Achievement of steady state during indirect calorimetry measurements of resting energy expenditure (REE) is necessary to reduce error and assure accuracy in the measurement. Steady state is often defined as five consecutive minutes (5-min SS) during which oxygen consumption and carbon dioxide production vary by ± 10%. These criteria however are stringent and often difficult to satisfy. This study aimed to assess whether reducing the time period for steady state (4-min SS or 3-min SS) produced measurements of REE that were significantly different from 5-min SS. REE was measured using open circuit indirect calorimetry in 39 subjects, of whom only 21 (54%) met the 5-min SS criteria. In these 21 subjects, median biases in REE between 5-min SS and 4-min SS and 5-min SS and 3-min SS were 0.1% and 0.01%, respectively. For individuals 4-min SS measured REE within a clinically acceptable range of ± 2% of 5-min SS, while 3-min SS measured REE within a range of -2 to 3% of 5-min SS. Harris-Benedict prediction equations estimated REE for individuals within ± 20 to 30% of 5-min SS. Reducing the time period of steady state to four minutes produced measurements of REE for individuals that were within clinically acceptable, predetermined limits. The limits of agreement for 3-min SS fell outside the predefined limits of ± 2%, however both 4-min SS and 3-min SS criteria greatly increased the proportion of subjects who satisfied steady state, within smaller limits than would be achieved if relying on prediction equations.