Mortgage Calculator: Know Your Exact Monthly Repayment

Buying a home is the largest financial decision most people will ever make. Yet many first-time buyers have no clear picture of what their monthly repayment will actually be. Our free mortgage calculator changes that.

What does a mortgage calculator tell you?

Our calculator gives you five key numbers:

• Monthly repayment covering principal plus interest
• Total interest paid over the full loan term
• Total cost of the property including all interest
• Full amortisation schedule year by year
• Impact of different deposit amounts on your payment

How to use the calculator

1. Enter the property price
2. Enter your deposit amount or percentage
3. Enter the annual interest rate
4. Choose your loan term (20 or 30 years is most common)
5. Select your currency (ZAR, USD, GBP, EUR)

Understanding your results

Your monthly repayment splits between principal (reduces what you owe) and interest (cost of borrowing). In early years, most of your payment goes to interest. This is why total interest paid over 30 years often exceeds the original loan amount.

Real example: R2,000,000 home in South Africa

Property price: R2,000,000 Deposit: R200,000 (10%) Loan amount: R1,800,000 Interest rate: 11.75% Term: 20 years Monthly bond repayment: approximately R19,700 Total interest over 20 years: approximately R2,928,000 Total cost: approximately R4,928,000

Increasing your deposit from 10% to 20% saves far more than R200,000 in interest over the life of the loan.

How interest rates affect your repayment

On a R1,800,000 loan over 20 years: At 10%: approximately R17,370 per month At 11.75%: approximately R19,700 per month At 13%: approximately R21,600 per month

Use our calculator to stress-test different rate scenarios before committing.

Tips for first-time home buyers

1. Save a larger deposit. Every extra percentage reduces monthly payment and total interest.
2. Get pre-approved before you shop.
3. Factor in additional costs: transfer duty, conveyancing fees, home insurance.
4. Consider a shorter term. A 20-year bond costs significantly less interest than 30 years.
5. Make extra payments when you can. Even one extra payment per year shaves years off.

Frequently asked questions

What is the difference between a mortgage and a bond? They are the same thing. In South Africa home loans are called bonds. In the US, UK and Australia they are called mortgages.

Does the calculator include property taxes and insurance? The basic calculation covers principal and interest. You can optionally add monthly tax and insurance estimates.

What interest rate should I enter? Use the rate your bank has quoted you. In South Africa most bonds are priced at prime plus 0-2 percentage points.

What happens if interest rates change? Run the calculator again with the new rate. Many South African bonds are variable-rate.

How much deposit do I need? Most banks require a minimum 10% deposit. A 20% deposit eliminates mortgage insurance requirements in many countries.