Inches of water to atmospheres (technical) converter on this page calculates how many atmospheres (technical) are in 'X' inches of water (where 'X' is the number of inches of water to convert to atmospheres (technical)). In order to convert a value from inches of water to atmospheres (technical) (from inH2O to at) just type the number of inH2O to be converted to at and then click on the 'convert' button.