Introduction
Our free USPS Shipping Calculator helps you find the cheapest way to send a package through the United States Postal Service. Just enter your ZIP codes, package weight, and box size, and the tool shows you estimated rates for every USPS service side by side. It works for domestic mail and international shipping to 20 countries. You can compare prices for Priority Mail, Priority Mail Express, USPS Ground Advantage, flat rate envelopes, flat rate boxes, postcards, and letters — all in one place.
The calculator also figures out dimensional weight, which is what USPS charges when a box is large but light. It picks the higher number between actual weight and dimensional weight so you see the real cost. You can also use our Volumetric Weight Calculator to understand how carriers determine dimensional weight for any shipment. If your item is worth more than $100, it adds the insurance fee too. A bar chart and rate table make it simple to spot the best deal fast.
Whether you run a small business, sell items online, or just need to mail a gift, this tool saves you time and money. If you sell on platforms like eBay or Etsy, pair this calculator with our eBay Fee Calculator or Etsy Fee Calculator to understand your total costs before listing an item. Enter your details below to get started.
How to Use Our USPS Shipping Calculator
Enter your package details below to get estimated USPS shipping rates, delivery times, and the cheapest mailing option.
Domestic or International: Click the "Domestic" tab to ship within the U.S. or the "International" tab to ship to another country.
Mailing From (ZIP Code): Type the 5-digit ZIP code where you are sending the package from.
Mailing To (ZIP Code) or Destination Country: For domestic shipments, type the 5-digit ZIP code you are shipping to. For international shipments, pick the destination country from the dropdown list. If you are shipping internationally, our Flight Time Calculator can help you estimate how long transit may take by air.
Planned Mail Date: Pick the date you plan to drop off your package. This must be today or a future date. You can use our Business Days Calculator to count exactly how many business days until your expected delivery.
Planned Mail Time: Choose the time of day you plan to mail your package.
Package Shape & Type: Select the type of item you are shipping. Choose "Postcard" for postcards, "Letter / Flat Rate Env." for letters or flat rate envelopes, "Flat Rate Box" for USPS flat rate boxes, or "Custom Package" for your own box or package. If you pick an envelope or box option, click the specific size you want.
Weight (lbs and oz): Enter your package weight in pounds and ounces. Ounces must be between 0 and 15.9. This field only shows for boxes and custom packages.
Length, Width, and Height (in): Enter your package dimensions in inches. These fields only show for custom packages. The calculator uses these to find the dimensional weight and compare it to the actual weight. If you need to convert metric measurements, our Meters to Feet Calculator can help. You can also use the Volume Calculator to double-check the cubic volume of your package.
Declared Item Value ($): Enter the dollar value of the items inside your package. If the value is over $100, an insurance surcharge will be added to each rate.
Calculate Button: Click "Calculate" to see your estimated USPS shipping rates. The tool shows the cheapest option, a full rate table, and a bar chart comparing all available services.
Reset Button: Click "Reset" to clear all fields and start over with the default values.
How USPS Shipping Costs Work
USPS (United States Postal Service) is the main mail service in the United States. It delivers letters, packages, and boxes to every address in the country and to most countries around the world. Millions of people and businesses use USPS every day because it is often the cheapest way to ship.
The price you pay to ship something with USPS depends on a few key things. Weight is the most important factor — heavier packages cost more to send. Distance also matters. USPS splits the country into shipping zones numbered 1 through 8. Zone 1 means the destination is close to you, and Zone 8 means it is far away. A higher zone means a higher price. Our Distance Calculator can help you understand the concept of distance between two points.
Package size can also change your cost. USPS uses something called dimensional weight (or DIM weight). If your box is large but light, USPS may charge you based on the size of the box instead of how much it actually weighs. They pick whichever number is bigger — the real weight or the DIM weight. For a deeper look at how carriers calculate this, try our Volumetric Weight Calculator. Understanding your package dimensions is essential — our Cubic Feet Calculator can help you convert between volume units when measuring boxes.
USPS offers several service levels. USPS Ground Advantage is the most affordable and takes 2 to 5 business days. Priority Mail is faster, usually 1 to 3 days. Priority Mail Express is the fastest option, arriving in 1 to 2 days. For items that weigh very little, First-Class Mail is the cheapest choice. If you are managing supply chain timelines, our Lead Time Calculator can help you plan when to place orders so shipments arrive on schedule.
If you do not want to weigh or measure your package, USPS also sells Flat Rate envelopes and boxes. With Flat Rate, the price stays the same no matter how much your item weighs or how far it goes — as long as it fits inside the envelope or box and meets the weight limit of 70 pounds.
For international shipping, USPS delivers to over 190 countries. International rates are higher than domestic rates and depend on the destination country. Delivery times range from about 3 days for express service to 21 days or more for standard service. Use our Date Duration Calculator to count the days between your mailing date and expected arrival.
If the item you are shipping is worth a lot of money, you can add insurance by declaring its value. USPS includes free coverage up to $100 on most services. Above that amount, there is a small extra fee to protect your package in case it gets lost or damaged. When selling online, knowing your total costs — including shipping, platform fees, and insurance — is key to profitability. Our Margin Calculator and Markup Calculator can help you set the right price so shipping costs do not eat into your profits. If you collect sales tax on your shipments, our Sales Tax Calculator can help you figure that out as well.