Egg Timer for Soft, Jammy and Hard-Boiled Eggs

Most guides make a single claim that causes more failed eggs than any other: that one set of times works for everyone, regardless of egg size, starting temperature, or altitude. An egg timer that ignores these three variables cannot give you consistent results. The calculator adjusts for all three and adds a fourth, altitude, because at 5,000 ft water boils at 202 °F, not 212 °F, and a sea-level chart will undercook every egg by at least one minute. You get the exact minutes for your egg, your kitchen, and your yolk preference, right now.

For a large egg (57 g), lowered into boiling water, at sea level, at room temperature:

• Soft-boiled (runny yolk, set white): 6 minutes. The yolk stays liquid and warm, ideal for dipping toast soldiers or topping a bowl of noodles.
• Medium-boiled (jammy yolk): 7 minutes. The yolk thickens to a spreadable, custard-like consistency, perfect for ramen eggs or salads.
• Hard-boiled (fully set yolk and white): 10 minutes. The yolk is firm and crumbly, the white is solid, suitable for egg salad, deviled eggs, or snacking.

These times come from the Serious Eats / J. Kenji Lopez-Alt boiled-egg timing and time-lapse tests published in 2015, which are the most widely sourced, repeatable set of times available. The calculator uses these same base values, then adds adjustments for egg size, starting temperature, and altitude.

The calculator presets assume a single large egg (USDA Large, 57 g) at room temperature, lowered gently into water that is already at a rolling boil, at sea level. This is the most repeatable method because the starting temperature of the water is fixed at 212 °F, and the egg begins cooking the second it enters the pot. A cold start (eggs in cold water, brought to a boil together) makes timing less precise because the water takes 3-5 minutes to reach boiling, and the egg cooks during that ramp-up at an unknown rate. The boiling-start method is the standard used by Harold McGee in On Food and Cooking and by the American Egg Board for hard-cooked eggs, and it is what this timer assumes for its base values.

When you select a different egg size, the calculator uses a preset base time from the USDA egg size grades (small: 43 g, medium: 50 g, large: 57 g, extra large: 64 g, jumbo: 71 g). Each step up in size adds roughly 30-45 seconds to the base time for the same doneness. A jumbo egg soft-boiled at sea level requires about 7 minutes, not 6.

Four variables shift the total cooking time. Ignore any one and your yolk will be wrong.

Egg Size

A small egg (43 g) cooks about 30 seconds faster than a large egg for the same doneness. A jumbo egg (71 g) needs about 30 seconds more. The calculator uses the USDA weight classes to adjust the base time. Do not mix sizes in the same pot unless you remove each one at its own timer mark.

Starting Temperature

Eggs straight from the refrigerator (40 °F) start colder than room-temperature eggs (about 70 °F). The cold mass takes extra time to reach the protein-setting temperatures (white sets at 144-162 °F, yolk at 158-170 °F per McGee). The calculator adds 1 minute 30 seconds for fridge-cold eggs. If your eggs are from a cold pantry or have sat out for an hour, use the room-temperature setting.

Altitude

Water boils at a lower temperature as elevation increases: approximately 1 °F drop per 500 ft gain (NIST). At 5,000 ft water boils at 202 °F, meaning the egg cooks more slowly. The Colorado State University Extension guidance recommends adding 1 minute at 5,000 ft, 2 minutes at 7,500 ft, and 3 minutes at 10,000 ft for hard-cooked eggs. The USDA FSIS High Altitude Cooking fact sheet suggests 1-2 minutes at 5,000 ft, 2-3 minutes at 7,500 ft, and 3-4 minutes at 10,000 ft. This calculator uses a mid-range adjustment: 1 minute for medium altitude (1,000-5,000 ft) and 2 minutes 30 seconds for high altitude (5,000+ ft). If you live above 7,500 ft, start with the high-altitude preset and test your next batch by adding 30 seconds more if the yolk is not set enough.

How Many Eggs

Dropping several cold eggs into a small pot of boiling water can drop the water temperature enough to add 30-60 seconds of cooking time. If you are boiling more than four large eggs in a 2-quart pot, use a larger pot (4 quarts) to maintain the boil, or add 30 seconds to the timer. The calculator does not adjust for batch size; add that time yourself.

Each method has a trade-off between precision and peelability.

Boiling-Water Start (Hot Start)

Lowering eggs into already-boiling water gives the most consistent doneness because the cooking time starts at a fixed temperature. The Serious Eats peeling tests from 2015 found this method yields about 50-70% clean peels (shells that come off without tearing the white). The egg white sets quickly against the hot shell, which can make peeling harder. Use this method when precision matters more than ease of peeling, such as for ramen eggs or any dish where yolk doneness is critical.

Cold-Water Start (Cold Start)

Placing eggs in a pot of cold water and bringing it to a boil together produces 90%+ clean peels, per the same Serious Eats tests. The downside is that the cooking time is less precise because the water heats up over 3-5 minutes, and the egg starts cooking at an unknown rate during that ramp. If you use this method, add 1 minute to the boiling-start times as a starting point, then adjust future batches. This method is better for hard-cooked eggs destined for egg salad or deviled eggs where peelability is more important than exact yolk doneness.

Steaming

Steaming eggs in a steamer basket over boiling water is a third option that avoids direct contact with the water. It produces very consistent doneness (similar to boiling-start) and can improve peelability slightly, but the times are about 30 seconds longer than the boiling-start times because steam transfers heat a little less efficiently than liquid water. The American Egg Board recommends the cold-start method for hard-cooked eggs; they do not endorse steaming as a standard method. If you steam, use the boiling-start times plus 30 seconds.

As soon as the timer goes off, lift the eggs out with a slotted spoon and plunge them into a bowl of ice water. This stops the cooking instantly, preventing the residual heat in the egg from continuing to set the yolk (which would turn a medium-boiled egg hard). It also prevents the green ring of iron sulfide from forming between the yolk and white, which occurs when eggs are left in hot water or cooled slowly. McGee explains that iron from the yolk reacts with sulfur from the white at prolonged high temperatures; immediate cold shock stops the reaction.

Let the eggs sit in the ice bath for at least 5 minutes. Longer is fine, you can leave them for up to 30 minutes without affecting texture. For hard-boiled eggs, this cooling period also helps the shell membrane contract away from the white, improving peelability. After the ice bath, dry the eggs and refrigerate them in the shell if not using immediately. Hard-cooked eggs in the shell keep for up to 1 week in the refrigerator (USDA FSIS). Peeled hard-cooked eggs should be used within 1 week as well, but keep them in a covered container with a damp paper towel to prevent drying.

The most common failure is using the same time for all egg sizes. A small egg soft-boiled in 6 minutes will be overdone; a jumbo egg soft-boiled in 6 minutes will be underdone. Always select the correct size in the timer.

The second mistake is ignoring altitude. At 5,000 ft, a sea-level chart undercooks eggs by at least 1 minute. Use the altitude adjustment in the timer, and if your eggs come out undercooked at the high setting, add another 30 seconds next time.

The third is using very fresh eggs and wondering why they won't peel. Egg age directly affects peelability: eggs 7-10 days old have a higher albumen pH (about 9.0-9.5 vs. 7.6-7.9 for fresh eggs), which reduces adhesion between the white and the shell membrane. Buy your eggs a week before you plan to boil them for best peeling. If you must boil fresh eggs, use the cold-start method for a better chance at clean peeling.

The egg timer assumes a single large egg (57 g), at room temperature, lowered into an adequate volume of water that is already at a rolling boil, at sea level. It does not assume a cold-water start, a crowded pot, or a steamer. It uses the base times from Serious Eats / J. Kenji Lopez-Alt (2015) for the three doneness levels, and the altitude adjustments are a composite of Colorado State University Extension and USDA FSIS guidance. The calculator adds 1 minute 30 seconds for fridge-cold eggs and 2 minutes 30 seconds for high altitude (5,000+ ft). If your egg size, starting temperature, altitude, or method differs from these assumptions, you must adjust the time manually or select the correct settings in the timer.

The most vulnerable point in the entire process is the ice bath. Skip it or delay it by more than 30 seconds and the egg continues to cook, turning your jammy yolk hard and your hard-boiled yolk green-rimmed. Plunge the egg into ice water the second the timer ends, before you check your phone, before you dry your hands. That is the single action that separates a perfect egg from a ruined one.