The correlation proposed in this work has been compared statistically with a larger database of bio-oils taken from values in the literature. The correlation developed here uses only one formula used in the major constituents of elementary analyses. Seventy-nine data points have been used to derive this correlation. This correlation is valid for bio-oils having a broad range of elemental composition, that is C: 8.2-89.3%; H: 4.6-14.4%; O: 1.4-76.9%; N: 0.0-10.8%; and S: 0.0-1.8%. It presents an average absolute error of 1.21% and bias error of 0.59%, and thereby establishes its versatility.