Bean Soaking Time Calculator

Soaking dried beans before cooking does two useful things. It rehydrates them, which cuts the cooking time a long way, and it pulls out some of the oligosaccharides.
Those are the complex sugars that cause the digestive trouble beans are famous for, and most of them leave with the soaking water, which is the reason you drain it rather than cook in it.

Why soak beans? Dried beans are essentially dehydrated seeds. Without soaking, cooking times can be extremely long (2–3+ hours for large beans). Soaking softens the outer seed coat, begins rehydration, and allows the bean to cook more evenly.

Two soaking methods:

Overnight Soak (Traditional): Cover beans with 3× their volume in cold water. Let soak 8–12 hours (or overnight). Drain and rinse. This is the gentlest method and reduces cooking time by 25–50%. Best for most bean varieties.

Quick Soak: Place beans in a pot, cover with water, bring to a boil, boil 2 minutes, then remove from heat and let sit 1 hour. Drain and rinse. Nearly as effective as overnight soaking. Good when you forget to plan ahead.

Bean varieties and soaking times:

Cook times below are stovetop, at a simmer.

Quick soaking lands within a few minutes of the overnight column, so the calculator treats the two the same.

Important safety note: Kidney beans contain phytohaemagglutinin (PHA), a natural toxin that is destroyed only by boiling. Always boil kidney beans vigorously for at least 10 minutes before slow cooking.

Pressure cooker / Instant Pot: the big beans run 6–15 minutes at high pressure soaked, and 20–40 from dry. Quick-cooking ones sit well below that: black-eyed peas want 4–6 soaked and 10–12 dry, limas 5–8 and 12–15, and lentils are 8–10 either way because soaking them changes almost nothing.
All of those are minutes at pressure only. Budget another 10–15 for the pot to come up, and let the pressure fall on its own, because a fast release tears the skins off.

Slow cooker: 4–6 hours on low for the medium beans (black, kidney, navy, pinto) once soaked, and 6–8 from dry. Black-eyed peas and limas come in under that at 3–4 soaked. Chickpeas go over it at 5–6 soaked and 8–10 from dry, and lentils are done in 2–3 hours whether you soaked them or not. One exception matters more than the rest. Dried kidney beans in a slow cooker are the classic way people give themselves food poisoning, because low never reaches boiling and the phytohaemagglutinin survives. Boil them hard for 10 minutes on the stove first, then transfer.