Purpose to correlate the value of slow vital capacity (SVC) with the maximum phonation time (TMF) in order to estimate the vital capacity. Methods the study is a cross-sectional crossover and participated in this research one hundred one (101) healthy subjects 71 women and 30 men. The slow vital capacity (SVC) was measured using a spirometer and TMF was evaluated by vowel “a”;, the phoneme “s”; and “z”; and the manner of counting numbers. Results there was significant correlation between the SVC (ml) and TMF (a, s, z) and technique of counting with r * respectively (0.420, 0.442, 0.399, 0.279) with a p-value <0.05 in total population. There was a positive correlation between the slow vital capacity and the variables /a /, /s /, /z / and technique of counting for females, according to values of r * (0.296, 0.334, 0.326, 0.320) respectively and p-value < 0.05 . Conclusion in this study was possible to observe a positive correlation between the SVC and TMF in total population and females, this correlation was not observed among males.