To choose the right size range hood for your stove, you should measure the width of your cooktop and choose a hood that is at least as wide as the cooktop, or slightly wider. The recommended airflow rate for a range hood is measured in cubic feet per minute (CFM), and it should be able to exchange the air in the kitchen at least 15 times per hour. The height of the hood should also be considered to ensure it is at the appropriate distance from the cooktop to effectively capture smoke and grease. It is recommended to consult a professional or refer to the manufacturer's guidelines to ensure proper installation and sizing of the range hood.