The formula below can be used to calculate Loan EMI:

EMI = [P x R x (1+R)^T]/[(1+R)^ (T-1)].

The variables used here stand for:
P- Principal Amount of the Loan
EMI - Equated Monthly Installments
R - Monthly Rate of Interest on the Loan (Annual rate of interest divided by 12)
T - Tenure of the Loan (in months) or the no. of installments to be paid

When a lender disburses a loan in installments, you do not have to pay EMIs until you get the full amount disbursed. However, till the time you get full loan amount, you have to pay the applicable interest on whatever amount is disbursed to you. That amount is known as pre-EMI.

Yes, according to the Income Tax Act, 1961, you can avail the following tax benefits on your Home loan EMIs:

Section 80C - Upto Rs 1.5 lakhs can be claimed every year on the principal amount paid towards loan.
Section 24 - Upto Rs 2 lakhs can be claimed as deduction on the interest you pay every year.
Section 80EE - An extra deduction of upto Rs 50,000 on interest paid can be claimed, subject to certain terms and conditions.

If you fail to pay your home loan EMI on time, the lender will charge you a late payment fee. In addition, the lender may also charge you some extra interest as penalty. Further, if you continue to default on your payments, the lender may send you a legal notice to recover the dues. Remember, any default on EMI payment will also impact your credit score.