A girth calculator finds the distance around the thickest part of a package, which carriers define as 2 × width + 2 × height, and then adds the longest side to get “length plus girth,” the figure UPS and USPS use for their size limits. A 20 × 12 × 10 inch box, for example, has a girth of 44 inches and a length plus girth of 64 inches.
Enter your box’s dimensions below to get both numbers, then check them against the carrier limits in the tables that follow. The guide also shows how to measure correctly and which thresholds trigger extra handling charges.
Package girth calculator (inches)
Enter all three dimensions, rounded up to the next whole inch.
What Is Package Girth and Why Does It Matter?
Girth is the measurement around a package at its widest point, perpendicular to its length. Carriers combine it with length because a long, thin tube and a fat, short box can weigh the same yet take up very different space on a belt or in a truck.
The UPS Tariff/Terms and Conditions of Service defines it in exactly these words: girth is “(2 x width) + (2 x height),” and length is the longest side of the package. USPS uses the same definition, so one calculation works for both carriers. Our glossary of logistics terms and definitions covers related measurements like dimensional weight.
How Do You Calculate Girth Step by Step?
You only need a tape measure and the three dimensions of the packed box. Measure the outside of the box, including any bulge from the contents.
- Measure all three sides and round each up to the next whole inch, as carriers do.
- Name the longest side the length. The other two are width and height, in either order.
- Calculate girth: add width and height, then double the result (2 × width + 2 × height).
- Add length to girth to get length plus girth.
- Compare the result with the carrier limits below.
Rounding and identifying the longest side are where most mistakes happen. Our guide to how to read dimensions explains the order carriers expect, and our girth calculator in inches and cubic inches guide covers the volume side of the same measurements.
What do girth calculations look like for common boxes?
| Box (L × W × H, inches) | Girth | Length + girth | Size status |
|---|---|---|---|
| 12 × 10 × 6 | 32 | 44 | Well within UPS and USPS limits |
| 20 × 12 × 10 | 44 | 64 | Within limits |
| 30 × 20 × 18 | 76 | 106 | Over 105 inches: UPS Additional Handling |
| 36 × 24 × 24 | 96 | 132 | UPS Large Package; over the USPS 130-inch maximum |
| 48 × 6 × 6 (tube) | 24 | 72 | Under girth limits, but the 48-inch length triggers USPS nonstandard length fees |
What Are the UPS and USPS Girth Limits?
USPS caps most services at 108 inches in combined length and girth, while USPS Ground Advantage accepts up to 130 inches. UPS accepts packages up to 165 inches in length plus girth and 108 inches in length, with surcharges starting well before those maximums.
| Carrier and service | Maximum length + girth | Maximum weight | Size thresholds that add charges |
|---|---|---|---|
| USPS Priority Mail and Priority Mail Express | 108 inches | 70 lbs | Length over 22 or 30 inches; volume over 2 cubic feet |
| USPS Ground Advantage | 130 inches | 70 lbs | Over 108 inches is oversized pricing; same length and volume fees |
| UPS Ground and air services | 165 inches (108-inch max length) | 150 lbs | Additional Handling over 105 inches; Large Package over 130 inches or length over 96 inches |
UPS also applies Additional Handling to any package whose longest side is over 48 inches or whose second-longest side is over 30 inches, regardless of girth. The USPS figures come from the USPS Ground Advantage page and the USPS mail and shipping services page.
How Is Girth Different From Dimensional Weight?
Girth decides whether a package is allowed and whether size surcharges apply, while dimensional weight decides how much weight you’re billed for. They use the same three measurements but answer different questions.
USPS calculates dimensional weight for packages larger than 1 cubic foot (1,728 cubic inches) by multiplying length × width × height and dividing by 139, then bills whichever is greater, the actual or dimensional weight. The actual weight here is the packed gross weight, box and packing material included, and our guide to gross weight vs net weight explains the difference. A box can be well under every girth limit and still bill far above its scale weight, which is why our shipping box size calculators guide focuses on choosing the smallest box that fits. Box strength matters too, and our explainer on 32 ECT box strength explains the rating, while sellers sending inventory to Amazon should check Amazon box sizes and FBA carton limits.
How Can You Keep Girth Under the Limits?
The easiest savings come from packing tighter. Small changes to the box often move a package back under a threshold.
- Trim empty space. Cut down or score a box that’s taller than its contents.
- Split long or bulky items into two boxes when one would cross 105 inches with UPS or 108 inches with USPS.
- Measure after packing. Overstuffed boxes bulge, adding inches to the girth.
- Consider freight for very large items. Beyond parcel limits, an LTL shipment priced by freight class may be simpler, and our freight class calculator tips and guide to LTL freight rates explain how. You can get a pallet quote in the PalletPath LTL freight quote tool.
Once you know your dimensions, enter them in the ParcelPath rate calculator to compare UPS and USPS for the exact box. ParcelPath is free to use, with up to 85% off UPS and up to 89% off USPS. For delivery timing, our roundup of shipping time calculators compares tools that estimate transit days, and our shipping calculator guide explains every input a rate quote uses.
Frequently Asked Questions
How do you calculate girth for a package?
Measure the box and treat the longest side as the length. Girth is two times the width plus two times the height. For a 20 × 12 × 10 inch box, girth is 2 × 12 + 2 × 10 = 44 inches. Add the length to get length plus girth, which is 64 inches for that box.
What is the maximum girth for USPS packages?
USPS limits most services, including Priority Mail and Priority Mail Express, to 108 inches in combined length and girth. USPS Ground Advantage accepts packages up to 130 inches, with oversized pricing for packages over 108 inches. Every USPS service has a 70-pound weight limit.
Does length count when calculating girth?
No. Girth uses only the two shorter sides: 2 × width + 2 × height. Length, the longest side, is added afterward to get length plus girth, the number carriers compare against their limits. Using the wrong side as length is the most common girth mistake.
When does UPS charge for package size?
UPS applies Additional Handling when length plus girth exceeds 105 inches, the longest side exceeds 48 inches or the second-longest side exceeds 30 inches. A package becomes a Large Package when length plus girth exceeds 130 inches or length exceeds 96 inches. The maximum is 165 inches in length plus girth.
Sources
- UPS Tariff/Terms and Conditions of Service (United States): girth definition, maximum size, Additional Handling and Large Package criteria
- USPS Ground Advantage: size and weight limits
- USPS Mail and Shipping Services: nonstandard fees and dimensional weight
- USPS Domestic Mail Manual 201: physical standards for parcels
Part of our How to Read Dimensions guide. Related: 32 ECT Meaning, Amazon Box Sizes, Dimensions of Vinyl Record.
