Melanoma growth speed varies significantly depending on the type of melanoma and individual factors.

• Some melanomas can grow very quickly, becoming life-threatening in as little as 6 weeks if untreated. Nodular melanoma, in particular, is an aggressive form that grows rapidly and can penetrate deeply within a few months

• Other types, like superficial spreading melanoma and lentigo maligna melanoma, tend to grow more slowly, sometimes over months or even years before spreading significantly

• A study measuring horizontal growth rates found an average growth of about 5.3 mm² per year, with some melanomas growing faster (up to 21.6 mm² per year) and others slower or not at all. This suggests that a typical melanoma might take around 3.5 years to grow from about 0.5 cm to 1 cm in diameter, though this varies widely

In summary, melanoma growth can range from very rapid (weeks to months) to slow (years), with nodular melanoma being the fastest-growing and most dangerous type. Early detection is critical for effective treatment and better outcomes