Sellers are responsible for paying overage charges for oversize or overweight packages. Shipping carriers charge overage fees to deliver packages that are over the weight and/or dimension limits on the shipping label. If the prepaid shipping label is insufficient based on the package’s weight and size then: (i) the package may be returned to the seller or (ii) oversize or overweight fees will be charged and the additional fees deducted from your sales.

Avoid estimating your package’s weight and size and provide accurate measurements when selecting a prepaid label. If you significantly underestimate the size or weight of the package, you may even not receive any profits from your sale.

Understanding heavy or overweight charges

If you’ve been charged for an overweight package, your package weighed more than the weight class selected for your prepaid label. This happens when your package's actual weight and /or dimensional (DIM) weight exceeds the weight selected for your purchased postage.

Final package weight is determined based on multiple factors, not just the actual weight. Factors include shipping carrier (USPS, FedEx, UPS), shipping class, package dimensions, actual weight and DIM weight.

What is ‘actual weight’?

Actual weight is the amount (in ounces or pounds) a package weighs determined by a scale that measures mass. For example, postage scales measure actual weight. When selecting a Mercari prepaid label, sellers are required to input the actual package weight.

What is DIM weight?

DIM weight, or dimensional weight, is the size of a package in relation to its actual weight. DIM weight helps certain carriers calculate a shipping rate based on how much space a package will occupy on a delivery truck. Carriers that use DIM weight will charge based on the greater of the actual weight or DIM weight.

When using prepaid labels, Mercari recommends inputting weight, length, width and height for the most accurate weight class.

How is DIM weight calculated?

DIM weight is calculated by multiplying a package’s length x width x height and dividing that sum by a carrier’s designated shipping divisor*.

*Mercari prepaid labels use shipping divisors set by the carrier. 139 is an example shipping divisor.

DIM Weight Calculation:

Example

Package dimensions: Length: 12”, Width: 5”, Height: 8”
Example shipping divisor: 139

How do carriers calculate shipping weights?

Each carrier has their own approach to rate calculation based on package size. USPS uses actual weight to calculate shipping rate. FedEx and UPS consider actual weight and DIM weight but will select the highest to determine the shipping rate.

When does DIM weight exceed actual weight?

Say you’re shipping a large plush toy that is fluffy and lightweight. The plush toy weighs 2 lbs with packaging. You package the plush toy in a box with the following measurements: 12” Length x 12” Width x 8” Height.

Although the package weighs only 2 lbs, the dimensional weight is about 8.3 lbs. This is calculated by multiplying the length x width x height and dividing that sum by the carrier’s shipping divisor (example is 139).

Tip: Enter all measurements - actual weight, package length, width, height - and Mercari will recommend the best shipping method.

Understanding heavy or overweight charges

Oversized packages or packages with incorrect dimensions may be subject to additional postage fees with the carrier (USPS, UPS, FedEx). Fees vary by carrier. Sellers are responsible for all fees associated with oversized packages or packages with incorrect dimensions which will be deducted from the seller’s earnings.

USPS Fees

USPS charges a Nonstandard Fee for USPS packages that exceed a certain dimensional threshold. Nonstandard fees include:

• $4.00 Surcharge for parcels longer than 22 inches but less than 30 inches
• $15.00 surcharge for parcels longer than 30 inches in length
• $15.00 surcharge for parcels measuring greater than 2 cubic feet (3456 cubic inches)

USPS also applies a fee of $1.50 to packages with incorrect or missing dimensions (length, width, height) that also have a length greater than 22 inches or volume greater than one cubic foot.

For more information, please review additional details on the USPS website.

Other reasons for additional charges

FedEx Ground® Economy

All FedEx packages, including FedEx Ground® Economy packages, must be dropped off at a FedEx location or at a designated FedEx drop off location. Your package cannot be larger than 12” x 8” x 4” and the shipping weight can’t exceed 5 lbs. Sellers are responsible for all fees associated with incorrect drop-off or overweight packages which will be deducted from the seller’s earnings.

Click here to find the nearest FedEx drop off location.

Duplicate labels

All packages are scanned by the applicable shipping carriers. When a label is used more than once, they charge Mercari for additional postage which Mercari will then charge to the seller by deducting the amount from the seller’s earnings. Be sure to only use a shipping label once to avoid any additional fees.

Improper boxes

Be sure to use the right box for your label. When you’re shipping with a USPS First-Class label, don’t use a USPS Priority Mail box. There is an additional fee when the carrier has to repackage the item during transit.

Sellers will be charged for these types of shipping surcharges for using an incorrect box and the surcharges will be deducted from the seller’s earnings.

Choosing the best label

Shipping carriers charge based on the package's weight and size.

The carriers will charge postage due fees to deliver packages that are over the weight and/or dimension limits on the shipping label.

Please make sure that you choose the correct label so your item arrives safely to the buyer. Sellers will be responsible for paying any oversize or overweight fees so the buyer doesn’t have to pay them. If the prepaid shipping label is insufficient based upon the package’s weight and size then: (i) the package may be returned to the seller or (ii) oversize or overweight fees will be charged and the additional fees deducted from your sales.

Choose the right label for your package’s size and weight to help keep the marketplace fair and shipping labels affordable.