Gills (US) to gallons (US liquid) conversion calculator above calculates how many gallons (US liquid) are in 'X' gills (US) (where 'X' is the number of gills (US) to convert to gallons (US liquid)). In order to convert a value from gills (US) to gallons (US liquid) type the number of gills (US) to be converted to gal and then click on the 'convert' button.