Egg Boil Calculator

How Egg Boiling Time Works

Boiling eggs is a controlled heat transfer problem. The egg white sets around 144–149°F (62–65°C), while the yolk thickens closer to 158–170°F (70–77°C). A soft-boiled egg holds a creamy yolk, a jammy egg is partially set but still spreadable, and a hard-boiled egg fully firms the yolk. By choosing doneness and adjusting for egg size and starting temperature, you can aim for the texture you want.

This calculator assumes you start with a pot of boiling water and carefully lower eggs in. Cold eggs require extra time because the shell and interior are cooler. Large eggs also take longer to heat through than small eggs. Altitude affects boiling temperature: at higher elevations, water boils at a lower temperature, which slows the cooking process. The tool adds time for altitude to keep results consistent.

An ice bath after cooking stops the heat from carrying over and overcooking the yolk. It also makes peeling easier by contracting the egg white away from the shell. For jammy or soft eggs, the ice bath is essential; for hard-boiled eggs, it prevents the green ring that can form when the yolk overheats.

Use this timing as your baseline, then adjust by 15–30 seconds based on your stove, pot size, and how gently the water boils. Once you find your ideal timing, keep it consistent for repeatable results. That is the heart of reliable egg cooking: small, measurable steps and a quick chill at the end.

When boiling multiple eggs, keep the pot size proportional to avoid temperature drops. A larger pot maintains a steady boil, while a small pot can lose heat and extend cook time. If you add a full batch, wait for the water to return to a gentle boil before starting the timer. These small controls make the difference between a creamy yolk and an overcooked center.

Formula

Base time: soft 6 min, jammy 7.5 min, hard 10 min (medium egg at sea level).

Size adjustment: small −0.5 min, large +0.5 min, extra large +1 min.

Starting temp adjustment: fridge +1 min.

Altitude adjustment: add 0.5 min per 1,000 ft above sea level.

Example Calculation

Large egg, jammy yolk, fridge cold, elevation 5,000 ft. Base 7.5 min + 0.5 min (large) + 1 min (fridge) + 2.5 min (altitude) = 11.5 minutes. The calculator returns 11.5 minutes with a 5-minute ice bath.

FAQs

Should I pierce the shell?

It is optional. A gentle simmer and steady temperature are more important than piercing.

How long should the ice bath be?

About 5 minutes is enough to stop cooking and ease peeling.

Why do my eggs crack?

Temperature shock causes cracks; lower eggs gently and avoid a rolling boil.

Is this calculator private?

Yes. All calculations run locally in your browser.

How it works

This calculator adds size, temperature, and altitude adjustments to a base boil time, then recommends an ice bath. All computation is client-side for privacy.

Food Safety Disclaimer

Times are estimates. Always ensure eggs are cooked to your preferred safety standard, especially for vulnerable populations.