Where these cooking time estimates come from
Professional kitchens and cookery references commonly express roasting and boiling times as a rate per kilogram plus a fixed base time, rather than a single flat number, because a 3kg roast doesn't simply take three times as long as a 1kg one — heat needs proportionally less extra time to penetrate a larger mass once a base cooking time is accounted for. This calculator uses that same per-kilogram-plus-base approach for each food type, giving a more realistic estimate than a flat multiplier would.
These are reference estimates based on commonly published home-cooking rates, not a substitute for checking actual doneness, particularly for meat and poultry where food safety depends on reaching a safe internal temperature, not just elapsed time.
Why a food thermometer still matters
Oven calibration, starting temperature of the food (fridge-cold versus room temperature), pan material and even altitude all shift real cooking time away from any published estimate, sometimes by 15 minutes or more on a large roast. For meat and poultry specifically, using a food thermometer to confirm the internal temperature has reached a safe level is the only reliable way to know a dish is properly cooked, regardless of what the timer says.
This calculator's estimate is best used as a planning guide — for deciding when to start cooking relative to a mealtime — rather than as the final word on doneness.
Boiling versus roasting times for the same food
Boiling generally cooks food faster than roasting for the same item, because water conducts heat into food far more efficiently than the dry air of an oven, which is reflected in the different per-kilogram rates this tool uses for each method. Not every food is commonly cooked both ways — turkey, for example, is essentially always roasted rather than boiled, which is why this tool marks boiling as 'not typical' for foods that aren't usually prepared that way.
Frequently Asked Questions
Is this safe to rely on for cooking chicken and meat?
Use it as a starting estimate only — always confirm meat and poultry have reached a safe internal temperature with a food thermometer before serving, since actual cooking time varies by oven and starting temperature.
Why does the estimate change so much between roasting and boiling?
Water conducts heat much faster than air, so boiling times are generally shorter than roasting times for the same food and weight.
Does this account for stuffed or bone-in versus boneless items?
Not specifically — stuffed or bone-in items typically need extra time beyond this estimate, so add a safety margin and check doneness carefully for those.
What if my food isn't in the list?
Choose the closest comparable food by density and size — for example, a similar root vegetable to potatoes — as a rough starting estimate.