Shipping Cost by Weight.
From 1 oz to 70 lb.

Cheapest-carrier-per-weight is the question that drives this page's entire reason for existing. Carrier pricing isn't linear; each carrier has weight tiers where their network economics work best, and the rate sweet spots shift with every annual rate adjustment.

• 1 oz - 1 lb

  Cheapest: USPS Ground Advantage

  USPS owns this bracket. Ground Advantage starts at the price of a stamp; UPS and FedEx Ground both have weight floors that price them out of true small parcels.

• 1 lb - 5 lb

  Cheapest: USPS Ground Advantage / Priority

  Still USPS territory for short-to-medium distances. UPS Ground starts becoming competitive on coast-to-coast hauls in this bracket.

• 5 lb - 20 lb

  Cheapest: UPS Ground or FedEx Ground

  USPS Priority Mail loses its advantage here. UPS and FedEx Ground are usually $1-3 cheaper per parcel than Priority Mail by 10 lb.

• 20 lb - 50 lb

  Cheapest: UPS Ground

  Heavy parcel territory. UPS typically wins on rate; FedEx is competitive on speed. USPS Priority Mail caps at 70 lb but is rarely cheapest above 20 lb.

• 50 lb - 70 lb

  Cheapest: UPS Ground or FedEx Freight (for >70 lb)

  Near the per-parcel cap for USPS (70 lb max) and UPS/FedEx Ground (150 lb max each). Above 70 lb you're approaching LTL freight territory.

Carriers don't just charge for what your package weighs - they charge for the truck space it takes up. The formula: length × width × height ÷ a divisor (139 for UPS and FedEx domestic, 166 for USPS and most international). The result is "dimensional weight," and the carrier bills for whichever is larger - actual or dimensional.

Practical example: a 5 lb parcel in a 14×12×10 inch box has actual weight of 5 lb but dimensional weight of (14 × 12 × 10) ÷ 139 = 12.1 lb. UPS would bill the dim weight, so the rate you pay is the 12 lb price, not the 5 lb price. The calculator does this math server-side so your quote reflects the real billable weight.

Three honest levers that actually move the needle:

• Shrink the box.Cutting two inches off each dimension on a 5 lb dim-weight-billed parcel can drop the bill by $3-5 without changing what's inside. Vacuum-seal, fill less, ship in mailers when items aren't fragile.
• Pick the right carrier per bracket. Quote every shipment - don't lock into one carrier for everything. The 2-3 second quote-and-compare pays $1-5 per parcel back to you on average.
• Use commercial-tier rates. The retail rates you see on usps.com / ups.com / fedex.com are 10-30% higher than commercial. shiponline.app passes commercial rates through to every shipper without a volume commitment.

Per-parcel weight caps in case you're wondering whether a heavy shipment can go via standard parcel service or needs freight:

• USPS

  70 lb

• UPS Ground

  150 lb

• FedEx Ground

  150 lb

• DHL Express

  154 lb (70 kg)

Anything over the per-carrier cap moves into LTL (less than truckload) freight - a different service tier with different pricing. shiponline.app doesn't quote LTL yet; for heavier shipments use a freight broker.