USPS vs UPS for Heavy Packages
Comparing rates for heavy shipments where the cost gap closes
Side-by-Side Comparison
| Category | USPS | UPS | Winner |
|---|---|---|---|
| Price (10 lb package) | $12-18 | $14-20 | USPS |
| Price (20 lb package) | $18-28 | $18-25 | Tie |
| Price (40 lb package) | $30-50 | $25-40 | UPS |
| Flat Rate Option (Medium Box, any weight) | ~$16 Priority Mail | Not available | USPS |
| Max Weight | 70 lbs | 150 lbs | UPS |
| Dimensional Weight Pricing | Applied on large packages | Applied on all packages | USPS |
| Heavy Package Surcharge | None up to 70 lbs | Surcharge over 50 lbs | USPS |
| Delivery Speed (Ground) | 2-5 business days | 1-5 business days | UPS |
When to Use Each Carrier
USPS
- Heavy, dense items that fit in flat rate boxes
- Packages 10-20 lbs going short distances
- Shipments under 70 lbs to residential addresses
- Budget-conscious heavy package shipping
UPS
- Packages over 20 lbs going long distances
- Items between 70-150 lbs (exceeds USPS limit)
- Heavy business-to-business shipments
- Large, lightweight packages subject to dimensional weight
Detailed Breakdown
The conventional wisdom that USPS is always cheaper breaks down with heavy packages. While USPS dominates the lightweight segment, UPS becomes increasingly competitive as package weight rises above 10-15 lbs. For a 40 lb package shipped cross-country, UPS Ground can actually be cheaper than USPS by $5-10. One major factor is weight limits: USPS caps at 70 lbs while UPS accepts packages up to 150 lbs. If your package exceeds 70 lbs, UPS (or FedEx) is your only option among major carriers. However, USPS has a secret weapon for heavy packages: flat rate boxes. A 30 lb item that fits in a Priority Mail Medium Flat Rate Box ships for about $16, which is dramatically cheaper than weight-based pricing from any carrier. The catch is the item must physically fit inside the box. For heavy package shippers, the smartest approach is to always compare rates because the cheapest option varies significantly based on weight, size, and distance.
Frequently Asked Questions
UPS Ground typically becomes price-competitive with USPS around 15-20 lbs and can be outright cheaper for packages over 20 lbs, especially for long-distance shipments. The exact crossover point depends on package dimensions, origin, and destination. Always compare rates for your specific shipment.
USPS has a maximum weight limit of 70 lbs for all services. If your package weighs more than 70 lbs, you will need to use UPS (up to 150 lbs) or FedEx (up to 150 lbs). For items over 150 lbs, you will need freight shipping services.
USPS flat rate boxes are excellent for heavy, dense items. A Medium Flat Rate Box costs about $16 and a Large Flat Rate Box about $22, regardless of weight up to 70 lbs. If you can fit a 20 lb item in a Medium Flat Rate Box, you pay $16 instead of the $18-28 you would pay for weight-based shipping. The key limitation is the item must fit in the box.
UPS applies an Additional Handling surcharge for packages over 50 lbs, which adds roughly $12-15 to the shipping cost. Packages over 70 lbs incur an even higher surcharge. These surcharges apply on top of the base rate and are one reason USPS can still compete for packages in the 20-50 lb range.
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