Mortgage Calculator — Monthly Payments, Affordability & Amortization

The standard amortization formula is: EMI = P × r × (1+r)^n / ((1+r)^n − 1). P is the loan amount (home price minus down payment), r is the monthly interest rate (annual rate ÷ 12 ÷ 100), and n is the total number of monthly instalments. Each payment is split between interest (calculated on the outstanding balance) and principal. In the early years, most of the payment is interest; later, it flips. This formula works identically for US, UK, Indian, Canadian or any other mortgages — only interest-rate conventions and loan structures vary by country.

Affordability rules vary by country: US lenders use the 28/36 rule (housing costs under 28% of gross income, total debt under 36%); UK lenders cap at 4.5× household income; Indian banks use a Fixed Obligation to Income Ratio (FOIR) of 40-50%; Canadian lenders use GDS/TDS ratios (32%/40%). A household earning $80,000 / £40,000 / ₹12L typically qualifies for $250k / £180k / ₹50L respectively. The actual figure depends on credit score, deposit, monthly outgoings and lender stress tests. Use the calculator above to test scenarios — banks may sanction more than is comfortable.

A 15-year mortgage has a higher monthly payment but dramatically less total interest. Example on a $300,000 loan at 6.0%: 30-year payment is $1,799/month with $347,514 total interest; 15-year payment is $2,531/month with $155,683 total interest — saving about $192,000 in interest. The trade-off is monthly cash flow. If the shorter EMI cramps other financial goals, the 30-year-with-prepayments middle path often beats either extreme. Run both scenarios in the calculator with your loan to see the numbers side-by-side.

On a long-term mortgage the interest you pay can almost match the principal — sometimes exceed it. Borrow $300,000 at 6.5% for 30 years and the monthly payment is around $1,896. Multiply by 360 months and you've paid about $682,800 total — meaning $382,800 is pure interest. Borrow £200,000 at 4.5% for 25 years and total interest is roughly £133,000. The numbers shift significantly with rate and tenure — even a 0.5% rate change moves total interest by tens of thousands. Use the calculator to see your exact figure.

With an interest-only mortgage, your monthly payment covers only the interest on the loan — the capital stays the same throughout the term. So a $200,000 mortgage at 6% costs $1,000/month interest-only versus $1,199/month on a 30-year repayment. The lower payment is the appeal, but at the end of the term you still owe the full $200,000 as a lump sum. In the US, interest-only is rare for residential mortgages now. In the UK it's available with a credible repayment plan, and is common for buy-to-let. Indian home loans are almost always full repayment.

A lot, often more than people expect. On a $300,000 mortgage at 6.5% over 30 years, paying just $100 extra a month saves about $43,000 in total interest and pays the mortgage off about 4 years early. Paying $300 extra saves about $108,000 and clears it 8 years sooner. Most US and Canadian lenders allow unlimited overpayments. UK lenders typically allow 10% per year without early repayment charge during a fixed-rate term. Indian lenders permit prepayment without penalty on floating-rate loans. Overpaying early in the term saves the most.

An investment property mortgage is for a property you'll let out, not live in. In the UK, buy-to-let (BTL) is the standard term — assessed mostly on rental income with an Interest Coverage Ratio (ICR) of 125-145%, typically interest-only, 20-25% minimum deposit. In the US, investment property loans are conventional mortgages with stricter terms — usually 20-25% down, higher rates than primary-residence loans, lender review of rental income. In India, lenders treat second-home loans similarly to first-home but at slightly higher rates and lower LTV ratios.

In the US, the 28/36 rule suggests a $300,000 mortgage at 6.5% needs household gross income around $80,000-$90,000. In the UK, at 4.5× income, a £300,000 mortgage needs around £66,700 household income. In India, a ₹50 lakh home loan at 8.5% over 20 years needs household income around ₹1.5-2 lakh per month (FOIR 50% rule). All assume modest other debts and a reasonable credit score. Lenders may stress-test you at higher rates, capping your borrowing below the headline multiple.

Islamic mortgages are Sharia-compliant — they replace interest (riba, forbidden in Islamic finance) with structures based on rent or partnership. The two common forms are Diminishing Musharaka (you and the bank co-own the property; you buy out the bank's share over time and pay rent on the remaining portion) and Ijara (you rent from the bank and buy at term-end). UK providers include Al Rayan Bank and Gatehouse Bank; US providers include Guidance Residential and University Islamic Financial; UAE providers include ADIB and Dubai Islamic Bank. Total cost works out similar to a conventional mortgage, but the contractual structure is fundamentally different.

Beyond the principal-and-interest payment, expect: US — annual property tax (1-2% of home value typical, varies by state), homeowners insurance ($1,000-2,500/year), PMI if LTV > 80%; UK — Stamp Duty Land Tax on purchase (0-12% bands), buildings insurance, council tax annually; India — registration & stamp duty 5-8% of property value on purchase, GST 5% on under-construction, annual property tax. Lenders sometimes quote a PITI figure (Principal, Interest, Taxes, Insurance) to gauge affordability. Always budget the all-in monthly cost.