Home›Mortgage & Overpayment Calculator — Free Mortgage Calculator UK
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Mortgage Calculator
Free mortgage repayment calculator — monthly payments, total interest & full amortisation
Enter the amount, the rate and the term and you'll get the monthly payment, the total interest over the life of the loan, and a full year-by-year breakdown. It covers repayment, interest-only, fixed and offset mortgages and adjusts for the UK, the US, Canada and Europe, so the figures suit wherever you're buying rather than a single market.
📍 Step 1 — Select Your Region
Average mortgage rate for this region: 4.85%Rates are indicative averages. Your actual rate may vary.
🏦 Step 2 — Mortgage Type
🏠Repayment
Capital + interest Balance clears at end
💸Interest Only
Pay interest only Capital due at end
🔒Fixed Rate
Rate locked in for fixed period
📊Variable Rate
Rate can change follows base rate
📈Tracker
Tracks central bank base rate ± margin
⚖️Offset
Savings reduce interest charged
🔀ARM / 5-1
Fixed then adjusts annually (USA/Canada)
🏷️Discount
Discount off SVR for set period
⚠️ Interest-only reminder: Your monthly payment covers interest only. The full loan balance of will be due as a lump sum at the end of the term. Make sure you have a repayment strategy in place.
📋 Step 3 — Property & Loan Details
£
£
or
%
—
% p.a.
Auto-set to regional average · editable
yearsmonths
For payoff date calculation
£
Extra amount paid each month
£
Single overpayment made today
£
Added to loan or paid upfront
📊 Mortgage Summary
Monthly Payment—
Loan Amount—
Total Repaid—
Total Interest—
Interest %—
Payoff Date—
Property Price—
Deposit—
LTV Ratio—
Mortgage Type—
Interest Rate—
Term—
PrincipalInterest
Loan-to-Value0%
💚 Overpayment saving:
📅 Payment Breakdown
Year 1 Interest
—
Year 1 Principal
—
Balance After Year 1
—
Balance at Midpoint
—
Equity at Year 5
—
Equity at Year 10
—
📈 Annual Amortisation Schedule
Year-by-year breakdown of principal, interest and remaining balance
Year
Principal Paid
Interest Paid
Total Paid
Remaining Balance
% Paid Off
🧮 How this is calculated ▼
Monthly repayments use the standard amortisation formula:
M = P × [ r(1 + r)n ] ÷ [ (1 + r)n − 1 ]
P = amount borrowed · r = monthly interest rate (annual rate ÷ 12) · n = total monthly payments (years × 12).
Each payment covers that month's interest first, and whatever's left reduces the balance. Early on, most of your payment is interest; as the balance shrinks, more goes to capital — which is why overpayments early save the most interest. Total interest = (M × n) − P.
❓ Frequently Asked Questions
How is a mortgage monthly payment calculated? ▼
For a repayment mortgage: M = P × [r(1+r)^n] ÷ [(1+r)^n − 1], where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments. The calculator handles all mortgage types including interest-only, offset, and ARM.
What is LTV (Loan-to-Value) and why does it matter? ▼
LTV is the mortgage amount divided by the property value, expressed as a percentage. A £200,000 mortgage on a £250,000 property = 80% LTV. Lenders offer better rates at lower LTVs (typically below 75–80%), and LTV above 90–95% often requires mortgage insurance or is refused entirely.
What is the difference between a fixed-rate and variable-rate mortgage? ▼
A fixed-rate mortgage locks your interest rate for a set period (typically 2, 3, or 5 years), giving payment certainty. A variable-rate mortgage can move up or down with the lender's standard variable rate (SVR), meaning your payments can change at any time.
How much does an overpayment save? ▼
Even small monthly overpayments significantly reduce total interest and can shorten your term by years. The calculator shows exactly how much interest you save and how many months earlier you'd pay off the mortgage when you enter a monthly overpayment amount.
What is the average mortgage rate in the UK in 2025? ▼
Average 2-year fixed rates in the UK were around 4.5–5% in early 2025, and 5-year fixed rates around 4.3–4.8%, depending on LTV. The calculator auto-fills regional average rates but you can edit these to match your personal quote.
✓ 100% free, no sign-up🔒 Private — runs in your browser🔄 Updated 2026