Slow Cooker Conversion Calculator

How the conversion works

Slow cooker times are not worked out with a formula. They come from bands: a range of conventional cooking times is matched to a range of slow cooker hours. The calculator uses the three bands published by Penn State Extension.

• 15 to 30 minutes in the oven or on the stove: 4 to 6 hours on low, or 1 1/2 to 2 hours on high
• 35 to 45 minutes: 6 to 10 hours on low, or 3 to 4 hours on high
• 50 minutes to 3 hours: 8 to 16 hours on low, or 4 to 6 hours on high

Enter the cooking time from your recipe and the calculator shows the band it falls in. The source leaves small gaps between bands, such as 31 to 34 minutes. Times in a gap are given the nearer band.

The ranges are wide because slow cookers differ, and so do the size and cut of what goes in them. Treat the lower end as the first time to check.

Worked example

A chicken and vegetable braise cooks for 45 minutes on the stove and uses 3 cups of stock.

1. 45 minutes falls in the middle band: 6 to 10 hours on low, or 3 to 4 hours on high.
2. Liquid: reduce 3 cups by a third to a half, giving 1 1/2 to 2 cups.
3. Start it on low in the morning, and check at about 6 hours.

A pot roast that braises in the oven for 2 1/2 hours falls in the last band: 8 to 16 hours on low, or 4 to 6 on high.

Cut the liquid

On the stove, steam escapes and sauces reduce. In a slow cooker the lid stays on and almost nothing boils away. If you use the full amount of liquid from a stovetop recipe, you get a thin, watery result.

Penn State Extension’s guidance is to reduce liquids by one third to one half. Enter the liquid from your recipe in the second box and the calculator shows the range.

Soup is the exception. You want the liquid, so keep it as written.

What to add later

Not everything can sit in a slow cooker for eight hours. The same source gives two timing rules:

• Milk, cheese and cream: add them one hour before serving. Cooked all day, dairy can separate.
• Pasta: add it at the end of the cooking time, or cook it separately and stir it in just before serving. Pasta that cooks for hours turns to mush.

Keep the lid on

Every time the lid comes off, heat escapes, and a slow cooker is slow to get it back. Penn State Extension notes that lifting the lid can drop the temperature by 10 to 15 degrees and add about 30 minutes to the cooking time. Lift it only to check whether the food is done.

Low or high?

Both settings cook the food fully. The difference is how long they take to get there, and in the published bands low takes about twice as long as high.

Low suits a dish you start in the morning and eat in the evening. High suits one you start after lunch. If you will be out for ten hours, choose a recipe from the last band, not the first, because a 20 minute recipe will be well overcooked by then.

What converts well

The best candidates are recipes that already cook gently in liquid: braises, stews, chili, pulled meats, beans and hearty soups. These are the dishes in the 50 minute to 3 hour band.

Quick recipes can be converted, but ask whether it is worth it. A 15 minute stir fry gains nothing from 4 hours in a slow cooker. The texture that makes it good comes from high heat and speed.

Recipes that need dry heat do not convert at all. A slow cooker cannot brown, crisp or roast. If browning matters to the flavor, brown the meat in a pan first and then move it to the cooker.

Tips and common mistakes

Cut vegetables to an even size. Root vegetables cook more slowly than meat in a slow cooker, so cut them small and put them at the bottom, nearer the heat.

Do not overfill. A cooker that is too full takes too long to heat. One that is under half full can cook too fast and dry out.

Season at the end. With no evaporation, flavors do not concentrate the way they do on the stove. Taste before serving and adjust the salt then.

Check early the first time. Once you know how your cooker handles a recipe, write the time on it.