To measure irregular freight for LTL, measure the box it would fit in: the greatest straight-line length, width and height of the handling unit, including every projection, as tendered to the carrier. That is how NMFTA defines the cube used for density, so the true volume of the shape does not matter for class; its outer extremes do (NMFTA, Calculating Density Best Practices (updated 21 October 2026)).
Why is irregular freight hard to measure?
A tape measure works well on flat faces and square corners. On a machine with a handle, a crate with skids, or a pallet with an uneven top, the extremes are easy to miss, and every missed inch makes the cube smaller and the density higher than the carrier will find. Since 19 July 2025 many more commodities are classed by density (NMFTA Disposition Bulletin 1371, Docket 2025-1 (21 March 2025)), so more irregular shipments are billed on that measurement.
What does the NMFC count as the dimensions?
The greatest dimension is the longest straight-line dimension of the handling unit as tendered for shipment (NMFTA, NMFC Classification Glossary of Terms (updated 16 March 2026)). Density uses the greatest straight-line length, width and height in inches, including all projections, divided by 1,728 for cubic feet, and the weight of the handling unit divided by that (NMFTA density guide). In other words: the rectangular box that encloses the whole unit.
Do not split an irregular item into sections and add their volumes, and do not use the volume of a 3D model of the shape. Both give a smaller cube than the one the carrier will measure.
How do you measure irregular freight step by step?
- Prepare the unit as it will ship. Pallet, crating, wrap and bracing in place.
- Length: find the two points furthest apart horizontally, including handles, flanges and overhang, and measure the straight line between them.
- Width: measure the widest point at right angles to the length, again including projections.
- Height: from the floor to the highest point of the unit, pallet included.
- Weight: the whole handling unit as tendered.
- Record and photograph the unit with the figures, so you can answer a carrier's re-measurement.
What difference does a missed projection make?
Take a machine on a 48 x 40 inch pallet, 50 inches high and weighing 600 pounds, with a handle that sticks out 6 inches past the pallet. Measured without the handle: 48 × 40 × 50 = 55.56 cubic feet and 10.8 pounds per cubic foot, class 92.5 on the standard scale. Measured correctly at 54 inches long: 62.5 cubic feet and 9.6 pounds per cubic foot, class 100 (Bulletin 1371). The carrier measures the second way.
| Sub | Density (pounds per cubic foot) | Class |
|---|---|---|
| 1 | Less than 1 | 400 |
| 2 | 1 but less than 2 | 300 |
| 3 | 2 but less than 4 | 250 |
| 4 | 4 but less than 6 | 175 |
| 5 | 6 but less than 8 | 125 |
| 6 | 8 but less than 10 | 100 |
| 7 | 10 but less than 12 | 92.5 |
| 8 | 12 but less than 15 | 85 |
| 9 | 15 but less than 22.5 | 70 |
| 10 | 22.5 but less than 30 | 65 |
| 11 | 30 but less than 35 | 60 |
| 12 | 35 but less than 50 | 55 |
| 13 | 50 or greater | 50 |
Can you reduce the cube of irregular freight?
Only by changing how it ships: removing or folding projections where the product allows, choosing a pallet that fits the footprint, or consolidating units. NMFTA's density guidance looks at product dimensions, packaging design and pallet configuration, and at when consolidation improves the density of a handling unit (NMFTA density guide). What you cannot do is measure the shape more tightly than its outer extremes.
Which tools help with irregular shapes?
A tape measure can be accurate if two people take the extremes carefully, but it is slow on awkward shapes and leaves no record unless you write one. Fixed dimensioners and LiDAR apps capture the outer extremes the same way every time. FreightSizer measures the unit with an iPhone or iPad LiDAR scanner, calculates density and determines the class in line with NMFTA guidelines, including the standards effective 19 July 2025; FreightSizer states a typical measurement error within 0.5–1 inch, depending on object size. More on overhang in mastering freight measurement with overhang and pallet dimensions.
Frequently Asked Questions
How do I measure the volume of freight that isn't a box?
Measure the greatest length, width and height, including all projections, and multiply them: the enclosing box, not the shape's own volume (NMFTA density guide).
Do protrusions count?
Yes. NMFTA's rule includes all projections (NMFTA density guide).
What if the irregular item ships with others on the same bill?
Calculate density for each handling unit, unless the shipping papers show only a total weight; then total weight and total cube may be used (NMFTA, How to classify a mixed-freight package, skid, or crate (updated 16 March 2026)).
How often do the NMFC rules change?
The NMFC is updated twice a year (NMFTA, Upcoming Key Dates for the NMFC Data Updates (updated 9 June 2026)). The largest recent change, Docket 2025-1, took effect on 19 July 2025 and moved many commodities to density-based classes (Bulletin 1371).