A mortgage is a loan secured against a property. The lender provides funds to buy the property, and in return you agree to repay the loan with interest over a set term — typically 25 to 30 years. The property itself is used as collateral: if you stop making payments, the lender has the legal right to repossess and sell it to recover the debt.

How does a mortgage work?

When you take out a mortgage, you borrow a sum of money from a bank or building society to buy a property. Each monthly payment covers two components: interest (the cost of borrowing) and principal (reducing the outstanding loan balance). Over time, the balance reduces and you own more of your home — this is called equity. When the mortgage is fully repaid, you own the property outright.

What is LTV in a mortgage?

LTV stands for Loan-to-Value ratio — it expresses your mortgage amount as a percentage of the property's value. If you buy a £300,000 home with a £60,000 deposit (20%), your mortgage is £240,000 — an 80% LTV. A lower LTV generally means lower interest rates because the lender's risk is reduced. First-time buyers often start with a 90-95% LTV mortgage.

What is the difference between a repayment and interest-only mortgage?

A repayment mortgage (also called capital repayment) reduces your loan balance every month — at the end of the term, you own the property outright. An interest-only mortgage only pays the interest each month, leaving the full loan outstanding at the end of the term. You must have a separate plan (investments, ISA, inheritance) to repay the loan at maturity. Most residential buyers use repayment mortgages; interest-only is more common in buy-to-let.

How long does a mortgage last?

Standard UK mortgage terms range from 10 to 35 years — 25 years has traditionally been most common, but 30-35 year terms are increasingly popular as house prices have risen and buyers want lower monthly payments. Longer terms mean lower monthly payments but more total interest paid over the life of the loan.

what is a mortgage -

What Is a Mortgage?

A mortgage is a loan secured against a property. The lender — usually a bank or building society — provides the funds to purchase the property. In return, you agree to repay that loan, plus interest, over a set number of years. Critically, the property itself serves as collateral: if you stop making payments, the lender has the legal right to repossess and sell the property to recover the outstanding debt.

This security — the property as collateral — is what makes mortgages possible at all. Because the lender can recover their money by selling the property if necessary, they are willing to lend large sums at relatively low interest rates compared to unsecured borrowing like personal loans or credit cards. A personal loan at £20,000 might charge 8–15% interest. A mortgage of £200,000 might charge 4–5% — the lower rate reflects the lender's security.

The word "mortgage" literally means "death pledge" in Old French — a reference to the fact that the agreement ends either when the debt is fully repaid (it "dies") or when the borrower dies. Today it simply describes any property-secured loan, and the vast majority are repaid through monthly payments long before either party ceases to exist.

A mortgage is a secured loan used to buy property. The property is collateral — giving the lender security and you a lower interest rate. You repay the loan plus interest over a fixed term (typically 25–35 years). During this period, the lender holds a legal charge over the property. When fully repaid, you own the property outright with no encumbrances.

Equity vs Debt — How Ownership Builds Over Time

One of the most important concepts in understanding a mortgage is equity — the portion of the property you actually own. When you first buy a home with a mortgage, equity equals your deposit. As you make monthly payments, your loan balance reduces and your equity grows. Use the slider below to see how this changes over a 25-year repayment mortgage:

🏠 How Equity Builds Over 25 Years

£300,000 property · £240,000 mortgage (80% LTV) · 4.5% fixed rate

Your Equity (ownership)

£60,000

20% of property

Outstanding Mortgage

£240,000

80% of property

Property value breakdown

Equity (yours) Mortgage (lender's)

Drag to see equity at different points in time

Year 0 — start of mortgage

The Four Key Components of Every Mortgage

💰

Principal

The original amount borrowed — the loan itself. Each monthly repayment reduces the principal (on a repayment mortgage). As the principal falls, the monthly interest charge also falls.

E.g. You borrow £240,000 — that is your principal

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Interest

The cost of borrowing — charged as a percentage (rate) applied to the outstanding principal each month. This is how the lender makes money. Higher balance = higher monthly interest charge.

At 4.5% on £240K: ~£900/month interest in year 1

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Loan-to-Value (LTV)

Your mortgage as a percentage of the property's value. A £240K mortgage on a £300K home = 80% LTV. Lower LTV means better rates — lenders take less risk when your equity stake is larger.

80% LTV = £60K deposit on £300K property

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Term

The number of years to repay the mortgage. Standard UK terms: 20–35 years. Longer term = lower monthly payments but much more total interest paid over the life of the loan.

25yr vs 35yr: same rate, same loan — very different total cost

How Monthly Mortgage Payments Are Calculated

Each monthly mortgage payment (on a repayment mortgage) covers two things: interest on the outstanding balance, and principal repayment that reduces the loan. The split between these two changes significantly over time — a concept called amortisation.

In the early years, the majority of each payment covers interest — because the outstanding balance is large. As the years pass and the balance falls, the interest portion decreases and the capital repayment portion increases. By the final years of a mortgage, almost all of each payment is reducing the outstanding balance.

Year	Monthly Payment	Interest Portion	Principal Portion	Balance Remaining
Year 1	£1,330	£900 (68%)	£430 (32%)	£234,840
Year 5	£1,330	£840 (63%)	£490 (37%)	£215,600
Year 10	£1,330	£740 (56%)	£590 (44%)	£187,200
Year 15	£1,330	£600 (45%)	£730 (55%)	£149,600
Year 20	£1,330	£400 (30%)	£930 (70%)	£98,200
Year 25	£1,330	£50 (4%)	£1,280 (96%)	£0

Illustrative figures: £240,000 mortgage at 4.5% over 25 years. Actual figures depend on exact rate and term. Payment stays the same throughout — but the split between interest and principal shifts dramatically over time.

💡 Why Early Overpayments Are So Powerful

Because early payments are mostly interest, making overpayments in the first years hits the principal directly — reducing the balance that all future interest is calculated on. A £10,000 overpayment in year 1 can save £15,000–£20,000 in interest over the life of a 25-year mortgage at 4.5%. This is why financial advisers consistently recommend overpaying a mortgage when possible — the compound benefit is significant.

Repayment vs Interest-Only — The Critical Choice

✅ Repayment (Capital Repayment) Mortgage

✓Monthly payment covers interest + loan repayment

✓Balance reduces every month — you build equity steadily

✓At the end of the term: you own the property outright

✓No separate repayment vehicle needed

~Higher monthly payments than interest-only

✅ Standard choice for residential buyers — guaranteed outcome

⚠️ Interest-Only Mortgage

~Monthly payment covers interest only — loan stays the same

~Lower monthly payments — but no equity built via payments

~At term end: full loan still outstanding — must be repaid

~Requires separate repayment plan (ISA, investments, pension)

✗If repayment plan fails — serious financial risk

⚠️ Common in buy-to-let — rarely recommended for residential without robust repayment plan

Main Types of Mortgage Rate

The interest rate type determines how your rate — and therefore your monthly payment — behaves over time. This choice matters significantly in a period when rates are changing.

Fixed Rate Mortgage

Your interest rate is guaranteed for a set initial period — typically 2, 3, or 5 years. Your monthly payment stays exactly the same regardless of what the Bank of England does. After the fixed period, you revert to the lender's Standard Variable Rate (SVR) — at which point most people remortgage.

✅ Certainty — budget exactly for the fixed period

❌ If rates fall, you're locked at the higher rate

Flexible

Variable Rate (Tracker)

Your rate tracks the Bank of England base rate plus a fixed margin. If the BoE cuts rates, your payment falls. If it raises rates, your payment rises. Provides flexibility — often no early repayment charges — but monthly costs are unpredictable.

✅ Benefits immediately from rate cuts

❌ Payments rise if BoE raises rates

Avoid

Standard Variable Rate (SVR)

The lender's default rate that applies after an initial deal period ends. Set entirely by the lender — not directly tied to BoE decisions. Almost always significantly higher than competitive deals. Falling onto an SVR is the most common mortgage mistake.

~ No early repayment charges — can remortgage freely

❌ Typically 1–2% higher than best available deals

Offset / Flexible

Offset Mortgage

Links your mortgage to a savings account. The savings balance "offsets" your mortgage balance — you only pay interest on the difference. No interest earned on savings, but mortgage interest saved can exceed savings interest at comparable rates. Useful for higher-rate taxpayers.

✅ Tax-efficient for higher-rate taxpayers

❌ Often higher rate than standard fixed deals

Mortgage Monthly Payment Calculator

Use the calculator below to estimate your monthly mortgage payment. Useful for understanding how different property prices, deposits, and rates affect affordability.

🏠 Mortgage Payment Calculator

Estimate your monthly repayment — educational illustration only.

Property Price

Deposit Amount

Annual Interest Rate (%)

Mortgage Term (years)

Mortgage Type

Currency

📊 Your Mortgage Estimate

🏠

Enter details and
click Calculate
to see your estimate

The Mortgage Journey — From Application to Completion

Understanding each stage of getting a mortgage removes a lot of the anxiety first-time buyers feel. The process is structured and predictable, though it can feel complex at first.

Check Your Credit Report & Finances

Before approaching any lender, review your credit report (free at Experian, Equifax, or TransUnion), calculate your maximum deposit, and assess your income and outgoings. Lenders will examine all of these in detail.

Timing: Before you start property searching

Get a Mortgage in Principle (MIP)

Also called an Agreement in Principle (AIP) or Decision in Principle (DIP). A lender or broker indicates how much they're likely to lend based on a soft credit check. This gives you a budget for property searching and shows sellers you're serious.

Timing: Before making offers · Takes 1–24 hours

Find a Property & Make an Offer

Search within your confirmed budget, make an offer, and get it accepted. Once accepted, instruct a solicitor (conveyancer) to handle the legal side of the purchase — they'll carry out searches and handle contracts.

Timing: Weeks to months depending on market

Submit Full Mortgage Application

Provide full documentation to your lender — payslips, bank statements, ID, proof of deposit. The lender assesses your affordability and creditworthiness. This is the formal application after offer acceptance.

Timing: 2–6 weeks to receive mortgage offer

Property Valuation & Survey

The lender commissions a valuation to confirm the property is worth what you're paying. Separately, you should commission an independent survey (Homebuyer Report or Full Structural Survey) to check the property's condition. These are different — the valuation protects the lender, the survey protects you.

Timing: During application processing · 1–3 weeks

Receive Formal Mortgage Offer

The lender issues a formal mortgage offer — a legally binding document confirming the loan amount, rate, term, and conditions. Review this carefully with your solicitor. You have a reflection period before accepting.

Timing: Valid for 3–6 months depending on lender

Exchange of Contracts

Both parties sign and exchange contracts, making the sale legally binding. You pay your deposit (typically 5–10% of purchase price) at this stage. A completion date is agreed. Withdrawing after exchange incurs financial penalties.

Timing: Usually 1–4 weeks before completion

Completion — You Get the Keys

Your solicitor transfers the remaining funds (mortgage + balance of deposit) to the seller's solicitor. The property legally transfers to you. You collect the keys and the mortgage begins. First payment typically due around 1 month later.

Timing: Completion day — typically 8–16 weeks from offer accepted

Essential Mortgage Glossary

These are the terms you'll encounter throughout your mortgage journey. Knowing them prevents confusion and helps you ask the right questions.

LTV Loan-to-Value. Your mortgage as a percentage of the property's value. 80% LTV = 20% deposit. Lower LTV = better rates and more lender options.

AIP / MIP Agreement/Mortgage in Principle. Lender's preliminary statement of how much they'd likely lend. Not a guaranteed offer — full assessment happens on application.

SVR Standard Variable Rate. The lender's default rate when an initial deal expires. Usually significantly higher than competitive deals. Most borrowers should remortgage before reverting to SVR.

ERC Early Repayment Charge. A penalty for repaying or switching mortgage during a fixed or discounted rate period. Typically 1–5% of the outstanding balance. Reduces to zero once the initial deal expires.

Conveyancer Solicitor handling the legal transfer of property. Conducts searches (local authority, drainage, environmental), reviews contracts, and transfers funds on completion day.

Stamp Duty SDLT — UK property purchase tax. Paid on property purchases above threshold values. Rates vary by property value, buyer type (first-time vs second property), and location (different rules in Scotland and Wales).

Amortisation The gradual repayment of a loan over time. Each payment covers interest + principal. Early payments are mostly interest; later payments are mostly principal. An amortisation schedule shows this breakdown month by month.

Completion The final stage — when legal ownership transfers. Your solicitor sends funds to the seller, the seller vacates, and you receive keys. Your mortgage begins from this date.

Frequently Asked Questions

In the UK, the minimum deposit for a residential mortgage is typically 5% of the property price — giving you a 95% LTV mortgage. However, rates at 95% LTV are significantly higher than at 80% LTV. A 10% deposit opens up considerably more options and better rates. A 20% deposit (80% LTV) typically unlocks near-best-buy rates. First-time buyers may be eligible for the Mortgage Guarantee Scheme which supports 95% LTV mortgages. In the US, conventional mortgages require as little as 3% down (with PMI/private mortgage insurance); FHA loans allow 3.5% with lower credit scores.

UK lenders typically apply an income multiple to determine maximum borrowing — usually 4x to 4.5x your annual income (or combined income for joint mortgages). A household earning £60,000 per year might be able to borrow £240,000–£270,000. However, lenders also conduct an affordability assessment — they look at your outgoings, existing debts, childcare costs, and stress-test repayments at higher rates. The income multiple is a starting point; affordability assessment is the binding constraint. Getting a Mortgage in Principle from a broker gives you a personalised figure based on your actual circumstances.

A fixed rate mortgage locks your interest rate — and therefore your monthly payment — for a set period, typically 2, 3, or 5 years. Regardless of what the Bank of England does with rates, your payment stays the same. A variable rate mortgage (including trackers and discounted variable rates) moves with the Bank of England base rate or the lender's rate. If the BoE cuts, your payment falls; if it raises, your payment rises. Fixed rates provide certainty; variable rates provide flexibility and potential benefit from rate cuts, with the risk of rate rises. In 2025, with rates expected to fall, tracker mortgages are gaining popularity.

Yes — but check for Early Repayment Charges (ERCs) first. During a fixed or discounted rate period, most lenders allow overpayments of up to 10% of the outstanding balance per year without penalty. Overpaying beyond this, or repaying the entire mortgage during the deal period, triggers ERCs — typically 1–5% of the outstanding balance. Once the initial deal period ends and you're on the SVR, most mortgages allow unlimited overpayments or full repayment without penalty. If you want maximum flexibility, tracker or variable rate mortgages often have no ERCs.

Missing mortgage payments is serious but not immediately catastrophic. Contact your lender the moment you anticipate difficulty — most lenders have hardship teams and are legally required to treat customers in financial difficulty fairly. Options include: payment holidays (temporary pauses), switching to interest-only temporarily to reduce monthly payments, term extension, or a formal repayment plan. Lenders must exhaust these options before beginning repossession proceedings, which typically takes many months. The worst thing to do is ignore the problem — proactive communication with your lender almost always leads to a workable arrangement.

Important: All figures in this article are illustrative estimates for educational purposes. Mortgage rates, affordability criteria, and products change frequently. This article does not constitute mortgage advice. Always seek advice from a qualified, FCA-regulated mortgage adviser before making any mortgage decisions. WiseInvestorPath is not a regulated mortgage adviser. Read our full Disclaimer.