The length of a life sentence varies depending on the country and the crime committed. In many countries, including the United States, a life sentence means that the defendant is required to remain in prison for all of their natural life or until parole. However, in some countries, courts have the authority to pass prison terms that may amount to de facto life imprisonment, meaning that the sentence would last longer than the human life expectancy.

In the United States, a basic life conviction carries a minimum of 25 years before parole eligibility. However, in most states, a life sentence means that the defendant is required to live 15 years in prison before they are allowed parole. In some cases, a defendant may be sentenced to life without parole and would be in prison for the remainder of their life.

In Canada, a life sentence is the most severe punishment for any crime, and a person serving a life sentence must serve for a certain length of time before becoming eligible for parole. First-degree murder and high treason carry the longest period of parole ineligibility in the Criminal Code, at 25 years. Parole eligibility for second-degree murder typically varies between 10 and 25 years, and is set by the sentencing judge.

In the United Kingdom, a life sentence always lasts for life, whatever the length of the minimum term. However, there is one exception, which is when a judge passes a ‘whole life order’. This sentence means that the offender must spend the rest of their life in prison.

In summary, the length of a life sentence depends on the country and the crime committed. In most countries, a life sentence means that the defendant is required to remain in prison for all of their natural life or until parole. However, in some cases, a defendant may be sentenced to life without parole and would be in prison for the remainder of their life.