How much turmeric powder equivalent to 3 cm fresh turmeric?

To convert fresh turmeric to turmeric powder, a general guideline is that 1 inch of fresh turmeric is roughly equivalent to about 1 teaspoon of turmeric powder. Since 3 cm is approximately 1.2 inches, you would need about 1 to 1.5 teaspoons of turmeric powder to match the flavor and potency of 3 cm of fresh turmeric. Keep in mind that the potency and flavor may vary, so it's best to adjust according to taste.