This calculator was developed by Prof. Jarek Kurnitski and the REHVA COVID-19 Task Force for specialists with at least a minimum understanding of ventilation and air distribution. The tool is available for download for experts who have read and understood the related COVID-19 guidance document, as well as the explanation on the use of the tool or are enrolled in the REHVA COVID-19 course. The tool was developed before the detection of the latest, more contagious SARS-CoV-2 variants (in the UK, South-Africa etc.), and any subsequent research on the topic has not been considered for its development and update. Therefore, its application and calculation results should be interpreted considering this limitation. To download the xls calculator, please fill in the form below and accept the terms and conditions.