Aim: to assess the outcomes of a novel algorithm for the calculation of the amount levator muscle plication in congenital blepharoptosis surgery. Methods this retrospective comparative study included 34 patients with congenital ptosis subjected to levator muscle plication surgery during the period from October 2021 to November 2022. They were divided into two groups. Group A: the amount of levator muscle plication was calculated by a traditional formula [(amount of ptosis x 3) + 9 mm in cases with good levator function or (amount of ptosis x 3) + 11 mm in cases with fair levator function]. Group B: the amount of levator muscle plication was calculated by a novel nomogram [the result of the traditional formula was modified by subtracting 4 mm if the calculated amount was ≥ 15 mm or subtracting 3 mm if the calculated amount was < 15 mm]. Demographic data, baseline ptosis characteristics and postoperative results at 1st week, 1st month, 3rd month and 6th month were compared between the groups. Primary outcome measure was postoperative Marginal Reflex Distance (MRD1). Secondary outcome measures were lid contour, lid crease and any reported complications. Results Group A included 20 eyes of 18 patients while Group B included 20 eyes of 16 patients. The mean amount of levator muscle plication was 16.98 ± 2.44 mm and 13.48 ± 2.42 mm in group A and group B respectively. The difference between the two groups was highly statistically significant (p < 0.001). Mean MRD1 at the 1st postoperative week was 4.95 ± 0.37 mm in group A and 4.08 ± 0.64 mm in group B. This difference was highly statistically significant (P < 0.001). Overcorrection was seen in 8 (40%) eyes in group A and 1 (5%) eye in group B. The difference was statistically significant between the two groups (p = 0.008). Undercorrection was seen in only 1 (5%) eye in group B. No other complications were reported. Surgical success was achieved in 12 (60%) eyes in group A versus 18 (90%) eyes in group B. The difference between the two groups was statistically significant (p = 0.03). Conclusion: our novel nomogram for the calculation of the amount levator muscle plication in congenital blepharoptosis surgery is effective in achieving a satisfactory postoperative MRD1.