Package Dimension Calculator
Calculate dimensional weight, shipping cost estimates, and girth for packages.
Compare USPS, UPS, and FedEx size limits.
Package Dimensional Weight is used by carriers to price shipments based on volume, not just actual weight. If the dimensional weight exceeds the actual weight, you pay based on the dimensional weight.
Dimensional Weight Formula:
Dim Weight (lbs) = (L × W × H) / DIM Factor
DIM Factors:
| Carrier | DIM Factor (inches) | DIM Factor (cm) |
|---|---|---|
| USPS | 166 | 5,000 |
| UPS | 139 | 5,000 |
| FedEx | 139 | 5,000 |
Girth Calculation:
Girth = 2 × (Width + Height)
Length + Girth = Length + 2 × (Width + Height)
Carriers limit “length + girth” — the longest side is the length, the other two sides form the girth.
Carrier Size Limits:
| Carrier | Max Length + Girth | Max Length | Max Weight |
|---|---|---|---|
| USPS Priority | 108 in (274 cm) | 108 in | 70 lbs (31.8 kg) |
| USPS Ground | 130 in (330 cm) | 108 in | 70 lbs (31.8 kg) |
| UPS | 165 in (419 cm) | 108 in | 150 lbs (68 kg) |
| FedEx | 165 in (419 cm) | 119 in | 150 lbs (68 kg) |
Billable Weight:
Billable Weight = MAX(Actual Weight, Dimensional Weight)
The carrier charges whichever is greater.
Practical Example: A box 24 × 18 × 12 inches, actual weight 8 lbs:
- UPS dim weight: (24 × 18 × 12) / 139 = 37.3 lbs
- Billable weight: 37.3 lbs (not 8 lbs!)
- Girth: 2 × (18 + 12) = 60 inches
- Length + girth: 24 + 60 = 84 inches — within all carrier limits
In metric: 61 × 46 × 30 cm, 3.6 kg actual:
- Dim weight: (61 × 46 × 30) / 5000 = 16.8 kg
- Billable weight: 16.8 kg
Tips:
- Use the smallest box possible to minimize dimensional weight charges.
- If your item is light but bulky, dimensional weight pricing can significantly increase cost.
- Flat-rate boxes (USPS) ignore dimensional weight — ideal for heavy, small items.
- Always measure the outside of the box, including any bulges.
- Round up each dimension to the nearest inch (or cm) as carriers do.