Shipping Calculations

Zonos Checkout and Zonos API support shipping rates calculation for different express carriers, postal carriers, and freight (LTL) as well as the ability to service custom service levels, transit times, rates, and more. For shipments originating from the United States, both pounds (lbs.) and ounces (oz.) can be used to calculate shipping.

Decoding cross-border shipping calculations

At a minimum, shipping calculations require a:

For anyone who has ever shipped internationally can attest, this gets notably more complex when you factor in:

All the above prevents many from even attempting cross border. Calculating international shipping costs does not have to be a guessing game or a manual process. Zonos’ API integrations, custom rate charts, proprietary rules engine, cartonization, and multi-carrier support make it simple to calculate cross-border shipments and allows you more time to focus on other aspects of your business.

Carrier API integrations

Zonos gives you the ability to connect directly with your carrier’s API to pull your negotiated rates. We support a direct integration with UPS, FedEx, DHL, and USPS. Set up and integrate any of these carriers’ service levels in a few simple steps within the Zonos™ platform. These pre-built integrations display your rates inside the Zonos Checkout within minutes.

Custom rates

Surface shipping rates for any carrier or 3PL you can imagine, or just have the custom rates you want to display at checkout. Being carrier-agnostic allows you to maintain power and control, so your cross-border solution does not need to change when your carrier does. You can upload custom rate charts, giving you complete control of which rates you show and when. Have flat-rates that you want to show per country or by weight? Zonos makes that easy to do too!

Robbi rules

Many companies have complex products and shipping rules that ecommerce platforms and shipping software just cannot handle. Robbi (Zonos’ proprietary rules engine) gives you unlimited possibilities to managing that data.

For example:

Robbi becomes your favorite over-worked, underpaid employee and ensures your complex shipping rules and calculations display correctly to your customer upon checkout. Learn more about Robbi’s computing capabilities and the creative rules other companies use to handle complex calculations, outcomes, and scenarios.

Weights and dimensions

Weight or billable weight is crucial for accurately calculating shipping costs. Weights and dimensions can be passed via the Zonos API through one of our extensions, or they can be uploaded and maintained within Zonos. Although it is preferred to have your products’ actual weight or dimensions, Zonos works with many merchants who do not have this data but are still able to estimate a highly accurate shipping quote through a variety of rules and algorithms. You can now confidently ship cross border without some of the seemingly necessary information.

Additional carrier fees

It is important to be aware of other charges that can occur in addition to your standard shipping costs. Many of these changes will not be calculated unless specific information is sent to your carrier’s API or you have the logic built into your shipping software. Standard fees include fuel surcharges, out of area fees, residential surcharge, additional handling surcharge, and oversize fees. Some of these fees may add over $100 to what would normally be a $30 shipment. Zonos shipping calculations help to ensure these fees are included, when appropriate, to make sure you are not losing money with shipping.

Examples of common additional carrier fees

Carrier Name Description Fee
UPS Over Maximum Limits Weight > 150 lbs. or Length > 108 in. or Length + Girth > 165 in. $110 / pkg.
FedEx Oversize Charge Length > 108 in. or Length + Girth > 130 in. $72.50 / pkg.
DHL eCommerce Oversize / Overweight Length > 48 in. / Weight > 150 lbs. $72.50 / pkg.
UPS Extended Area Surcharge Packages picked up or delivered in an extended area > of $30.00 / shipment or $0.30 / lb.
FedEx International Out-of-Delivery/Pickup)-Area Surcharge Packages picked up or delivered in an extended area > of $34 / shipment or $0.34 / lb.
DHL eCommerce Remote Area Service Packages picked up or delivered in a remote area > of $34 / shipment or $0.34 / lb.


The Zonos cartonization tool can be used to help determine the best box size for each order and uses that info to display the most accurate quote possible. With the necessary data, e.g. item weight, dimensions, and your box sizes, each item in an order runs through the cartonization tool to determine the most optimal box to ship that order. This gives your customers the lowest shipping quote possible and helps to capture more orders at checkout.

Shipping buffers and fees

Buffers and additional charges can be quickly added to the shipping within the Zonos platform. Increase shipping costs by a percentage, flat rate, carrier, or service level. Zonos can also add part or all our fees into the shipping cost so you can pass our fees onto the customer, allowing you to use Zonos at no additional cost to you. Note that, when purchasing from US websites, any increase in shipping costs can adversely affect your conversion.

Domestic shipping calculations

Giving domestic shipping options to international customers is highly important to your business. Many international customers will ship to freight forwarders, family, or locations close to the US border to save on shipping and other fees. Having a domestic shipping option in the Zonos Checkout allows a more seamless shopping experience while allowing you, the merchant, to use the shipping rules, possible fraud tools, and protection for your international customers. Zonos can add a default shipping service level like UPS Ground or USPS, but if you have a flat rate or free shipping set up on your domestic cart, discrepancies may cause issues and put you out of compliance with Google Adwords. We highly recommend matching your domestic shipping providers and prices to the US in the Zonos Checkout.

The United States is automatically enabled when you set up your Zonos Checkout. There are multiple reasons to let Zonos manage certain orders that ship domestically. For instance, if the IP of the individual is outside of the US, Zonos Hello will set the flag to the country they are currently located in. When the customer goes to checkout, they will be directed to the Zonos Checkout and would get blocked from completing the purchase if they did not enable the US as a shipping destination. Also, when a customer is billing to a foreign address, it may be beneficial to have Zonos Fraud Coverage help manage the additional risk, especially if you do not allow a customer to bill to an address outside the US inside of your ecommerce platform. If they are paying with a non-US credit card, they may have shopped and expected to pay in their local currency but ship to a US address. You can still decide what fits best with your business and manage country destinations inside of Zonos.

Exclusively using Zonos Checkout

Although Zonos was built specifically for cross-border and international transactions, many services and tools we provide have allowed some merchants to offer a better checkout experience for their domestic customers. Zonos has also helped these merchants manage complex shipping rules they were unable to handle with their existing shopping cart platform. If you feel like Zonos Checkout could also help with your domestic checkout experience, please contact us for custom pricing.

Zonos recommends…

  • First, customers want to know what it will cost to get your product to their doorstep at time of checkout. Having to email or wait for a quote has become a burden in today’s “I want it now” world. The ability to surface the best rate at the time of checkout, without the worry of losing money on shipping, is crucial.
  • Second, ensuring that you are not losing money or subsidizing more than expected is critical to your international success. Zonos recommends running shipping audits for the first few months to verify shipping quotes are what they should be and making any necessary adjustments early.
  • Third, flat-rate shipping is quite appealing to the international customer. When possible, offering flat-rate shipping to even your higher traffic countries will result in higher conversion and more repeat customers.