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USPS Shipping & Postage Calculator
Instantly calculate USPS postage and shipping rates, compare services, and unlock up to 87% off — all with ShipStation.
Whether you’re shipping a single First Class envelope or managing high-volume eCommerce orders, ShipStation’s USPS Shipping & Postage Calculator helps you get fast, accurate quotes — and save more on every label.
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- Real-time USPS postage estimates
- Compare USPS Ground Advantage®, Priority Mail®, First-Class®, and more
- Access discounted commercial rates — no volume required
- Print labels, schedule pickups, and manage all your shipping in one place
Start calculating now →
How to Use the USPS Shipping & Postage Calculator
Get a quick USPS shipping estimate in 3 easy steps:
- 1. Enter your origin and destination ZIP codes
- 2. Input package weight and dimensions
- 3. Compare USPS services and rates instantly
Pro tip: Accurate package dimensions matter. Oversized or underfilled boxes may trigger dimensional weight pricing.
Compare USPS Shipping Services
Not sure which USPS service is right for your shipment? Here’s a breakdown of the most common USPS services supported by ShipStation.
| Service | Delivery Time | Weight Limit | Price (starting from) | Best For |
|---|---|---|---|---|
| Ground Advantage | 2–5 business days | Up to 70 lbs | $6.98 | Everyday shipping |
| First-Class Mail® | 1–5 business days | Up to 13 oz | $4.75 | Envelopes, postcards, small parcels |
| Priority Mail® | 1–3 business days | Up to 70 lbs | $8.25 | Packages with tracking |
| Priority Mail Express® | Overnight–2 days | Up to 70 lbs | $26.95 | Urgent shipments |
| First Class Intl® | 7–21 days | Up to 4 lbs | Varies | Budget international shipping |
Ready to see your rate? Try the USPS Shipping Calculator now and access exclusive ShipStation discounts.
Access Low USPS Shipping Rates & More
Why Use ShipStation to Calculate USPS Rates?
Unlike the USPS website or other shipping tools, ShipStation’s calculator does more than just give you a number. Key Benefits:
Want to go beyond rates? Discover how ShipStation simplifies your entire shipping process — from orders to delivery.
Tips to Save on USPS Shipping
Small changes = big savings. Here’s how to reduce your USPS shipping costs:
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- Use the smallest box possible: Avoid dimensional weight surcharges.
- Leverage Flat Rate options: Especially for small and heavy items.
- Compare rates for every shipment: ShipStation does it automatically.
- Use USPS Ground Advantage for non-urgent deliveries.
- Batch print to save time and cost on high-volume shipping days.
USPS Shipping & Postage Calculator – FAQs
How to calculate shipping costs with USPS?
You’ll need the package’s weight, dimensions, origin and destination ZIP codes, and desired service level (e.g., Priority Mail or Ground Advantage). You can use a USPS shipping calculator or a platform like ShipStation to do this automatically.
How are USPS shipping costs calculated?
USPS calculates rates based on:
- Package weight
- Size/dimensions (for dimensional pricing)
- Shipping zone (distance from origin to destination)
- Service selected (Ground, Priority, Express)
- Packaging type (e.g., Flat Rate, custom box)
Does USPS charge by weight or size?
The USPS charges by both weight and package size. While there are generally weight thresholds that determine rates, there are more factors to be aware of. If packages are small but heavy, they may receive cubic pricing discounts. Conversely, if a package is lightweight but large, dimensional weight may increase the rates. For a full breakdown of ShipStation’s USPS rates, read our guide to USPS rates.
How to calculate USPS shipping cost by weight?
USPS uses weight tiers (e.g., up to 4 oz, 8 oz, 1 lb, etc.). Once your item exceeds 1 lb, zone-based pricing applies. Enter the weight in a tool like ShipStation’s calculator and it will return the rate by service type. For heavier packages, consider Flat Rate options.
How do I calculate USPS international shipping?
Enter your destination country, package weight, and dimensions into a USPS International Shipping Calculator or ShipStation. Rates depend on the destination, size, service (First-Class Intl, Priority Mail Intl, etc.), and whether customs forms or HS codes are required.
How to calculate USPS shipping costs for small businesses?
Use ShipStation’s calculator to get commercial pricing with no volume minimums. The platform simplifies calculation by syncing your orders and applying the best USPS rate automatically — especially useful when shipping across multiple zones or marketplaces.
How do I get USPS commercial rates?
Just sign up for ShipStation. All users instantly access Commercial Base Pricing with no volume requirements.
What is the best way to send items weighing less than one pound?
USPS First Class Mail is the most economical shipping option for any parcel weighing less than 16 oz. First Class Mail offers tracking and quick delivery times comparable to Priority Mail.
What is the best way to send items weighing more than one pound?
USPS Priority mail offers an affordable option for sending items weighing 1-10 lbs. For some parcels in this weight range being shipped to further zones as well as even heavier parcels, UPS and FedEx Ground offer affordable rates to quickly ship your parcels within the US.
How large can an envelope be and still be eligible for First-Class Mail letter rates?
USPS First Class Large Envelopes and Flats can have a height ranging from 6 ⅛” and 12”, a length between 11 ½” and 15”, and a thickness of ¼” and ¾”. The maximum weight for a First Class Large Envelope or Flat is 13 oz.
How is USPS Postage calculated?
A parcel’s weight and dimensions are combined to calculate the rate and available services and the origin zip code and destination zip code and corresponding USPS Zone also determine the final label fee.
What is the cheapest way to ship with USPS?
Whether you are shipping a letter weighing less than one ounce, a large envelope weighing up to 13 ounces, or a package weighing up to 16 ounces, First Class mail is the most affordable shipping option available.
If you want to get great discounts on these services as well as USPS Media Mail, Priority Mail, Parcel Select, and more, sign up for a ShipStation trial now and start saving time and money on your shipping.
If you want to get great discounts on these services as well as USPS Media Mail, Priority Mail, Parcel Select, and more, sign up for a ShipStation trial now and start saving time and money on your shipping.
Ready to Get the Best USPS Rates?
Whether you ship 5 packages a month or 500, ShipStation’s USPS calculator makes it easy to get the best rates — and manage your entire shipping process in one place. Want to ship smarter?