Life insurance companies use a process called "underwriting" to determine the premium for a life insurance policy. Underwriting is the process of assessing a potential customer's risk of death, and determining the cost of the life insurance policy based on that risk.
There are many factors that life insurance companies take into account when underwriting a policy, including the applicant's age, health, smoking status, occupation, and lifestyle. The company will also look at the applicant's family medical history, as well as any pre-existing medical conditions.
Based on all of this information, the life insurance company will give the applicant a rating, which will determine the price of the policy. The higher the risk, the higher the premium will be.
It's important to note that life insurance companies use different formulas to calculate premiums, so it's best to shop around and compare rates from different companies before purchasing a policy.