Abstract: An improved gas flow meter which measures the time of travel of a soap film through a fixed volume to compute gas flow rate. A portable meter includes infrared sensors which detect the passing of a soap film, a timing circuit to determine the time of travel between the beginning and end of the fixed volume and a method of blocking the infrared portion of ambient light to allow for use outdoors. The device has a unique method of generating the soap bubble and for breaking the soap bubble at the end of the fixed volume. The unique flow unit, including flow cell and fixed sensors, is calibrated to determine the fixed volume which is stored in a nonvolatile memory location as a part of the flow unit.