To boil Brussels sprouts, the typical cooking time ranges from about 4 to 12 minutes depending on their size and whether they are whole or halved:

• For whole Brussels sprouts, boil for approximately 6 to 10 minutes until they are bright green and tender but still slightly firm (al dente)

• If the sprouts are halved or smaller, boiling for 3 to 5 minutes is usually sufficient to achieve tenderness without overcooking

• Some sources recommend boiling for 4 to 6 minutes to keep them crisp-tender and avoid mushiness or bitterness caused by overcooking

• To stop the cooking process and preserve the bright green color, you can immediately transfer the boiled sprouts to an ice bath after draining

In summary, boil Brussels sprouts for about 4 to 6 minutes if halved or smaller, and 6 to 10 minutes if whole, testing for tenderness with a fork or knife to suit your preference. Avoid overcooking to prevent bitterness and mushiness