean LCL bills 1 metric ton per cubic meter. Negotiated contracts often raise the divisor to 166 or 194; change the field and the page updates.

How should I measure packages?

Measure the finished package at its widest points: handles, bulges and the pallet count. Carriers measure to the nearest inch and round up, and many round the result up to the next pound. Under-measuring usually comes back as an audit adjustment on the invoice.

How do I read the example result?

The 32 packages total 65.46 ft³ and 1,121 lb actual weight. With divisor 139 the DIM weight is 814 lb, lower than the actual weight, so the shipment bills on 1,121 lb. At $1.10 per chargeable pound the estimated freight is $1,233.10.

Per shipment or per package: what is the difference?

Per shipment compares totals, so dense items like the fastener boxes offset bulky ones like the foam packs. Per package, each box pays the larger of actual and DIM weight and the sum is never lower. In the example, chargeable weight rises from 1,121 lb per shipment to 1,512 lb per package, which is how most parcel carriers bill.

What is the freight split by item for?

It allocates total freight in proportion to the weight each item makes the carrier bill, so you know the freight cost inside each delivered product. In the example the fastener boxes carry 47% of the bill, while each foam pack carries only $9.90 because the shipment is billed on actual weight. Switch to per-package billing to see how the split changes.

What are the limits of this calculator?

Freight is a linear estimate: real rates have zones, weight breaks, fuel and residential surcharges, additional handling and oversize fees, and in LTL the NMFC freight class, none of which are modeled. Dimensions are not rounded automatically. Use it to compare packaging and quotes, and confirm the final amount with the carrier rate.