The secret to shipping small, heavy items cheaply. Ship up to 20 lbs for the price of a tiny package. Perfect for jewelry, coffee, cosmetics, and more.
No credit card required • No monthly fees • No contracts
Priority Mail Cubic is USPS's best-kept secret. Instead of paying by weight, you pay based on the size of your package. This means a 20 lb package costs the same as a 1 lb package if they're the same size!
Small, heavy items that fit in boxes under 0.5 cubic feet (roughly shoebox-sized or smaller). Ideal for jewelry, cosmetics, coffee beans, candles, small electronics, supplements, and subscription boxes.
Want to see exact rates for your package?
Calculate Your RateShip up to 20 lbs for the same price. Perfect for heavy items in small boxes.
1-3 day delivery with full tracking and $100 insurance included.
From 0.1 to 0.5 cubic feet. Smaller boxes = lower rates.
Same insurance coverage as regular Priority Mail at no extra cost.
Cubic rates work best with custom boxes sized to your products.
Schedule free USPS pickup from your location.
Get access to discounted USPS rates in under 5 minutes
Sign up in 30 seconds. No credit card or commitment required.
Input your package dimensions and destination to see instant rates.
Purchase your discounted label and schedule a pickup or drop off.
Priority Mail Cubic is a special USPS pricing tier where you pay based on package dimensions instead of weight. A 20 lb package costs the same as a 2 lb package if they fit in the same size box.
Packages must be 0.5 cubic feet or less (about the size of a shoebox). Maximum dimensions are 18 inches on any side. Weight limit is 20 lbs.
Multiply Length x Width x Height in inches, then divide by 1,728. Atoship automatically calculates this for you and shows if Cubic is the best rate.
Cubic pricing is only available through USPS-authorized shipping platforms like Atoship. It's not offered at Post Office retail counters.
Small but heavy items: jewelry, cosmetics, coffee beans, candles, supplements, small electronics, and anything dense that fits in a small box.
No, Cubic requires your own packaging or regular Priority Mail boxes. Flat Rate boxes have their own pricing structure.
Join 50,000+ sellers who save up to 89% on every shipment. No monthly fees, no hidden costs, no contracts.
No credit card required • Ship your first package in 5 minutes