Electrical cardiometry (EC) is a non-invasive cardiac output method that can assess cardiac index (CI) and stroke index (SI) but there are no reference values for children per se. The primary aim of this study was to develop reference values for clinical application. The secondary aim was to compare the EC measurements to published values. We performed a prospective observational study in patients (<21 years of age) without structural heart disease who had recovered from an acute illness. EC recordings in children that had normal heart rate and mean arterial blood pressure at discharge were eligible for analysis. The relationship of CI or SI and age in children was performed by regression analysis. Similar analysis was performed comparing measurements by EC to cardiac parameters values compiled from reference sources to assess bias in EC. Eighty-three children (2 weeks-21 years of age) were studied. There was a significant curvilinear relationship between CI or SI and age by EC (F-test, p < 0.05). Regression curves of cardiac parameters reported in the literature using 6 Fick's method, thermodilution, echocardiography and cardiac MRI were the same or higher than (0-19.6 %) values obtained with EC, with higher values being statistically significant (p < 0.05 all). There is a curvilinear relationship of CI or SI and age by EC in normal children. Cardiac parameters reported in the literature using alternative methods are different from those obtained with EC but are within acceptable ranges, with EC biased to underestimate CI. Adjustment of target value is required for EC goal-directed therapies.