How much of bottled lemon juice is equal to 1 lemon?

Could you please clarify for me, how much bottled lemon juice would be equivalent to the juice extracted from a single fresh lemon? I'm curious to know if there's a standard measurement or if it varies depending on the brand or type of lemon juice. Understanding this ratio could be useful for recipe adjustments and ensuring I'm getting the same level of flavor and acidity in my dishes.