Overview

Customer Service by Amazon (CSBA) is an optional program that lets self-fulfilling sellers hand off buyer support to Amazon's customer service team. While the program is completely free for most enrolled sellers, fees can apply if your store generates an above-average volume of buyer contacts. Understanding how CSBA pricing works can help you keep costs at zero while offloading time-consuming customer interactions.

Key Points / What Sellers Need to Know

• Free for most sellers — CSBA costs nothing as long as your Contact Per Unit (CPU) rate stays at or below 3% each quarter. The vast majority of enrolled sellers never pay a fee.
• CPU is the key metric — Your Contact Per Unit percentage determines your fee tier. It is calculated by dividing the number of buyer contacts Amazon handles on your behalf by the total number of seller-fulfilled units you shipped during the quarter.
• Fees are tiered and per-unit — If your CPU exceeds 3%, you are charged a per-unit fee on every seller-fulfilled shipment the following quarter, ranging from $0.10 to $0.70 depending on how high your contact rate is.
• 90-day free trial — New CSBA enrollees receive a 90-day grace period starting from the date they ship their first self-fulfilled order, giving them time to optimize operations before any fees could kick in.
• FBA, SFP, and Multi-Channel Fulfillment are excluded — CSBA fees only apply to seller-fulfilled orders. If you use Fulfillment by Amazon, Seller Fulfilled Prime, or Multi-Channel Fulfillment, customer service is already baked into those programs.

How the Fee Calculation Works

CSBA fees are driven entirely by your Contact Per Unit (CPU) rate, which Amazon recalculates at the end of every fiscal quarter. The formula is straightforward: take the number of buyer contacts Amazon's team handled for you during the quarter and divide it by the number of seller-fulfilled units you shipped in that same period. For example, if Amazon handled 50 contacts and you shipped 1,000 units, your CPU would be 5%. That rate then determines your fee tier for the following quarter, not the current one. This look-back system gives sellers a built-in buffer and the opportunity to address issues before fees escalate.