Left ventricular outflow tract diameter (LVOTd) is essential for estimating stroke volume and aortic stenosis severity, but technical limitations may affect its accuracy. A predicted LVOTd may overcome these issues, though it has not been validated in large populations. We studied the participants of the representative random sample and with ≥ 60 y-o from the Elsa-Brasil study with echocardiogram performed (n=3,267), divided into a derivation (70%) and a validation subgroup (30%). In the derivation cohort, independent determinants of LVOTd were identified, and a regression equation was derived. In the validation cohort, the performance of LVOTELSA was evaluated and compared with previously published formulas. In our derivation sample (n= 1,822; 58.9 ± 9.5 y-o; 52% females), the mean measured LVOTd was 19.5 ± 2.5 mm. The strongest predictors of LVOTd were sex, height, aortic root diameter (AoDiam), and LV end-diastolic diameter (LVEDD), deriving the equation LVOTELSA = 0.03 + [0.59 x male] + [0.04 x height] + [0.22 x AoDiam] + [0.13 x LVEDD]. In the validation sample (n=739), LVOTELSA showed a high correlation (r=0.63) with measured LVOTd with similar agreement to LVOTPestelli (r=0.61), but worse with LVOTBSA(r=0.47). These differences are reflected in relevant differences in stroke volumes. LVOTELSA showed good performance in a general adult population and may be used as an alternative when direct echocardiographic measurement of LVOTd is not feasible.