# What is the Half-life of Potassium 40

Potassium-40 which is a radioactive isotope of potassium usually has two half-lives which are mainly based on what type of beta decay that it undergoes. If Potassium-40 decays through beta emission then its half-life will be 1.28 × 109 years. On the other hand, if potassium-40 decays through positron emission the half-life will be 1.19 × 1010 years.