A system and method for permitting a consumer to compare premium estimates form a plurality of insurance providers based on inputting conditions which affect the premium calculation a single time to a network such as the Internet. A user initiates a session by connecting his computer to an insurance comparison website provided by a service underwriter. The user inputs various conditions which might affect the premium for a desired insurance product. The user inputs condition data to condition input screen and sends the condition data to the service underwriter. The service underwriter converts the condition data into a form suitable for a standard interface and sends the formatted data to computers of one or more participating and user selected insurance companies or underwriters. A premium calculation engine at the computer for each insurance company calculates an estimated premium. This, and other pertinent insurance policy data, is displayed to the user.