Estimate domestic postage costs based on weight, zone, and service type.
Zone 1 (Local, < 50 miles)
Zone 2 (51-150 miles)
Zone 3 (151-300 miles)
Zone 4 (301-600 miles)
Zone 5 (601-1000 miles)
Zone 6 (1001-1400 miles)
Zone 7 (1401-1800 miles)
Zone 8 (1801+ miles)
Zone 9 (Freely Associated States)
USPS Ground Advantage™ (2-5 Days)
Priority Mail® (1-3 Days)
Priority Mail Express® (Next Day)
Media Mail (Books/Media only)
Standard Package / Box
Large Envelope / Flat
Oversized Package (>108″ combined length+girth)
Total Weight:–
Service Level:–
Zone:–
Estimated Retail Price
$0.00
*Note: This tool provides estimates based on retail pricing formulas. Actual USPS rates vary based on exact dimensions, commercial discounts, and daily fuel surcharges.
Understanding the USPS Postage Rate Calculator
Calculating shipping costs accurately is essential for small business owners, eBay sellers, and anyone looking to send a package via the United States Postal Service. The cost of shipping is rarely a flat fee; instead, it is a dynamic calculation based on four primary factors: weight, distance (zone), speed of delivery (service class), and package dimensions.
Pro Tip: Always round your weight up to the nearest ounce. If a package weighs 5.1 oz, USPS charges for 6 oz. Under-weighing packages can result in "Postage Due" charges for the recipient or the package being returned to you.
Key Factors That Influence Your Shipping Rate
1. Weight and Dimensional Weight
Weight is the most obvious factor. USPS calculates rates in pounds and ounces. For lighter items (under 1 lb), USPS Ground Advantage (formerly First Class Package) is often the most economical choice. Once a package exceeds 1 lb, it must be shipped via Priority Mail or Ground Advantage at a higher tier.
However, physical weight isn't the only metric. Dimensional Weight (DIM Weight) applies to large, lightweight packages. If your box is large but light (like a box of pillows), USPS may charge you based on the volume of the box rather than the scale weight. This generally applies to packages larger than one cubic foot.
2. USPS Zones (Distance)
The USPS divides the United States into "Zones" based on the distance from the sender's zip code to the recipient's zip code.
Zone 1: Local shipments (within 50 miles).
Zone 8: Cross-country shipments (over 1,801 miles).
Zone 9: U.S. territories and Freely Associated States.
The further the zone, the higher the shipping rate. A 5lb box sent to Zone 1 might cost $10, while the same box sent to Zone 8 might cost $25.
3. Service Classes
Choosing the right service class allows you to balance cost versus speed:
USPS Ground Advantage™: The standard affordable option for packages up to 70 lbs. Delivery typically takes 2-5 business days. It includes $100 of insurance.
Priority Mail®: Faster delivery (1-3 business days) with flat-rate options available. This is often the standard for e-commerce.
Priority Mail Express®: The fastest option, offering overnight to 2-day delivery guarantees with a money-back guarantee.
Media Mail: A restricted, low-cost service strictly for books, sound recordings, and educational media. It is slow and subject to inspection.
Retail vs. Commercial Pricing
The rates displayed at the Post Office counter are known as Retail Rates. However, high-volume shippers and users of online shipping software (like Stamps.com, Pirate Ship, or eBay shipping) often access Commercial Pricing. Commercial rates can be significantly cheaper—sometimes up to 40% less—than the retail rates shown in estimators intended for general public use.
How to Use This Estimator
To get the most accurate estimate using the tool above:
Weigh your item: Use a kitchen scale or postage scale. Enter the pounds and remaining ounces separately.
Determine the Zone: If you don't know the specific zone, estimate based on distance. Local is Zone 1, neighboring states are usually Zone 3-4, and coast-to-coast is Zone 8.
Select Service: Choose how fast you need the item to arrive.