Objectives To determine the effect of using the NHS Choices website on primary care consultations in England and Wales. We examined the hypothesis that using NHS Choices may reduce the frequency of primary care consultations among young, healthy users. Design Two cross-sectional surveys of NHS Choices users. Setting Survey of NHS Choices users using an online pop-up questionnaire on the NHS Choices website and a snapshot survey of patients in six general practices in London. Participants NHS Choices website users and general practice patients. Main outcome measures For both surveys, we measured the proportion of people using NHS Choices when considering whether to consult their GP practice and on subsequent frequency of primary care consultations. Results Around 59% (n = 1559) of online and 8% (n = 125) of general practice survey respondents reported using NHS Choices in relation to their use of primary care services. Among these, 33% (n = 515) of online and 18% (n = 23) of general practice respondents reported reduced primary care consultations as a result of using NHS Choices. We estimated the equivalent capacity savings in primary care from reduced consultations as a result of using NHS Choices to be approximately £94 million per year. Conclusions NHS Choices has been shown to alter healthcare-seeking behaviour, attitudes and knowledge among its users. Using NHS Choices results in reduced demand for primary care consultations among young, healthy users for whom reduced health service use is likely to be appropriate. Reducing potentially avoidable consultations can result in considerable capacity savings in UK primary care.