Do extra-large eggs take longer than large eggs?

Usually, when the starting temperature and cooking method are the same.

Is exact egg weight better than carton size?

It is a more specific input, but kitchen conditions still affect the result.

Does Egg Timer account for altitude?

No. You may need to add time and calibrate manually at higher altitude.

Does doubling the number of eggs double the time?

Do not multiply a single-egg time by the batch size. Water and cooking conditions change with a batch, and Egg Timer does not compensate for the number of eggs.

Guide

Does Egg Size Change Boiling Time?

Learn why small, medium, large, and extra-large eggs may need different boiling times and how to make a practical adjustment.

Updated October 17, 2026 2 min read

Egg Timer is free to download.

Short answer

Yes. A larger egg usually needs more time for heat to reach the centre than a smaller egg at the same starting temperature. Carton sizes are ranges, so exact weight can be a more specific input when eggs vary within the box.

The same boiling time can leave a small egg firm and a larger one softer in the centre. Size matters when the starting temperature and method are held steady. Use a size-specific estimate, then check the result before cooking a larger batch.

How to compare two egg sizes

Keep the same	Change
Starting temperature	Size or measured weight
Boiling-water start	The calculated time
Cooling method	Only the next timing adjustment

Cook one test egg at the selected time and record the result in your own kitchen notes. Compare with another size using the same starting temperature. If both size and temperature change, you won’t know which caused the difference.

What carton size tells you

Labels such as S, M, L, and XL group eggs into weight ranges. The exact ranges differ by country, and two eggs in one carton will not always weigh the same.

Use the carton size when you want a quick estimate. Enter exact weight when the eggs differ visibly or you want a more specific calculation.

The University of Exeter’s egg-heating model uses mass and starting temperature as separate inputs. That supports adjusting for size, but its idealized assumptions are another reason to test the result in your own kitchen.

Keep other variables steady

Compare eggs using the same hot-start or cold-start method. Changing the starting method changes the timing more than a small size adjustment.

Use a similar pot, water level, boil intensity, and cooling step. At high altitude, boiling water is cooler and eggs may need longer. Egg Timer does not adjust for altitude.

Calibrate without wasting a batch

Test one egg before cooking many for an event or meal prep. Cool it promptly, open it, and note whether the yolk is looser or firmer than you wanted.

Change the next attempt by a small amount. Large corrections make it harder to learn what suits your usual eggs and stove.

Set egg size or weight in Egg Timer

Egg Timer calculates a starting time from carton size or exact weight, starting temperature, and selected yolk texture. It does not measure the egg automatically.