Why has my ₹90 lakh home loan's principal reduced by only ₹6 lakh despite paying 60 EMIs? I asked ChatGPT

Home loan payment: I asked ChatGPT why the principal of my ₹90 lakh home loan hasn't reduced despite paying off ₹45 lakh over 60 EMIs. Here is what AI said.

My ChatGPT prompt

I took a home loan of ₹90 lakh for 25 years at 9% interest. My monthly EMI is ₹75,528. I have been paying my EMIs for 5 years, i.e., I have paid 60 EMIs, totalling ₹45 lakh (45,31,680). However, I found that my outstanding principal is ₹83,94,520. Despite paying about ₹45 lakh in EMIs, why has the outstanding principal reduced by only about ₹6 lakh?

I then asked ChatGPT to explain it to me as if I were a first-time borrower.

What ChatGPT said

A home loan = a financial product, not just ‘EMI’

When you take a loan, you’re effectively borrowing ₹90 lakh, agreeing to pay interest (cost of borrowing), and paying it back through EMIs over time.

Think of it like this:

> You’re not “buying a house with EMI”.

> You’re “renting money from the bank” and slowly buying the house.

How does EMI actually work?

Your EMI is calculated using a standard formula:

P x R x (1+R)^N / [(1+R)^N-1]

Where:

P = Loan amount ( ₹90,00,000)

R = Monthly interest rate (9% ÷ 12 = 0.75%)

N = Total months (300)

Crucial insight

The EMI is fixed, but inside it:

Interest is calculated on the remaining loan

Principal is whatever is left from EMI

So: Interest is always paid first, principal comes later.

Why does your principal barely reduce?

Month 1:

Interest = ~ ₹67,500

EMI = ₹75,528

Principal repaid = ~ ₹8,000

90% of EMI = interest

After 5 years (60 EMIs):

Total paid = ₹45.3 lakh

Principal reduced = ~ ₹6 lakh

Interest paid = ~ ₹39 lakh

Why does this happen?

This is because interest is calculated on ₹90 lakh initially, and that’s a huge base. So, early EMIs mostly serve interest.

This is called amortisation, front-loaded interest.

The hidden truth: Total cost of your loan

Let’s zoom out like an investor:

EMI: ₹75,528

Tenure: 300 months

Total paid over 25 years ≈ ₹2.26 crore

Breakdown:

Principal: ₹90 lakh

Interest: ~ ₹1.36 crore

Investor mindset takeaway

The bank earns more from your loan than you borrowed.

Why long tenure is a trap

Long tenure:

✔ Lower EMI (feels comfortable)

❌ Much higher total interest

Short tenure:

❌ Higher EMI

✔ Massive interest savings

Loan vs Investment: The real comparison

Your loan costs 9%. Any investment you make must beat 9% (post-tax) to make sense.

If not, prepaying the loan = guaranteed 9% return (risk-free)

What you should do now (practical strategy)

• Start prepaying early: Even ₹1–2 lakh extra per year directly reduces principal and cuts interest drastically
• Increase EMI yearly: Even a 5–10% increase can cut 5–8 years off your loan.
• Choose tenure reduction (not EMI reduction): When prepaying, always reduce tenure, not EMI.
• Treat a loan like a “negative investment”: Ask yourself whether I would invest at 9% guaranteed return? → Yes, that’s what prepayment gives you.

What most first-time borrowers misunderstand

❌ “I paid ₹45 lakh, so the loan should be reduced a lot”

✔ Reality: You paid mostly **interest**, not principal

❌ “EMI means equal payment toward the loan”

✔ Reality: Only total EMI is equal, not principal

❌ “Long tenure is safer”

✔ Reality: It’s **more expensive**

Simple analogy

Imagine you owe ₹90 lakh. Bank says: “First, pay my interest, then reduce your loan”. That’s exactly what’s happening.

SIP vs home loan prepayment? What's better

Compare loan interest rate vs expected investment return (post-tax)

• If SIP return consistently beats 9% after tax → SIP wins
• If not → prepayment wins

Choose prepayment if:

• You want guaranteed savings
• You’re risk-averse
• You’re early in loan tenure (like you are now)
• You don’t invest regularly already

Choose SIP if:

• You can stay invested for 10–15 years
• You’re okay with market ups and downs
• You believe returns > loan cost
• You already have an emergency fund + insurance

Ideal hybrid approach:

• 60–70% → SIP (wealth creation)
• 30–40% → Prepayment (risk reduction)

OR

• Do SIP normally
• Use bonuses/windfalls for prepayment

Your specific situation

You’re at year 5 of a 25-year loan, still in the high-interest phase. This means that prepayment right now gives maximum impact because every ₹1 prepaid saves interest for the next 20 years.

Simple rule of thumb

• If your loan rate > 8.5% → lean towards prepayment
• If your horizon > 10 years → SIP becomes attractive

If unsure, split the money.