Egg Boiling Time Calculator
Enter egg weight, starting temperature, and altitude to instantly calculate perfect boiling times for soft, half-boiled, medium, and hard-boiled eggs.
Input Data
Results
At a glance:Enter egg weight, starting temperature, and altitude to instantly calculate perfect boiling times for soft, half-boiled, medium, and hard-boiled eggs.
Formula
Boiling point falls as altitude rises (lower atmospheric pressure).
Cooking time comes from a heat-transfer model using egg weight, starting temperature, and water temperature.
$$P = 29.921 \left(1 - 6.8753\times10^{-6} \cdot h\right)^{5.2559}$$$$T_b = \left(49.161 \ln P + 44.932 - 32\right)\cdot\frac{5}{9}$$$$t = m^{2/3} \cdot 31 \cdot \ln\left(\frac{k(T_e - T_b)}{T_y - T_b}\right) + 10$$How to Use
- Enter the egg weight in grams.
- Enter the egg's starting temperature and your altitude.
- The calculator returns boiling times for soft, half-boiled, medium, and hard-boiled eggs.
FAQ
Why consider altitude for boiling time?
Higher altitude means lower atmospheric pressure and a lower boiling point. The smaller gap between egg temperature and boiling point slows heat transfer, so it takes longer; at very high altitude you may not reach a fully set yolk.
What is the difference between a soft egg and a jammy egg?
A soft egg has a runny yolk centre around 65°C. A jammy egg has set white but a soft yolk, between soft and medium; it cooks a bit longer than a soft egg.
Add eggs to boiling or cold water?
The calculator assumes eggs go into already-boiling water, the common method. Starting from cold water needs a different estimate.
Do larger eggs need more time?
Yes. Time scales with egg mass to the power 2/3, so bigger eggs take longer, but not linearly — larger surface area also loses heat faster.
Why plunge into cold water after?
Cold water stops conduction immediately so residual heat does not overcook the yolk, and it makes the shell easier to peel.
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.