It’s common to see differences in shipping rates between the cart and checkout pages. Here’s why that happens:

Location Accuracy

While the customer is on the cart page, their exact location isn’t fully known. The system detects their location using IP geolocation, which is generally accurate at the state level and fairly accurate at the city level, but it doesn’t pinpoint the zip/postal code.

Location Details

On the checkout page, the destination includes the full shipping address: country, state (if applicable), city, zip/postal code (if applicable), and one or two address lines. However, on the cart page, by default, only the country, state, and zip/postal code are considered. You can optionally enable fields for the city and address to be included in the Cart Summary and/or Expandable Calculator widgets by adjusting the app’s settings. While the city can sometimes be detected via IP geolocation, the address will only be used for cart shipping rates if the customer manually enters it in the widget before requesting the rates.
At checkout, the customer provides their actual shipping address, and the shipping rates are recalculated accordingly. If the destination used in the cart differs from the one entered at checkout, this can lead to differences in the shipping rates shown and the amounts calculated.