What is LTV (Loan to Value)?

LTV (Loan to Value) is the ratio of your mortgage loan to the property value, expressed as a percentage. For example, a 250,000 property with a 50,000 deposit gives an LTV of 80% (200,000 loan / 250,000 value). LTV is important because lenders offer better interest rates at lower LTV bands (typically below 90%, 80%, 75%, 60%). A higher deposit means a lower LTV and usually a cheaper mortgage rate.

What is the difference between repayment and interest-only mortgages?

A repayment mortgage (also called capital and interest) has monthly payments that cover both interest and some capital. At the end of the term, the loan is fully repaid. An interest-only mortgage has monthly payments that cover only the interest. The capital balance stays the same throughout and must be repaid in full at the end of the term (usually by selling the property or using a repayment vehicle like an ISA). Interest-only payments are lower but you still owe the full loan amount at the end.

How do I calculate how much I can borrow?

Most lenders use an income multiple of 4 to 4.5 times your gross annual income, or 3 to 4 times joint income. For example, with a 50,000 salary you might borrow 200,000 to 225,000. Lenders also conduct affordability assessments checking your monthly outgoings against your income at a stressed interest rate (typically 2-3% above current rates). Use this calculator to work backwards: enter your target monthly payment to see what loan size it corresponds to.

How does this mortgage calculator work?

Enter the property price, deposit, annual interest rate and term in years. The calculator instantly shows your monthly repayment, total interest, total amount paid, LTV and a full amortisation schedule. Add an overpayment amount to see how many years and how much interest you would save. Toggle interest-only mode for interest-only mortgages. Download the full schedule as CSV for use in spreadsheets.

Mortgage Calculator

Q: How is a monthly mortgage payment calculated?

The monthly mortgage payment M is calculated using the formula M = P * (r * (1+r)^n) / ((1+r)^n - 1), where P is the loan principal (property price minus deposit), r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments (loan term in years multiplied by 12). This is the standard repayment mortgage formula used by all major lenders.

Q: What is an amortisation schedule?

An amortisation schedule is a complete table showing every payment over the life of a mortgage. Each row shows the month, payment amount, how much of that payment goes to principal, how much goes to interest, and the remaining balance. In the early years of a mortgage most of each payment is interest with very little principal repaid. As the balance decreases, the interest portion shrinks and more of each payment reduces the principal.

Q: How much do overpayments save?

Overpayments reduce the outstanding balance faster, meaning less interest accrues each month. For example, on a 25-year mortgage at 5%, overpaying by 200 per month typically saves over 3 years of payments and tens of thousands in interest. Use the overpayment field in this calculator to see the exact impact for your mortgage. The years saved and interest saved are shown automatically.

Q: Free mortgage calculator with amortisation schedule

Yes. This mortgage calculator shows the full amortisation schedule month-by-month or year-by-year for the entire mortgage term, free with no account required. Toggle between yearly summary and all monthly rows. Download the complete schedule as a CSV file for use in Excel or Google Sheets. The overpayment simulator shows exactly how much time and interest you save by paying extra each month.

Key Features

What This Mortgage Calculator Shows

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Full amortisation schedule downloadable as CSV — rare on free tools — The complete month-by-month amortisation table shows every payment split into principal and interest, with the remaining balance. Toggle between yearly summary view and all monthly rows. Download the entire schedule as a CSV file for use in Excel or Google Sheets — a feature absent or paywalled on most competing tools.

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Overpayment simulator — shows exact years saved and interest saved — Enter a monthly overpayment amount and instantly see how many years and months come off your mortgage term, and exactly how much total interest you save. The amortisation schedule and chart update in real time to reflect the overpayment. This feature is typically locked behind paywalls on major mortgage sites.

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Annual stacked bar chart — visualise principal vs interest by year — The interactive SVG chart shows how your annual payments split between principal (indigo) and interest (pink) for every year of the mortgage. In the early years, interest dominates. As the balance falls, the principal share grows. The chart updates instantly with every change in rate, term or overpayment.

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Interest-only mortgage toggle — Switch between repayment and interest-only mode. In interest-only mode, the monthly payment covers only the interest and the full loan balance remains at the end of the term. Essential for buy-to-let landlords, bridging finance calculations and interest-only product comparisons.

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7 currencies and live recalculation — Supports GBP, USD, EUR, INR, AED, AUD and CAD. All results update in real time as you type — no calculate button to press. The currency symbol updates throughout all displayed values instantly when changed.

How To Use

How to Calculate Your Mortgage

Enter property price and deposit — The loan amount (principal) is calculated automatically. LTV ratio is shown in the summary. Adjust the currency if needed.

Set rate and term — Enter your annual interest rate (e.g. 5 for 5%) and mortgage term in years. Results update instantly as you type each digit.

Add overpayment (optional) — Enter a monthly overpayment amount to see the years saved and interest saved. The green savings box appears automatically. The amortisation schedule shortens to reflect the faster payoff.

Download the schedule — Click Download CSV to export the full month-by-month amortisation table. Toggle between yearly summary and all monthly rows using the table view button.

Comparison

LazyTools vs Other Mortgage Calculators

Feature	LazyTools	MoneySavingExpert	Bankrate	NatWest
Monthly repayment	✅ Yes	✅ Yes	✅ Yes	✅ Yes
Full amortisation schedule	✅ Yes	⚠ Partial	✅ Yes	❌ No
Download CSV	✅ Yes	❌ No	❌ No	❌ No
Overpayment simulator	✅ Yes (exact savings)	✅ Yes	⚠ Limited	❌ No
Interest-only toggle	✅ Yes	✅ Yes	✅ Yes	⚠ Separate tool
Live recalculation (no button)	✅ Yes	❌ Button	❌ Button	❌ Button
No account required	✅ Yes	✅ Yes	✅ Yes	⚠ Partial
No ads / tracking	✅ Yes	❌ Many ads	❌ Many ads	❌ Tracking

Reference

Monthly Payment Reference — Common Loan Sizes

Loan amount	At 4%	At 5%	At 6%	At 7%
£100,000 / 25yr	£528	£585	£644	£707
£200,000 / 25yr	£1,056	£1,170	£1,289	£1,413
£300,000 / 25yr	£1,583	£1,754	£1,933	£2,120
£400,000 / 25yr	£2,111	£2,339	£2,577	£2,827
£500,000 / 25yr	£2,639	£2,924	£3,222	£3,533

Guide

Mortgage Calculator — Understanding Monthly Payments, Amortisation and Overpayments

How the monthly payment formula works

The monthly mortgage payment M is calculated using the amortisation formula: M = P × (r(1+r)^n) / ((1+r)^n − 1), where P is the loan principal, r is the monthly interest rate (annual rate / 12) and n is the total number of payments (years × 12). In the early months of a mortgage almost all of each payment goes to interest because the balance is large and interest accrues on the full amount. As each payment reduces the balance slightly, a little more of the next payment goes to principal. This snowball effect accelerates toward the end of the term.

Why overpayments are so powerful

Every overpayment directly reduces the outstanding balance. Because future interest is calculated on the reduced balance, less interest accrues from that point forward. Paying an extra £200 per month on a £270,000 mortgage at 5% over 25 years typically saves over 4 years of payments and around £30,000 in total interest. The savings are non-linear: overpayments made early in the mortgage save significantly more than the same overpayments made late, because they reduce the balance during the high-interest early years.

Understanding LTV bands and interest rates

LTV (Loan to Value) is the ratio of your mortgage to the property value. Lenders price mortgages in LTV bands: below 95%, 90%, 85%, 80%, 75%, 70% and 60% are common thresholds. A lower LTV means less risk for the lender and typically a better interest rate. Dropping from 90% to 80% LTV (by saving a larger deposit) can reduce your rate by 0.2–0.5%, which on a £250,000 mortgage saves tens of pounds per month and thousands over the mortgage term.

Interest-only vs repayment mortgages

A repayment mortgage (capital and interest) reduces your loan balance with every payment. After the full term, the debt is cleared. An interest-only mortgage has lower monthly payments — you only pay the interest on the loan, never the capital. The balance remains identical throughout the entire term and must be repaid in full when the mortgage ends. This is typically done by selling the property, using savings or a pension. Interest-only is common in buy-to-let investment where rental yield covers the interest and capital growth provides the exit.

FAQ

Frequently Asked Questions

How is a monthly mortgage payment calculated?▾

Monthly payment M = P × (r(1+r)^n) / ((1+r)^n − 1), where P = loan principal, r = monthly rate (annual rate / 12), n = total months (years × 12). This calculator applies this formula and shows every payment split month by month in the amortisation schedule.

What is an amortisation schedule?▾

A table showing every payment over the mortgage term. Each row shows: payment amount, how much goes to principal, how much to interest, and the remaining balance. In early years interest dominates. As the balance falls, more of each payment reduces the principal. Toggle monthly or yearly view above, or download as CSV.

How much do overpayments save?▾

Overpayments reduce the balance faster, lowering future interest accrual. For a £270k mortgage at 5%, paying £200/month extra saves around 4 years and £30,000 in interest. Enter your overpayment amount to see the exact saving for your mortgage — the green box shows years saved and interest saved automatically.

What is LTV and why does it matter?▾

LTV (Loan to Value) = loan amount / property value. At 80% LTV on a £300k property: £240k loan. Lenders offer better rates at lower LTV bands (90%, 85%, 80%, 75%, 60%). A higher deposit reduces LTV and usually lowers your interest rate, saving significantly over the mortgage term.

What is interest-only vs repayment?▾

Repayment: monthly payment covers interest plus some capital. Loan fully repaid at end of term. Interest-only: monthly payment covers only interest. Capital balance stays the same and must be repaid at term end (by selling, savings or pension). Use the interest-only toggle to compare both for your numbers.

Free mortgage calculator with amortisation schedule▾

Yes — enter your mortgage details and the full amortisation schedule appears instantly with monthly breakdown. Toggle between yearly summary and all monthly rows. Download the complete schedule as CSV. Overpayment simulator included. Interest-only toggle. 7 currencies. Free, no account, no data sent to any server.

Mortgage overpayment savings calculator▾

Enter your property price, deposit, rate and term. Then enter a monthly overpayment amount. The green Overpayment savings box shows exactly how many years and months you save, and how much total interest you save compared to making no overpayments. The amortisation schedule updates automatically to show the shorter term.

How much can I borrow for a mortgage?▾

Most lenders use 4 to 4.5 times gross annual income as a maximum loan size. For a £50,000 salary: up to £225,000 loan. Joint applicants: typically 3 to 4 times combined income. Lenders also run affordability assessments at stressed rates. Use this calculator to find the monthly payment for your target loan size and see if it fits your budget.

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