Calculations based on a single-point standard linear calibration curve which has a finite intercept are a potential source of bias error. The error has been shown to be a function of magnitude of the slope and intercept, and the magnitude of the difference in the standard and sample responses. For maximum accuracy, the ratio of the difference in responses to the standard response should be the lowest possible. For any response curve, a reliable calculation of the percent error resulting from making a single-point-ratio calculation (SPRC) where a finite intercept exists is shown so that a decision as to its proper use or non-use may be made. In most cases, even when an analytically significant intercept is found in a linear calibration curve, the SPRC technique may stili be employed by calculating the sample signal to standard signal, S,/S, ratio range for an acceptable % error bias range. This calculation of the S,/S, ratio constitutes a trade-off between the use of a single standard and a shortened linear dynamic range with its possibility of more reanalyses against the use of the entire linear dynamic range with its mandatory requirement of more standards but the lesser possibility of reanalyses.