The question most borrowers ask before anything else is “how much can I actually borrow?” For a secured loan, the answer depends on two independent limits: the equity available in the property and the amount the borrower can afford to repay each month. The effective maximum is whichever of those two figures is lower, but most borrowers do not know which one is constraining them, and no existing tool calculates both in one place.
This tool takes both sides of the equation, property value and mortgage balance on the equity side, income and commitments on the affordability side, and calculates the estimated borrowing power. It shows which constraint is binding, how the maximum changes across LTV tiers and at different illustrative rates, and what would need to change to reach a higher target. All figures are illustrative and the tool does not constitute financial advice.
At a Glance
-
Borrowing power is the lower of two limits. Most borrowers only check one.
Second charge lenders assess both the equity position (how much the property can support) and the affordability position (how much the borrower can repay). The effective borrowing ceiling is whichever is lower. A borrower with £70,000 of equity headroom but income that supports only £35,000 of repayment has a borrowing power of £35,000, not £70,000. This tool calculates both limits simultaneously and identifies which one is binding.
-
The LTV staircase shows where affordability overrides equity at higher tiers.
Equity headroom increases at each LTV tier (70%, 75%, 80%, 85%), but the affordability ceiling does not change because it depends on income and commitments, not property value. At some point as LTV increases, the equity headroom exceeds what affordability supports. The staircase makes this crossover visible: green tiers are fully accessible, amber tiers are capped by affordability. Knowing which tier the crossover occurs at helps a broker match the application to the right lender.
-
The rate you are offered changes how much you can borrow, not just what it costs.
A higher APR means a higher monthly payment per pound borrowed, which reduces the affordability ceiling. The rate sensitivity panel shows the effective maximum at three illustrative rates so the borrower can see how improving their credit profile or LTV position, which typically unlocks a lower rate, increases borrowing power as well as reducing cost. This is one of the strongest practical arguments for preparation before applying.
-
If the maximum falls short of what you need, the diagnostic shows three routes to close the gap.
Enter a target amount above the estimated maximum and the tool shows three specific actions: reduce the mortgage by a stated amount (equity route), clear a stated amount of monthly commitments (affordability route), or extend the term by a stated number of years (payment route). Each route shows the exact figure required, turning a shortfall into an actionable plan rather than a dead end.
Interactive tool
Secured loan borrowing power calculator
Estimate how much you could borrow as a secured loan based on your equity position and affordability. The effective maximum is the lower of the two limits.
All figures are illustrative. Nothing you enter is stored or transmitted.
Your property
Your income and commitments
Before tax. Include second applicant if joint.
Cards, loans, car finance, student loan combined
Proposed loan
Estimated borrowing power
–
–
Maximum at each LTV tier (equity headroom vs affordability ceiling)
How the illustrative APR affects borrowing power
Need more? Enter a target amount
Set above your estimated maximum to see how to bridge the gap.
How to reach your target
–
Borrowing power estimates use a 40% DTI threshold as a broad approximation of typical lender appetite. Individual lenders apply their own affordability models which may produce higher or lower figures. Equity headroom is calculated at each combined LTV tier assuming the mortgage balance entered is the only existing charge. The rate sensitivity panel uses illustrative APR figures and does not represent rates available from any specific lender. This tool does not constitute financial advice. All figures are illustrative only.
About this tool
What it calculates
Equity ceiling, affordability ceiling, and effective borrowing power
Enter property value, mortgage balance, income, commitments, and a proposed term and rate. The tool calculates the equity headroom at each LTV tier, the maximum supportable borrowing from the affordability position, and the effective borrowing power as the lower of the two. The binding constraint is labelled explicitly so the borrower knows which factor is limiting them.
Key features
LTV staircase, rate sensitivity, and gap-closing diagnostic
The LTV staircase shows the effective maximum at four tiers with the affordability overlay. The rate sensitivity panel shows how borrowing power changes at three illustrative APR levels. The target slider activates a diagnostic that shows three specific routes to reach a higher amount: reducing the mortgage, clearing commitments, or extending the term.
How to use the borrowing power calculator
The tool works in two phases. The first phase takes the property and income inputs and calculates the borrowing power. The second phase, activated by the target slider, shows what would need to change to borrow more. The most useful exercise is to run the first phase with accurate figures, note which constraint is binding, and then use the target slider to explore whether the shortfall (if any) is closeable before applying.
Enter your property value and mortgage balance
Use the property value slider to set the current market value of the property you would secure the loan against. Use a recent Zoopla or Rightmove estimate if you do not have a formal valuation. The mortgage balance is the outstanding amount on the existing first charge. The tool uses these two figures to calculate the equity headroom at each LTV tier. If the property has an existing secured loan or other charge, add that balance to the mortgage figure.
Enter your income and monthly commitments
Set your gross monthly income (before tax), your monthly mortgage payment, and your other monthly debt commitments (credit cards, loans, car finance, student loan combined). The tool uses these to calculate the maximum additional monthly payment that keeps total debt commitments within a 40% DTI threshold, which is a broad approximation of typical lender appetite. The monthly affordability checker provides a more detailed stress-test once you have a specific amount in mind.
Set the proposed term and illustrative APR
The term and APR determine the monthly payment per pound borrowed, which directly affects the affordability ceiling. A longer term reduces the monthly cost and increases borrowing power. A lower APR does the same. The rate sensitivity panel below the main result shows how the effective maximum changes at the selected rate plus and minus two percentage points, making the impact of credit profile on borrowing power visible. The APR band cost comparator shows how different rate tiers translate to total cost.
Review the result, then use the target slider if needed
The main result shows the estimated borrowing power with the binding constraint labelled. The LTV staircase and rate sensitivity panels provide additional context. If the maximum is below what you need, set the target slider to your desired amount and the diagnostic panel shows three specific routes to close the gap: reducing the mortgage, clearing monthly commitments, or extending the term. Each route shows the exact figure required so you can assess which is most practical before applying.
How the dual-constraint calculation works
A second charge mortgage is secured against a property that already has a first charge (the existing mortgage). The lender needs to be confident of two things: that the combined secured debt does not exceed a safe proportion of the property value (the LTV constraint), and that the borrower can afford the monthly payment on top of their existing commitments (the affordability constraint). Both must be satisfied for the loan to proceed. If either one fails, the application is declined or the amount is reduced.
The equity ceiling is calculated by taking the property value, multiplying by the LTV threshold (typically 70% to 85% depending on the lender), and subtracting the outstanding mortgage balance. The result is the maximum additional borrowing the property can support at that LTV level. The affordability ceiling is calculated by working backwards from the maximum monthly payment the borrower can sustain within a 40% DTI threshold: gross monthly income multiplied by 0.40, minus the mortgage payment and other commitments, gives the available monthly budget, and the inverse amortisation formula converts that payment into a maximum loan amount at the given rate and term. The effective borrowing power is whichever ceiling is lower. The guide to what secured loan lenders look for explains how these two assessments fit into the broader underwriting process.
Understanding the LTV staircase
Different lenders operate at different maximum combined LTV thresholds. Mainstream second charge providers typically cap at 75% to 80% combined LTV. Specialist lenders may extend to 85% or occasionally higher, often at a higher rate to reflect the additional risk. The staircase shows the equity headroom at four common thresholds (70%, 75%, 80%, 85%) alongside the affordability ceiling, so the borrower can see at which tier the constraint switches from equity to affordability.
A tier marked green means the full equity headroom at that LTV is accessible given the affordability position. A tier marked amber means the equity headroom exceeds what affordability supports, so the effective maximum at that tier is capped by income rather than equity. A greyed-out tier means the existing mortgage already exceeds that LTV threshold, so no additional borrowing is available at that level regardless of affordability. The LTV and equity calculator provides a more detailed breakdown of the equity position across all tiers, and the guide to understanding LTV ratios explains how lenders use these thresholds in pricing and eligibility decisions.
How rate affects borrowing power
The illustrative APR directly affects the affordability ceiling because it determines the monthly payment per pound borrowed. A higher rate means a higher monthly cost for the same loan amount, which reduces the maximum borrowing that the available monthly budget can support. The rate sensitivity panel shows this by calculating the effective borrowing power at three rates: the selected rate minus two percentage points, the selected rate, and the selected rate plus two percentage points.
This has a practical implication for preparation. A borrower who improves their credit profile (which typically moves the offered rate down by one or two tiers), reduces their LTV (which also unlocks better pricing), or applies through a broker who can access more competitive specialist rates, may find that the lower rate increases their borrowing power by several thousand pounds beyond the rate saving itself. The credit profile classifier maps the borrower’s credit position to lender tiers and indicative rate bands, and the guide to secured loans for bad credit covers how adverse credit affects both rate and borrowing capacity.
The “how to borrow more” diagnostic
When the estimated maximum falls short of the amount needed, the diagnostic shows three routes to close the gap. The equity route calculates the mortgage reduction required to bring the equity ceiling up to the target at 80% LTV. The affordability route calculates the monthly commitment reduction required to free enough budget headroom. The term route identifies the shortest extended term that would bring the target within reach at the current rate and equity position. Each route shows the exact figure needed, which turns a “you cannot borrow that much” result into a specific action plan.
In practice, the most accessible route depends on the borrower’s circumstances. Clearing high-rate unsecured debt before applying is often the fastest way to increase the affordability ceiling, because every pound of monthly commitment cleared translates directly into additional borrowing capacity. Extending the term is the simplest change but increases total interest paid. Reducing the mortgage balance typically takes the longest but has the additional benefit of improving the LTV for the next remortgage. A broker can advise on which route is most practical for a given situation. The step-by-step application guide covers the preparation that maximises the chance of approval at the amount needed.
Related tools
Equity
LTV and equity calculator
For a deeper view of the equity position, including the maximum at every LTV tier and a built-in repayment modeller for the selected amount. Use it after the borrowing power calculator to model the exact cost of the amount you plan to request. Use the tool
Pre-application
Credit profile classifier
The rate you are offered depends heavily on your credit profile. This tool maps your credit position to four lender tiers and shows the indicative rate band for each, which feeds directly into the rate sensitivity calculation in the borrowing power tool. Use the tool
Looking for more loan resources?
Guides and tools covering secured loans, debt consolidation, and home improvementsFrequently asked questions
Why does the tool use a 40% DTI threshold for the affordability ceiling?
The 40% figure is a broad approximation of the DTI level at which most UK secured loan lenders will consider an application without requiring exceptional compensating factors. It is not a rule: some lenders accept higher DTI ratios (particularly specialist providers), and some apply stricter thresholds. The tool uses 40% as a modelling assumption to produce a realistic estimate of borrowing power across the mainstream and specialist market. The actual ceiling a specific lender applies may be higher or lower depending on credit profile, LTV, income stability, and the lender’s own criteria.
For a more detailed view of how DTI affects lender appetite, the debt-to-income ratio calculator maps the ratio to four lender tiers and shows which debts contribute most to the figure. Using both tools together provides a more complete pre-application picture than either one alone: the borrowing power calculator shows the maximum, and the DTI calculator shows how the overall ratio is structured.
What combined LTV can I actually get in the UK second charge market?
The combined LTV threshold varies by lender and by the borrower’s profile. Mainstream second charge providers typically cap at 75% to 80% combined LTV for borrowers with clean credit and standard income evidence. Specialist lenders may extend to 85% or occasionally 90%, particularly for borrowers with strong income and a clear purpose such as home improvements or debt consolidation. Higher LTV tiers typically carry higher rates because the lender has less equity protection.
The LTV staircase in the tool shows the effective maximum at 70%, 75%, 80%, and 85% so the borrower can see the range of outcomes. In practice, the LTV a specific lender will offer depends on the property type, the borrower’s credit and income profile, the purpose of the loan, and the lender’s current appetite. A broker with access to the specialist second charge market can identify which lenders are lending at higher LTV tiers for a given profile, which is one of the main reasons using a broker is more efficient than approaching lenders directly for secured loans.
How does extending the term increase borrowing power?
A longer term spreads the loan repayment over more months, which reduces the monthly payment for any given loan amount. Since the affordability ceiling is calculated from the maximum monthly payment the borrower can sustain, a lower payment per pound borrowed means more pounds can be borrowed before the ceiling is reached. For example, at 7% APR, a monthly budget of £300 supports approximately £25,800 over 10 years but approximately £38,700 over 20 years. The borrowing power increases by nearly 50% simply by extending the term.
The trade-off is total interest. The same loan at the same rate costs significantly more over 20 years than over 10 years because interest accrues for twice as long. The diagnostic in the tool shows the extended term required to reach the target, and the secured loan calculator can model the exact cost at that longer term so the borrower can see the total interest trade-off before committing. Choosing the shortest affordable term is generally the lower-cost approach, but extending the term may be the most practical route when the alternative is not borrowing at all.
Can clearing existing debts really increase how much I can borrow?
Yes, directly and measurably. Every pound of monthly debt commitment that is cleared before applying becomes a pound of monthly budget available for the new loan payment. The inverse amortisation formula then converts that freed budget into a borrowing figure. Clearing £150 per month of credit card payments, for example, frees £150 per month for the new loan. At 7% APR over 10 years, that £150 per month supports approximately £12,900 of additional borrowing. The diagnostic in the tool quantifies this: it shows the exact monthly commitment reduction needed to reach a stated target.
This is why debt consolidation is one of the most common uses of second charge lending. Replacing scattered high-rate debts with a single lower-rate secured loan reduces the total monthly commitment, which both improves affordability for the consolidated loan itself and frees capacity for future borrowing if needed. The debt consolidation saving and true cost calculator models the full cost and saving of this approach.
Is the estimated maximum what a lender will actually offer me?
No. The tool produces an illustrative estimate based on simplified assumptions about DTI thresholds and LTV caps. A lender’s actual affordability assessment is more detailed: it includes a full income verification, stress-testing at a higher rate, a review of the credit file, and an assessment of the specific property. The figure this tool produces is a directional guide, not a guarantee or a pre-approval. It is designed to give the borrower a realistic sense of the range before approaching a lender or broker, so the application can be directed to products and lenders whose criteria are likely to match.
The most accurate way to confirm borrowing power is through a Decision in Principle (DIP) from a lender, which involves a soft credit check and a formal affordability calculation. A broker can arrange DIPs from multiple lenders to establish the actual ceiling, and the figures from this tool provide a useful starting point for that conversation. The guide to how to apply for a secured loan covers the full process from initial assessment through to completion.
Squaring Up
Secured loan borrowing power is determined by two independent constraints: the equity the property can support and the monthly payment the borrower can afford. Knowing both figures, and which one is binding, is the most useful pre-application preparation a borrower can do. It focuses the conversation with a broker on the right dimension: improving equity if the property is the limit, or clearing commitments and adjusting the term if affordability is the limit.
The rate sensitivity and diagnostic features add two layers that no other tool provides. The rate panel shows that borrowing power is not fixed: improving the credit profile or LTV to unlock a lower rate increases what can be borrowed as well as reducing the cost. The diagnostic turns a shortfall into a plan, showing the exact changes needed to reach a specific target. Together, these features make the tool useful before and during the application process, not just as a first estimate.
Explore all loan guides and tools
Everything in one place, across secured loans, debt consolidation, and home improvementsThis tool is for illustrative purposes only and does not constitute financial advice. The 40% DTI threshold is a modelling assumption and does not represent the criteria of any specific lender. Individual lenders apply their own affordability models, stress tests, and LTV caps. The effective maximum shown is an estimate and may differ from the amount a lender would actually offer after a full affordability assessment and credit check. Your home may be at risk if you do not keep up repayments on a secured loan. Actual outcomes will depend on your individual circumstances.
