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.

- 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.

Calculate USPS Shipping Cost

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:

Access commercial pricing

Get discounted USPS rates automatically — no volume commitment.

Save time

Automate label printing and order syncing across marketplaces like Amazon, Shopify, eBay, and more.

Skip the trip

Schedule USPS pickups directly through ShipStation.

Batch shipments

Process hundreds of orders at once, with the best rate applied to each.

Want to go beyond rates? Discover how ShipStation simplifies your entire shipping process — from orders to delivery.

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Tips to Save on USPS Shipping

Small changes = big savings. Here’s how to reduce your USPS shipping costs:

- 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.

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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.

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?

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