Applying q=mc(deltaT)

How many calories are needed to raise the temperature from 20 degrees Celsius to 40 degrees Celsius for 200g of water?

The answer is 4000 calories
I know 1 calories is the energy to raise 1g of water by 1 degree Celsius so for 200g we need 200 * 20 = 4000 calories

But I couldn’t find this result by using the q=mc(deltaT) formula and I don’t understand why:
q=0,2kg * 4 * 20 kelvins
= 16000 joules

I’m not sure about the formula 1kcal=4000J because then I find 4cal as final result

What is my error?

Thank you!