Answer
Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Skipping fasting due to exams is not a valid excuse in Islam. Ramadan fasting is an obligation, and only those with valid reasons—such as illness, travel, pregnancy, or old age—are permitted to miss it. Students should plan their study schedules efficiently to balance both their religious duties and academic commitments.
In this regard, Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, states:
It is not permissible to break the fast for the reason you mentioned, rather it is haram, because it is not included in the reasons for which one is allowed to not fast in Ramadan.
Moreover, it should be noted that fasting in Ramadan is an obligation upon every accountable Muslim, and no one is excused from fasting at the time of fasting except for those who have valid excuses, who are granted the concession of being allowed not to fast, such as the sick, travelers, pregnant and breastfeeding women, the very old, and those who are forced to break their fast.
Allah Almighty knows best.
Source: www.islamqa.info