Embodiments of the invention provide systems and methods for automatic or adaptive sizing of a customer service agent's co-browsing view of a contact's user interface. According to one embodiment, at least a portion of the agent's interface in which the customers interface is presented can be resized so that the agent's view matches the customer's view, e.g., one-to-one. This sizing of the agent's view may be performed automatically, when the co-browsing view of the customer's interface is first presented to the agent or, according to one embodiment, may be toggled on and off by the agent, e.g., by the agent selecting a button or other control presented in the agent's interface. In this way, embodiments allow the agent to see exactly the same view of the web site as the customer sees in the customer's interface regardless of the device or screen size used by the customer.