Average Basket Size (ABS)

Date created: Dec 16, 2020  •   Last updated: Jan 10, 2022

What is Average Basket Size?

Average Basket Size (ABS) is an e-commerce metric that tracks the average number of items sold per transaction. In other words, ABS measures the increase or decrease in the quantity of items purchased per transaction. It can also be used to calculate the Average Basket Value, which is the average cost of units placed in the basket.

Alternate names: Items Per Purchase, Average Shopping Cart Size

Average Basket Size Formula

ƒ Count(Units in Transactions) / Count(Transactions)
ƒ Count(Units Sold) / Count(Invoices)

How to calculate Average Basket Size

During a particular season, a company had 4,000 transactions and sold a total of 10,000 units. Their ABS for the season is 10,000/4,000 or 2.5.

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How to visualize Average Basket Size?

Remember, ABS measures the average number of items your customers' baskets across all transactions in a given period. It is beneficial to observe trends in your ABS and other key transaction metrics. Think about what it would look like if you tracked ABS, Average Order Value, and count of Transactions in your eCommerce dashboard. Your Average Basket Size data could be represented using the following chart types:

Average Basket Size visualization examples

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Average Basket Size

Line Chart

Here's an example of how to visualize your Average Basket Size data in a line chart over time.
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Average Basket Size

4.54 Units

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0.37

vs previous period

Comparison Chart

Here's an example of how to visualize your current Average Basket Size data in comparison to a previous time period or date range.
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Average Basket Size

Line Chart

Here's an example of how to visualize your Average Basket Size data in a line chart over time.

More about Average Basket Size

Average Basket Size is an excellent support metric for Average Order Value (AOV), also known as Average Basket Value, as it can provide context behind why AOV is either increasing or decreasing.

For example, Corey’s Cyclery has historically held a relatively steady AOV of $250 and an ABS of 2.5 week over week, but as winter arrives and the clearance sales begin, AOV increases to $375. Corey and his team are thrilled with the uptick and begin to review what is driving this increase in AOV. However, in their review they discover that Transactions have remained fixed while Revenue has increased 50%. What is driving this revenue increase?

Reviewing the Average Basket Size, the team is able to see that the 50% increase in AOV was driven entirely by the number of units in customer’s baskets (i.e., +150% increase in ABS from 2.5 to 6.25 units per basket). In other words, the summer clearance encouraged customers to increase the quantity of items purchased in their baskets, but not the number of transactions made.

Continuing to track ABS and using it as a supportive metric will enable Corey’s Cyclery to quickly and easily understand these changes to AOV. Moreover, utilizing ABS in tandem with Average Selling Price (ASP) provides an even greater context to changes in AOV.

Average Basket Size Frequently Asked Questions

What is Average Basket Size in retail?

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In retail, Average Basket Size is calculated by measuring the total units sold per invoice.