Kaffarah is a much heavier expiation than simple Qada — it applies only when a fast is broken deliberately and without a valid Shar'i excuse (e.g. eating/drinking or marital relations on purpose during a Ramadan fast).
For each day violated, one of the following tiers of expiation applies (classically in this order of preference/obligation):
No longer applicable — slavery is abolished; this option is obsolete today.
Uninterrupted — breaking the streak (without valid excuse) generally means starting the 60 days over.
One day's food per person — the most commonly practiced option today when 60 consecutive days of fasting is not possible.
This is a simplified summary of a serious matter with real differences of opinion between schools of fiqh (e.g. on whether the 60 days must be fasted first, and on exactly what counts as deliberate breaking). Please consult a qualified local scholar for your specific case before acting on this calculation.