The time it takes for a grade 3 thyroid nodule to become a grade 4 is not yet definitive and varies from person to person. Thyroid nodules are hyperplastic lesions caused by abnormal localized growth of the thyroid gland, including nodular goiter, thyroid adenoma, and thyroid cyst. In ultrasound examination of the thyroid gland, thyroid nodules are categorized into 6 grades, and the higher the grade, the higher the risk of thyroid cancer. Thyroid nodules graded at grade 3 or below have a higher probability of being benign nodules, grade 4 or above may be malignant, and grade 6 can be determined to be malignant. The speed of malignancy varies from person to person and is related to the patient’s genes, living condition, psychological state, etc. There is no definite time. Thyroid nodule grade 3 may be benign nodule, the malignant rate is not high, some people may not develop into grade 4. Patients are advised to relax, avoid too much tension or anxiety, have a regular routine, and seek timely medical attention for targeted treatment under the guidance of a doctor.