We aimed to identify the minimum number of ABP measures to accurately determine daytime and nighttime systolic BP averages and nocturnal dipping status (i.e., relative daytime:nighttime change). Forty-three midlife participants wore an ABP monitor for 24 hours with measurements every 20/30 minutes during the daytime/nighttime, as identified by a sleep diary. We calculated daytime/nighttime systolic BP average and dipping status from all available measurements per participant (i.e., normative data). We then calculated daytime and nighttime BP per participant based on a random selection of 8-20 and 4-10 measurements and replicated random selections 1000 times. We calculated accuracy by checking the proportion from 1000 different randomly selected samples for a particular number of measurements that systolic BP was ±5 mmHg of normative data, and dipping status remained unchanged for each participant compared to the normative value. The best fit for the regression model estimated the minimal number of measurements for an accuracy of 95% in BP averages. For a 95% accuracy in estimating daytime and nighttime systolic BP, 11 daytime and 8 nighttime measurements were required. The highest accuracy for dipping status was 91.6±13.4% using 20 daytime and 10 nighttime measures, while the lowest was (83.4±15.1%) using 8 daytime and 4 nighttime measures. Eleven daytime and eight nighttime measurements are likely enough to calculate average systolic BPs accurately. However, no minimum number is suggested to accurately calculate dipping status.