Overdraft home loan vs fixed EMI — how prepayment works

If you've been offered SBI MaxGain, ICICI Money Saver, HDFC OD, or any "smart" home loan variant, you've been offered an overdraft (OD) home loan. It is not the same as a fixed EMI loan even if the sticker rate looks identical. Here's the actual mechanics.

The one-sentence difference

In a fixed EMI loan, interest is a schedule you signed. In an OD loan, interest is computed each month on whatever balance is actually outstanding — and any rupee sitting in the linked account reduces that balance for that month.

Fixed EMI: predictable, inflexible

• EMI is fixed at origination based on principal, rate, tenure.
• Every month, EMI splits into interest (on outstanding) and principal.
• To prepay, you make a separate lump-sum payment; the bank recalculates.
• Prepaid money is gone — you can't pull it back if you need it later.

Overdraft (flexi): flexible, sometimes cheaper

• You have a linked current account. Deposit any amount, any time.
• Interest is charged monthly on outstanding balance − parked amount.
• You can withdraw parked money back — it's not "prepaid", it's "parked".
• The "EMI" you pay reduces the balance; over time interest component shrinks faster than a fixed loan.
• Effective rate is usually 0.25–0.50% higher than the equivalent fixed loan, so it's not free flexibility.

A worked example

Same ₹50L principal at 8.5%, 20-year term. Fixed EMI = ₹43,391.

• Fixed: Pay ₹43,391 × 240 = ₹1.04 Cr total. Interest paid = ~₹54 lakh.
• OD, no parking: Same total (assuming same rate, which is rarely true — usually 0.25% higher).
• OD with ₹5L parked from year 2: Instantly saves ~₹42,500/yr in interest, which shortens the loan by ~2.5 years — without locking up the ₹5L.

When OD makes sense

• You maintain a healthy emergency fund and don't want to choose between emergency access and interest savings.
• You get variable-timing bonuses (RSUs vesting, annual bonus) and want to earn interest savings on them until you decide what to do.
• Your rate premium over the best fixed offer is under ~0.5%.

When fixed EMI wins

• You know you'll not maintain a large parked balance.
• You want maximum psychological simplicity — no temptation to withdraw the parked money.
• The OD premium is above ~0.5% over the best fixed offer available to you.