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Recipe scaling calculator

Updated
Quick answer

Ingredient quantities scale linearly with servings, so doubling from 4 to 8 multiplies every quantity by 2. Cooking time does not scale: it follows thickness and the appliance, so a doubled sous vide batch takes exactly as long unless the pieces got thicker.

Your numbers

Result

Scaling factor
1.5 x
Your ingredient becomes
750
Cooking time
Unchanged
Oven or bath temperature
Unchanged
Pan area needed
1.5 x the original area

Time does not scale with quantity. In a water bath it follows thickness alone, so a doubled batch of the same steaks takes the same time. In a pressure cooker the time at pressure is unchanged but the come-up grows. In an oven a larger tray needs more space between pieces or it steams instead of browning. Pan size scales by area: a pan twice the area is only about 1.4 times as long on each side.

The formula

factor = target servings / original servings new quantity = original quantity x factor What does NOT scale: cooking time follows thickness and appliance oven temperature unchanged salt in a brine already a percentage pan size scales by area, not by length

The most expensive scaling mistake is assuming time scales with quantity. Doubling a pressure cooker recipe does not double the time at pressure, though it does lengthen the come-up. Doubling a sous vide bag changes nothing at all unless the pieces are thicker.

Gear that fits these numbers

Scaling is a weighing problem

Scaled volume measures compound their own error. A 1.5 times cup measurement is an estimate of an estimate, where a scale just multiplies a number.

Prices when last checked. They change often.

What scales and what does not

Ingredients scale. Salt in a brine is already a percentage, so it scales automatically when the water does. Seasoning to taste scales sub-linearly in practice, and most cooks find that doubling a recipe wants somewhat less than double the chilli and the strong aromatics.

Time is the one that catches people. Cooking time is set by the thickness of the thing being cooked and by how fast the appliance delivers heat, not by how many of them there are. Two steaks in a bath take exactly as long as one. A doubled braise in a pressure cooker holds at pressure for the same number of minutes, though it takes longer to get there and longer to release.

Pan sizes scale by area

A recipe that doubles needs twice the surface area, not twice the diameter. A 9 inch round pan has about 64 square inches of base; doubling that needs roughly 12.7 inches, not 18. Getting this wrong is why a doubled cake batter overflows a pan that looked generous.

Frequently asked questions

Does doubling a recipe double the cooking time?

No. Cooking time is governed by the thickness of what is being cooked and by how quickly the appliance delivers heat, not by the total quantity. Two steaks of the same thickness in a water bath take exactly as long as one. What does grow is any phase where the appliance has to heat a larger mass, such as coming up to pressure.

How do I scale salt when I double a recipe?

If the recipe expresses salt as a percentage, as brines and ferments do, it scales automatically when the other weights do. If it gives a fixed amount, scale it linearly but taste before committing, since perceived saltiness does not track quantity as neatly as the arithmetic suggests, particularly in dishes that reduce.

What pan size do I need for a doubled recipe?

One with twice the base area, which is not twice the diameter. A 9 inch round pan has roughly 64 square inches; doubling that needs about 12.7 inches across, not 18. For rectangular pans, multiply both dimensions by about 1.41. Using a pan that is too small is the usual cause of a doubled batter overflowing.

Can I scale a sous vide recipe?

Freely, as long as the pieces stay the same thickness and the bath can circulate around all of them. Adding more bags does not change the time. What does matter is water volume and spacing: a crowded bath has cold spots, and a rack that keeps the bags separated is the fix rather than a longer cook.

Why does a halved recipe often taste different?

Surface area to volume changes. A smaller batch in the same pan has proportionally more surface exposed, so it reduces faster and browns more, which concentrates flavour and can push seasoning past where you wanted it. Use a smaller pan when halving, and check for doneness earlier than the original time suggests.

How this calculator works: it applies the formula above to the numbers you enter. Where a figure is published by the USDA or FSIS we quote it and name the source. Where a figure is derived from a physical model we say so and state the assumptions. Where we have no defensible figure the calculator returns nothing and tells you why, rather than guessing. This is researched general information, not professional food safety advice.