OBJECTIVES Productivity costs often reflect a large part of the total cost in economic evaluations adopting a societal perspective. Currently, no consensus exists on how productivity losses are best measured. We aimed to develop a standardized instrument for measuring productivity losses to enhance the comparability and generalizability of the outcomes of economic evaluations.   METHODS A focus group of well-experienced researchers in the field of measuring and valuing productivity losses for use in economic evaluations assessed the instruments’ main quality criteria including: building on pre-knowledge and evidence on items’ reliability and validity, inclusion of  all relevant domains of productivity losses, allowing for quantifying productivity losses suitable for self-report. A feasibility study was performed to check on consistency and intelligibility of the questionnaire and applicability for different valuation methods. RESULTS The focus group identified three separate aspects of productivity losses leading to three modules in the iPCQ. Questions for measuring absenteeism and presenteeism are evidence- based originating from the Short-Form Health & Labour Questionnaire and PRODISQ. As evidence regarding measurement of losses of unpaid work is lacking, the questions of this module were developed during brainstorm sessions, based on similar questions on paid work. To enhance the instruments’ feasibility and responsiveness the draft version was translated into language level 1 by an agency specialized in language and clear writing. The feasibility study included 195 respondents aged > 18 years. Five percent identified problems while filling in the iPCQ, including the questionnaire’s instructions and routing (n=8) and wording (n=2). CONCLUSIONS The iPCQ is based on previously available instruments and satisfies the current scientific state of play in productivity cost measurement and valuation. The instrument is understandable for the vast majority of the general public including low-educated people. To enhance the applicability of the iPCQ for national and international studies a translation in English is performed.