The Art and Science of the Perfect Boiled Egg
Boiling an egg seems simple, but achieving the exact texture you desire—whether it's a runny yolk for dipping toast, a jammy center for ramen, or a firm yolk for egg salad—requires precise timing and temperature control. The internal temperature of the egg rises gradually as heat transfers through the shell and the albumen (egg white) into the yolk.
The albumen sets and becomes firm at roughly 145°F to 150°F (63°C - 65°C), while the yolk begins to set at around 150°F to 158°F (65°C - 70°C). By carefully controlling the boiling time, you can halt the cooking process precisely when the white is firm but the yolk remains liquid.
The Importance of Egg Size and Temperature
Standard cooking times are universally based on "Large" eggs (which weigh exactly 2 ounces or roughly 56-60 grams). If you use a Medium or Extra Large egg, the mass changes significantly, altering the time required for heat to penetrate to the center. Furthermore, dropping a refrigerator-cold egg into boiling water lowers the water temperature and requires more time than an egg that has been resting at room temperature.
The Formula
This calculator uses a scaling factor based on the weight of the egg relative to a standard 60g large egg. It assumes you are lowering cold eggs directly from the refrigerator into water that is already at a rolling boil, and immediately transferring them to an ice bath afterward.
Adjusted Time = Base Time * (Actual Weight / Standard Weight)
The Ice Bath is Mandatory
The cooking process does not stop the moment you pull the egg out of the boiling water. The residual heat trapped inside the egg will continue to cook the yolk for several minutes (carryover cooking). To achieve a perfect soft or medium boil, you must immediately plunge the eggs into a bowl of heavily iced water for at least 5 minutes to rapidly halt the cooking process and shrink the egg slightly inside the shell, making peeling significantly easier.