Fidyah and Kaffarah are two types of missed fasts during Ramadan. For fasts missed through necessity, pay Fidyah. For fasts missed unnecessarily, pay Kaffarah.
Fidyah and Kaffarah are two terms that are specifically related to Ramadan.
When someone is not able to fast in Ramadan and cannot make them up afterwards (primarily due to ill health or pregnancy) they need to pay for someone else to be fed.
It is at a rate of $9 per day that is missed. (This should provide one person with 2 meals or two persons with 1 meal.) If someone misses all the fasts of Ramadan, it would amount to $270.
Kaffarah is the compensation that one needs to pay if a fast is deliberately missed or broken in the month of Ramadan without a valid reason.
To atone for the missed/broken fast, the one that missed/broke the fast must either fast continuously for 60 days, or feed 60 poor people at a rate of $9 per day per person. This amounts to $540 Kaffarah for each missed/broken fast