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Mortgage Calculator

Monthly mortgage payments and total interest. See impact of extra payments.

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Compound Interest Calculator

Example 1 — Lump sum, no contributions

A = 1,00,000 × (1.10)^10 ≈ ₹2,59,374 — more than 2.5× growth

Open Compound Interest →

📘 What is the Mortgage Calculator?

A mortgage is likely the single largest financial commitment most people ever make — often 15-30 years of monthly payments, with the total interest paid frequently exceeding the original loan amount. This calculator computes your exact monthly payment, shows the full amortization breakdown, and quantifies precisely how much faster you can be mortgage-free with extra payments.

⚙️ How Mortgage is calculated

How the monthly payment is calculated

The standard mortgage formula is the same as any amortizing loan: M = P × r × (1+r)ⁿ ÷ [(1+r)ⁿ − 1], where P is the loan principal (home price minus down payment), r is the monthly interest rate, and n is the total number of monthly payments. This produces a fixed payment that, over the full term, exactly pays off both principal and interest.

Why your down payment matters more than it seems

A larger down payment does two things simultaneously: it reduces the principal P in the formula above (lowering every future payment), and in many markets it can remove the requirement for private mortgage insurance (PMI) — an additional monthly cost charged when the loan-to-value ratio is high. Crossing the 20% down payment threshold often produces savings beyond the simple interest-rate math.

Front-loaded interest, back-loaded principal

In the early years of a 20-30 year mortgage, the overwhelming majority of each payment goes toward interest, not principal — because interest is calculated on the (still-large) outstanding balance. This is why making extra payments in the first 5-10 years has a dramatically larger effect on total interest than making the same extra payments near the end of the term.

The true cost of "just a bit more per month"

Because of how amortization compounds, a relatively small consistent extra payment — even 5-10% of your regular payment — can cut years off a 30-year mortgage and save a substantial fraction of total interest. This calculator's extra-payment field shows this effect directly, in both years saved and rupees/dollars saved.

Monthly mortgage payment

M = P × r × (1+r)ⁿ ÷ [(1+r)ⁿ − 1]

P = loan principal, r = monthly interest rate, n = total number of payments

🧮 Worked examples

Example 1 — Standard 30-year mortgage

₹50,00,000 loan at 8% annual interest for 30 years (360 months), no extra payments.

→ Monthly payment ≈ ₹36,700 · Total interest over 30 years ≈ ₹82 lakh — more than 1.6× the loan amount

Example 2 — Same loan, 15-year term

Same ₹50,00,000 at 8%, but a 15-year term (180 months).

→ Monthly payment ≈ ₹47,800 (about 30% higher) · Total interest drops to ≈ ₹36 lakh — less than half of the 30-year scenario

Example 3 — Extra payments on the 30-year loan

Example 1's loan, with an extra ₹5,000 paid every month from day one.

→ Loan paid off roughly 8-10 years early, saving approximately ₹25-30 lakh in total interest

💡 Original insights & how to use this calculator

Choosing between 15-year and 30-year terms

A 15-year mortgage has a higher monthly payment but dramatically lower total interest — often less than half. Run both scenarios through this calculator with your actual numbers: if the 15-year payment fits comfortably in your budget, the long-term savings are substantial. If it would strain your finances, the 30-year term with optional extra payments offers similar flexibility with a lower mandatory minimum.

Is it worth buying points to lower your rate?

Lenders sometimes offer to lower your rate in exchange for an upfront fee ("points"). Run this calculator at both your quoted rate and the reduced rate — the difference in total interest over the time you expect to hold the mortgage tells you whether the upfront cost is worth it.

Refinancing math: when does it pay off?

If rates have dropped since you took your mortgage, refinancing resets your amortization schedule. Compare your current remaining balance and rate against a new loan at the lower rate (including any refinancing fees) — this calculator helps quantify the interest savings to weigh against those costs.

Building extra payments into your budget gradually

Rather than committing to a large extra payment immediately, try modelling smaller amounts first — even an extra ₹2,000-3,000/month. Because of how amortization compounds, even modest extra payments made consistently over many years produce meaningful reductions in both loan term and total interest.