Sources and method
Base times
For a 58 g egg (US Large) lowered into boiling water: soft 5 min (fridge) or 4 min (room temperature), jammy 6:30 or 5:30, hard 10 or 9 min, from tests by Serious Eats (J. Kenji López-Alt) and America's Test Kitchen. Poached 3 min, baked 11 min in a water bath at 180 °C (350 °F).
Egg size
Heat reaches the yolk in a time proportional to mass to the power 2/3 (Charles Williams' formula, University of Exeter): the base time is multiplied by (weight / 58 g)^(2/3) and rounded to 15 seconds. US sizes (USDA, minimum weight per egg): Medium 49.6 g, Large 56.7 g, Extra large 63.8 g, Jumbo 70.9 g.
Corrections
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