What is dimensional weight?
Dimensional weight (also called volumetric weight or DIM weight) reflects the space a parcel takes up in a truck, plane, or container. A large, light box, like a pillow, uses as much capacity as a heavy one, so carriers charge for the space.
What is the dimensional weight formula?
| Unit system | Formula |
|---|---|
| Metric | (L × W × H in cm) ÷ 5,000 = dimensional weight in kg |
| Imperial | (L × W × H in inches) ÷ 139 = dimensional weight in lb |
Divisors vary by carrier and service. 5,000 (cm) and 139 (in) are common for courier services, but always check your carrier’s current rate guide.
Worked example: metric
A box measures 50 × 40 × 30 cm and weighs 8 kg.
- Volume: 50 × 40 × 30 = 60,000 cm³
- Dimensional weight: 60,000 ÷ 5,000 = 12 kg
- Actual weight: 8 kg
- Billable weight: 12 kg
Worked example: imperial
A box measures 20 × 16 × 12 inches and weighs 15 lb.
- Volume: 20 × 16 × 12 = 3,840 in³
- Dimensional weight: 3,840 ÷ 139 = 27.6, rounded up to 28 lb
- Actual weight: 15 lb
- Billable weight: 28 lb
Carriers typically round up, and many measure each side to the next whole unit before calculating.
How does dimensional weight work for air freight and sea freight?
| Mode | Common rule of thumb |
|---|---|
| Courier / express | L × W × H (cm) ÷ 5,000 |
| Air freight (IATA standard) | L × W × H (cm) ÷ 6,000, so 1 m³ ≈ 167 kg |
| Sea freight LCL | Revenue ton: 1 m³ is treated as 1,000 kg, and the greater of weight or volume is charged |
How can you reduce dimensional weight charges?
- Right-size your boxes. Trimming a few centimetres off each side can drop a whole weight band.
- Use poly mailers for soft goods like apparel.
- Reduce void fill and stop shipping air.
- Compare carriers. Divisors differ, so the same box can cost less with another provider.
- Audit invoices. Check whether you were billed on the correct dimensions.
Key takeaway: You pay for the bigger of two numbers, actual weight or size-based weight. Light, bulky items are where DIM charges hurt most.
FAQ
Is dimensional weight the same as volumetric weight? Yes. The terms are interchangeable.
Do all carriers use the same divisor? No. Divisors vary by carrier, region, and service level.
Does dimensional weight apply to pallets? Yes. LTL and air freight carriers use volume-based calculations for palletised cargo.
Leave a comment