This study assessed the in vitro accuracy, precision, specificity, and measurement uncertainty of BACtrack®'s line of smartphone-connected breath alcohol analyzers. At the 0.080 g/210L ethanol vapor concentration the measurement uncertainty was determined to be ± 0.013, 0.004, and 0.006 g/210L for the Pro, C8, and C6 respectively at the 95% coverage interval. The analyzers showed an apparent ethanol response to isopropanol, and methanol, but not to acetone. BACtrack®'s smartphone-connected breath alcohol analyzers showed the ability to measure vaporous ethanol with confidence in the results.