Add eggs straight from fridge, in a single layer, to a saucepan. Add enough cold water to cover them by 1 inch at least. Slowly bring water to just under a boil. Once water is at just under a boil, begin to time them. Count 8 minutes for a hard boiled eggs where yolks are firm but center is still tender or 10 minutes for a fully firm inside yolk. For larger eggs, add a minute, for smaller eggs subtract a minute.
When done, remove with a slotted spoon and plunge in cold water to stop cooking process. Cool them so they are easy to handle; it is best to peel eggs just before using them. Whole boiled eggs can be kept in fridge for a week.