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. If the actual weight or dimensional weight is for a Mercari provided label (see Fees), you will be charged that weight less the amount already paid. If Mercari does not provide a label for that weight, then the carrier residential retail rates for zone 7 will apply less the amount already paid. If the package weighs more than 150 pounds, then we include the carrier oversize fee.
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.
Packages over one pound are always rounded up to the nearest pound. For example, an item that weighs 3.25 lb will require a 4 lb label.
How is the additional shipping cost calculated?
If the actual weight or dimensional weight provided by the shipping carrier is higher than the label used for a Mercari provided label (see Fees on Mercari), you will be charged that weight less the amount already paid plus 8% fee. If Mercari does not provide a label for that weight, then the carrier residential retail rates for zone 7 including all surcharges and an 8% fee will apply less the amount already paid. If it is over 150 pounds in actual weight or dimensional weight, it will be billed at a flat rate of $2,500.
Starting March 10, 2025, items exceeding the purchased label’s actual weight or dimensional (DIM) weight will incur an 8% penalty fee on the total adjusted shipping price. The additional shipping charges are assessed while the package is in transit when the shipping carrier provides the actual weight or/and dimensional weight.
Available Mercari shipping labels:
For USPS shipping weights over 20 pounds will be billed in increments of 10 pounds, so a 12 lb will be billed at 20 lb. For FedEx and UPS shipping weights over 50 pounds will be charged in increments of 10 pounds.
Understanding heavy or overweight charges
If you’ve been charged for an overweight package, the shipping carrier informed us that 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*, rounding up to the nearest pound.
*Mercari prepaid labels use shipping divisors set by the carrier. 139 is an example shipping divisor.DIM Weight Calculation:
Example
3.45 lb dim weight = 4 lb package
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 up to one cubic foot (12”x12”x12”). FedEx and UPS consider actual weight and DIM weight but will select the highest to determine the shipping rate. During the shipping journey, the carrier will weigh and scan the package, this is shared with Mercari and this is what we use to determine additional shipping cost.
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 lb 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 lb, the dimensional weight is about 8.3 lb. 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.
Shipping Surcharge Fees
In addition to the label cost, each carrier have different surcharges that may apply, see below:
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 lb. 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.
UPS Ground Saver (formerly SurePost)
All UPS packages, including UPS Ground Saver (formerly SurePost) packages, must be dropped off at a UPS location or at a designated UPS drop off location. Your package cannot be larger than 16” x 8” x 16” and the actual or dimensional weight can’t exceed 5 lb. Sellers are responsible for all fees associated with incorrect drop-off or overweight packages which will be deducted from the seller’s earnings. Packages dropped off at the wrong carrier is the responsibility of the seller. Shipping Protection will not be provided.
Click here to find the nearest UPS drop off location.
FedEx Economy and UPS SurePost (now UPS Ground Saver) packages dropped off at USPS Post Offices or mail boxes will not be delivered and will be destroyed at the Seller’s expense.
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.
Reuse boxes
When re-using a box, you must completely remove all hazmat markings and stickers. We recommend turning the box inside out. Shipping carriers will hold packages with hazmat markings and will destroy them if not re-package. Sellers will be fully responsible for any repackaging cost or the loss. Mercari Shipping Protection will not apply.
Hazmat InformationChoosing 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.
Small packages up to one cubic foot (12”x12”x12”), you can base your label on weight for all shipping carriers.
Packages over one cubic foot, carriers will use the heavier of actual package weight or dimensional weight.
Some service types can only be used for specific items:
- First-Class Envelope for trading cards up to $20 Mercari Shipping Protection with limited tracking
- Media Mail for books up to $200 Mercari Shipping Protection up to 20 lbs and no larger than one cubic foot
