If you don’t fast for any of the days of Ramadan, you’ll be required to pay a charitable form of compensation. You must pay fidya (fidyah) for fasts missed out of necessity, that cannot be made up afterwards.

Fasting is for a fixed number of days, and if one of you be sick, or if one of you be on a journey, you will fast the same number of other days later on. For those who are capable of fasting (but still do not fast) there is a redemption: feeding a needy man for each day missed. Whoever voluntarily does more good than is required, will find it better for him; and that you should fast is better for you, if you only know. (Qur’an 2:184)

Fidya is paid for deliberately missing a fast with a valid reason to do so, however, kaffarah is only paid if you break a fast without a valid reason. The amount paid in fidya for each missed fast is equivalent to feeding one person. However, when paying kaffarah, the payment for is the equivalent of feeding 60 people.