It typically takes around 1.5 to 2 months for black hair dye to fade to a brownish hue. However, the exact timeframe can vary depending on several factors such as the quality of the dye used, the individual’s hair type, and their hair care routine. Frequent washing, heat styling, and exposure to sunlight can all contribute to color fading faster. To extend the life of your black hair dye and maintain its vibrancy, it is important to use high-quality products and follow proper hair care practices. Regular touch-ups and consultations with a professional hairstylist can also help keep your hair looking its best.