Calculate cooking time for soft boiled egg

This calculator implements the cooking model described at The Science of Boiling an Egg.

It estimates the boiling point of water (Twater) given altitude and sea level barometric pressure from a curve fit to ITS-68 tables over the range 80-100° making it suitable for altitudes up to 5000m max.

Tegg is the cold egg temperature, Tyolk is the desired yolk temperature. The cooking time is the time to raise the yolk boundary temperature to Tyolk when the cold egg is placed in boiling water, and the boil maintained for the cooking time, then the egg is immediately cooled to below Tyolk to stop further cooking.

Mass (g)
Tegg (°C)
Tyolk (°C)
Altitude (m)
Barometric pressure (mbar)
Twater (°C)
Cooking time (s)
Cooking time (mm:ss)


The calculator does not do a lot of error checking, if you enter nonsense, it will produce nonsense. NaN means not a number, check the input values. No result will be calculated for alt>5000.

The calculated boiling temperature Twater is within 0.2°C of ITS-68 Table 6 over the range 80-100°C, and may be useful for calibration of thermometers.



Version/b> Date Description
11.01 04/06/2015 Initial./td>

© Copyright: Owen Duffy 1995, 2021. All rights reserved. Disclaimer.