Does USPS charge by weight or size?

USPS charges based on the greater of the actual weight or the dimensional weight. If your package is large but light (over 1 cubic foot), you will likely be charged based on its size (dimensional weight). Always measure your package to avoid surprise fees.

What is the cheapest way to ship a 5 lb package?

For a 5 lb package, USPS Ground Advantage is typically the cheapest option, especially for nearby zones. If shipping cross-country (Zone 8), a Priority Mail Flat Rate Medium Box might be cheaper if the item fits inside.

How do I find my USPS Zone?

The zone depends on the distance between the 'Origin Zip Code' and the 'Destination Zip Code.' You can find the exact zone using the USPS Domestic Zone Chart. Zones range from 1 (local) to 9 (freely associated states).

Are these rates exact?

The rates provided by this calculator are estimates based on 2024 Retail Pricing. The actual price you pay at the counter may vary slightly due to fuel surcharges, non-standard fees, or recent rate adjustments.

USPS Price Calculator - Estimate Shipping Costs

Written by Jurica Šinko•Category: Shipping & Freight

Understanding USPS Pricing in 2024

Navigating the United States Postal Service (USPS) pricing structure can be complex. Whether you are a small business owner shipping products daily or an individual sending a one-time care package, understanding how postage is calculated is essential for saving money. Our USPS Price Calculator provides instant estimates for the most common domestic shipping services: Ground Advantage, Priority Mail, and Priority Mail Express.

Shipping costs are no longer just about weight. Factors like dimensional weight, destination zones, and service speed all play a critical role in the final price tag. This guide will break down these concepts to help you choose the most cost-effective option for your needs.

How to Use This Calculator

Getting an accurate shipping estimate is simple with our tool. Follow these steps:

Enter Package Weight: Input the weight of your package in pounds and ounces. Be precise—even a fraction of an ounce can bump you into the next price tier.
Select Destination Zone: Choose the USPS Zone (1-9) corresponding to the distance between your zip code and the recipient's. If you don't know the zone, use the official USPS Zone Lookup tool.
Input Dimensions: Enter the length, width, and height of your package in inches. This is crucial for calculating dimensional weight, which can significantly increase costs for large, lightweight boxes.
Calculate: Click the "Calculate Rates" button to see a comparison of Ground Advantage, Priority Mail, and Priority Mail Express rates.

Key Factors That Affect USPS Shipping Costs

1. Weight and "Billable Weight"

USPS charges based on the "billable weight" of your package. This is the greater of the actual scale weight or the dimensional (DIM) weight.

Actual Weight: The physical weight of the package as measured on a scale.
Dimensional Weight: A calculated weight that reflects the amount of space a package occupies in a truck or plane. It is calculated as (Length x Width x Height) / 166 for retail shipments.

For example, if you ship a large pillow that weighs 2 lbs but measures 18" x 18" x 18", the volume is 5,832 cubic inches. Dividing by 166 gives a dimensional weight of roughly 36 lbs. You will be charged for the 36 lbs rate, not the 2 lbs rate. This is why optimizing your packaging size is the #1 way to reduce shipping costs.

2. USPS Zones

The distance your package travels is measured in "Zones," ranging from Zone 1 (local) to Zone 9 (freely associated states). The further the zone, the higher the cost.

Zone 1-2: Local shipments (within ~150 miles).
Zone 8: Cross-country shipments (e.g., New York to California).
Zone 9: U.S. territories like Guam or Puerto Rico.

Knowing your zone is critical for budgeting. A 5 lb package might cost $10 to ship to Zone 2 but over $25 to ship to Zone 8.

USPS Service Levels Compared

USPS Ground Advantage

Replaced "First-Class Package Service" and "Retail Ground" in 2023. This is the most economical option for packages up to 70 lbs.

Speed: 2-5 business days.
Best For: Non-urgent shipments, e-commerce orders, and heavy items where speed is not a priority.
Insurance: Includes $100 of insurance coverage.

Priority Mail

The standard for fast, reliable shipping.

Speed: 1-3 business days.
Best For: Time-sensitive documents and merchandise.
Flat Rate Options: Priority Mail also offers "Flat Rate" boxes (Small, Medium, Large) where the weight doesn't matter—if it fits, it ships. Our calculator estimates weight-based Priority Mail, which is often cheaper than Flat Rate for short distances.

Priority Mail Express

The fastest domestic service available.

Speed: Overnight to 2-day guarantee.
Best For: Urgent documents, perishables, and last-minute gifts.
Cost: Significantly more expensive than standard Priority Mail.

Pro Tips for Saving on USPS Shipping

💡 Expert Strategy: Use Cubic Pricing

Did you know there's a secret "Cubic" pricing tier for small, heavy packages? It's not available at the retail counter, but you can access it through third-party shipping software like Pirate Ship or Stamps.com. If your package is small (less than 0.5 cubic feet) but heavy (up to 20 lbs), Cubic pricing can save you up to 40% compared to standard weight-based rates.

Here are more ways to lower your shipping bill:

Buy Labels Online: Retail rates (what you pay at the Post Office counter) are significantly higher than "Commercial Base" rates available online. Using a service like PayPal Shipping, eBay, or Shopify can instantly save you 15-30%.
Use Poly Mailers: For non-fragile items like clothing, use a poly mailer instead of a box. They add negligible weight and volume, helping you avoid dimensional weight charges.
Check Flat Rate vs. Regional Rate: Don't blindly use Flat Rate boxes. For nearby zones (1-4), using your own box is often cheaper. Flat Rate is usually the winner only for heavy items going to Zone 7 or 8.

USPS Price Calculator - Estimate Shipping Costs