Fixed vs Variable Mortgage Rate Calculator
Cost comparison fixed vs variable mortgage.
Compare cost of fixed vs variable mortgage rate over the fixed period. See break-even point. Enter mortgage balance and fixed rate to see total cost of each.
What this tool does
Enter mortgage balance, fixed rate, current variable rate, and fixed period years. The tool shows total cost of each.
Enter Values
Formula Used
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Disclaimer
Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.
Fixed vs variable rate mortgage choice depends on rate spread and risk tolerance. Fixed gives certainty at typically slight premium. Variable cheaper now but risks rate rises. Calculator shows immediate cost comparison — fixed only wins if variable rises significantly.
A worked example
Try the defaults: mortgage balance of 200,000, fixed rate of 5.5%, current variable rate of 5%, fixed period of 5. The tool returns Variable. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.
What moves the number most
The result responds to Mortgage Balance, Fixed Rate, Current Variable Rate, and Fixed Period. Two inputs usually tip the answer one way or the other. Identify which ones matter most by flipping each value past a round threshold and watching whether the winning option changes.
The formula behind this
Simplified interest cost. Balance × rate × years. Lower cost = winner at current rates. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.
What the headline rate hides
Lenders quote a rate; what you pay is a blend of that rate, fees, insurance, and any early-repayment penalty built into the product. The figure here isolates the core interest cost so you can compare like-for-like across deals — then add the other costs separately before signing anything.
What this doesn't capture
The figure excludes arrangement fees, valuation costs, legal fees, insurance, and any early-repayment charges — those can add several thousand to the headline cost. Rate changes at renewal for fixed-term deals will shift the picture further. Use this for the core interest/principal math and add the other costs on top.
Fixed vs variable produces cost comparison based on the inputs provided.
Inputs
This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.
Sources & Methodology
Methodology
Simplified interest cost. Balance × rate × years. Lower cost = winner at current rates.
Frequently Asked Questions
Should I choose fixed or variable?
How long to fix?
What about caps?
Future rate expectations?
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