This study aimed to classify fingertip defects according to dimensions and composite content, and present algorithmic reconstruction results with free lateral great-toe flaps. A total of 33 patients who underwent reconstruction for full-thickness defects of fingertips with free lateral great-toe flaps were retrospectively reviewed. Patients were divided into four groups by the algorithm according to the dimension and content of defects. Functional disabilities of the upper extremities, limitations of donor feet, finger cosmetics, sensory recovery, and pinch power were evaluated using the disabilities of the arm, shoulder and hand, foot function index, 5-point Likert satisfaction scales, Semmes-Weinstein monofilament and static 2-point discrimination tests, and pulp pinch-strength test, respectively. The standardized distribution of patients according to dimensions and content of defects was achieved. When the composite content of defects increase such as group 4, complex surgical skills are required, duration of surgery is extended, return to work is delayed, and donor-site complications are increased. Functional limitations of the hands improved normally after reconstruction (p<0.00). Sensory recovery of flaps was normal and test scores were strongly correlated (p=0.78). All patients and observers were satisfied with finger's cosmetics. Our classification and reconstruction algorithm is simple and easy to apply for all fingertip defects without complicated reference points, and it provides information about the surgical and post-surgical periods. When the dimension and composite deformities of the defect increase through groups 1-4, more complex reconstruction, increased donor-site complications, prolonged duration of surgery, and delayed return to work are observed.