For most standard corned beef briskets (about 3–4 pounds), plan on 8–10 hours on LOW or 4–6 hours on HIGH in the crock pot, until it’s fork‑tender and slices easily.

Quick Scoop

  • 3–4 lb corned beef on LOW: 8–10 hours.
  • 3–4 lb corned beef on HIGH: 4–6 hours.
  • Meat is done when:
    • A fork slides in with almost no resistance.
    • Internal temperature is at least 195°F for shreddable, tender meat.
  • Let it rest 10–15 minutes before slicing, cutting against the grain.

Simple Step‑By‑Step

  1. Rinse corned beef (optional), then place in crock pot, fat side up.
  2. Sprinkle with spice packet; add enough water (or broth/beer) to come about ½–1 inch up the sides.
  3. Cook:
    • LOW: 8–10 hours.
    • HIGH: 4–6 hours.
  4. Add potatoes/carrots for the last 2–3 hours, cabbage for the last 1–2 hours so they don’t overcook.
  5. Check tenderness after the minimum time; continue in 30‑minute increments if still tough.

Size & Setting Cheat Sheet

  • 2–3 lb brisket:
    • LOW: about 7–8 hours.
    • HIGH: about 4 hours.
  • 4–5 lb brisket:
    • LOW: about 9–10 hours.
    • HIGH: about 5–6 hours.
  • Flat cut usually cooks a bit more evenly than point cut; point cut may need a little extra time for all the fat/connective tissue to break down.

Little Story‑Style Tip

Think of corned beef like a stubborn but sweet character in a story: rush it and it stays tough and grumpy, give it a long, warm bath on LOW heat and it turns soft, rich, and friendly on your plate. If you’re ever unsure, keep it going a bit longer on LOW—undercooked corned beef is chewy; slightly overcooked in the crock pot is usually still juicy and shreddable. TL;DR: For “set it and forget it,” put a 3–4 lb corned beef in the crock pot on LOW for about 8–10 hours, then check for fork tenderness before serving.