Identification of the constituents in a hydrogen/hydrogen isotope mixture of gases can be difficult with a mass spectrometer of low resolving power. However, the percentage of HT in a mixture may be accurately estimated by using equilibrium constants developed by W. M. Jones. The use of two of those constants, K$sub 2$ and K$sub 3$, is evaluated for measuring the amount of HT in a mixture. The constants were evaluated for uranium hydride bed gaseous sample analysis. Evaluation is made with both error propagation and a comparison with data obtained with a mass spectrometer of high resolution. Recommended calculation formulas are given, as are error propagation derivations. Improvements in analysis accuracy are realized by use of a series of calculation formulas rather than relying upon a single equilibrium to cover a wide range of mixtures and sampling conditions. The derived error propagation formulas may be applied generally to all equilibrated low resolution mass spectrometer analyses of hydrogen isotope mixtures, with appropriate selection of delta values. (auth)