1. The cooking time of boiled sweet potato varies with the size of sweet potato. Generally, sweet potatoes are cut into pieces with uniform size of 1 cm, and it usually takes about 10 minutes after water is boiled.

2. But if the whole sweet potato is cooked, it will take 15-20 minutes for the palm-sized sweet potato to be cooked after the fire is boiled.

3. To judge whether the sweet potato is ripe, you can poke it from the surface of the sweet potato with chopsticks. If you can poke the sweet potato smoothly, it means that the sweet potato is cooked thoroughly. If not, you need to cook 1-5 minutes according to the situation.