The difference between total costs and your expected contribution is your estimated eligibility for financial aid, which will likely include loans and work-study as well as grants.
Some private colleges modify the calculations somewhat when awarding aid from their own funds.
If you're several years away from the first tuition bill, you can use this calculator to help set your savings goal for college expenses. But remember that if your income or assets increase faster than inflation, your aid eligibility will probably shrink. Please use only numeric characters and decimal points in your input. If the student is independent, this includes the student, the student's spouse and children who meet the support criteria. If the student is not independent, this number includes the parents, the student and any siblings who will meet the support from household criteria.