In short
Basket size is a retail metric that describes how much value, or how many items, sit in a traveller's cart or order. In travel, it helps commercial teams understand whether merchandising is creating a single add-on, a wider bundle, or a deeper order.
What basket size measures
Basket size can be measured as value, item count, or both. A travel seller may want to know how much ancillary value joined the order, or how many paid options were selected.
The definition matters. An order with one high-value item and an order with several smaller items can tell different commercial stories even if both look successful at first glance.
Why it is not attach rate
Attach rate asks whether an extra item joined the booking. Basket size asks how large the cart became once items were added.
Both metrics are useful. Attach rate shows breadth of adoption. Basket size shows depth of purchase. A strong retail flow may improve one without improving the other, so teams need to read them together.
How to improve it responsibly
Basket size grows when offers fit the trip and the traveller understands the value. It can also grow for the wrong reason if items are bundled confusingly or presented with poor consent.
Healthy basket growth comes from relevance, clarity, and timing rather than from forcing more decisions into checkout.
It also depends on measurement discipline. Teams should know whether they are counting items, value, or both before comparing journeys or channels.
Frequently asked questions
What is basket size?
It is the value or item count of a cart or order at the point of purchase.
How is basket size different from attach rate?
Attach rate asks whether an extra item was added, while basket size asks how much value or how many items were in the cart.
Why does basket size matter?
It helps teams understand whether merchandising is creating deeper, more valuable orders.