It takes between 3 1/2 and 10 minutes to boil an egg. The time it takes depends on the egg's size and how firm the person wants the egg to be.
For making a soft-boiled egg that is of medium size, it takes around 3 1/2 minutes if gently boiling water is used. If the egg is large, it takes around 4 minutes. A perfectly made soft-boiled egg will have runny yolk with white that is just set. For making a medium-boiled egg with a slightly firm yolk and firm white, boil the egg for another one minute irrespective of its size. To make a hard-boiled egg with firm yolk and white, it takes around 7 to 10 minutes. The longer the egg is boiled, the firmer it will be.