Combined Loan-to-Value Calculator

What this calculator is, and when to reach for it

Most people know roughly what their mortgage represents as a share of their home’s value. Far fewer know what all their property-secured borrowing represents, and that second figure is the one lenders actually use. Combined loan-to-value adds up every loan secured on the property and divides the total by the value, which is why a borrower who feels comfortably positioned can be declined for reasons that seem to come from nowhere.

The gap between the two figures can be substantial. A first mortgage at 70% of value looks healthy. Add a home equity loan of another 10% and the combined figure is 80%, sitting right on the boundary where many lenders stop. Nothing about the first mortgage changed; the assessment did.

This matters most at the moment you want to borrow again — a second charge, a credit line, or a remortgage. Lenders are not asking how exposed your first loan is; they are asking how much of the property is already claimed and how much cushion remains if prices fall. Every charge counts toward that, in the order they would be repaid.

Reach for this page before applying for any additional secured borrowing, when you are working out how much of a credit line you can realistically request, or when a lender’s decision has not matched what your first mortgage alone would suggest.

Why the order of the loans matters

Secured loans rank. The first charge is repaid first from any sale, the second charge only from what remains, and so on. That ranking is the whole reason second-charge lending is priced higher: the lender behind is the one who absorbs a shortfall.

It also explains why the combined figure carries more weight than any individual loan. A second-charge lender at a combined 85% is exposed to the last 15% of the property’s value and nothing more, which is a far riskier slice than the first lender’s position even though both are secured on the same home.

For you as the borrower, the practical consequence is that adding a small second loan can move you into a materially worse pricing band for anything you do afterwards, including remortgaging the first loan.

Where to go next

For the first mortgage on its own, use the loan to value calculator, and to see the same position expressed as an amount you own, the home equity calculator.

If you are considering the borrowing that would raise this ratio, the home equity loan calculator covers a fixed lump sum, the HELOC calculator covers a revolving line, and the cash-out refinance calculator covers replacing the mortgage with a larger one instead of adding a second charge.

To bring the ratio down rather than up, the extra payment calculator and the amortization calculator show how quickly repayment moves you. If better pricing is the goal, the refinance calculator tests whether acting on an improved ratio is worth the cost.

How the combined ratio is worked out

One division, with a numerator that has to be assembled carefully. Most errors on this page are omissions rather than arithmetic.

CLTV = ((first mortgage + additional secured debt) ÷ property value) × 100

first mortgage

the balance outstanding on the primary loan

additional secured debt

every other loan secured on the property, including drawn credit lines

property value

the lender’s valuation, not an owner’s estimate

Drawn balance or full limit?

For a credit line the distinction matters. Your combined ratio today reflects what you have actually drawn, since that is the debt in existence. But many lenders assessing new borrowing will count the full available limit, on the reasoning that you could draw it tomorrow.

This produces two legitimate figures that differ, and it catches people out. An undrawn facility can be invisible in your own calculation and decisive in a lender’s. If you are applying for further borrowing and hold an unused line, either expect it to be counted or close it first.

What belongs in the numerator

Include the first mortgage, any second charge, home equity loans, drawn credit lines, and any other borrowing registered against the property. Include charges held by anyone, not only mainstream lenders.

Exclude everything unsecured: cards, personal loans, car finance, and student debt. Those matter enormously to affordability and appear in debt-to-income, but they have no claim on the property and no place in this ratio.

Where the caps usually sit

Lenders typically allow total secured borrowing up to somewhere between 80% and 85% of value, with the exact figure varying by lender, product, and country. Some specialist lenders go higher at considerably worse pricing.

The cap is what determines how much additional borrowing is available: apply it to the value and subtract what you already owe. That subtraction is why a modest fall in value or a small existing second charge can eliminate borrowing capacity that appeared comfortable.

Why this ratio moves against you faster

The combined figure responds to changes in value the same way the simple ratio does, but with a larger balance on top it starts closer to the caps, so the same percentage fall in value pushes it across a threshold sooner.

A household at 70% on the first loan alone has substantial room before any cap. The same household at 80% combined has almost none. Adding secured debt does not just raise a number; it removes the buffer that protects you from the market.

What this page assumes

This calculator adds first-mortgage and additional outstanding secured debt, then divides the total by property value.

It accepts zero and above-100% ratios but does not predict lender eligibility.

Worked examples, step by step

Take a property valued at 400,000 with a first mortgage of 280,000 and a home equity loan of 40,000 secured behind it.

The first loan alone against everything together

On the first mortgage alone this borrower sits at a comfortable 70%, well inside most lenders’ appetite. Counting both loans, they are at 80% — precisely on the boundary where many lenders stop and where mortgage insurance considerations begin.

The consequence is immediate: at an 85% cap there is 20,000 of further borrowing available; at an 80% cap there is none at all. A borrower who assessed themselves on the first mortgage would have expected roughly 60,000 to be available and would be surprised twice over.

What a small fall in value does

Suppose the valuation comes back at 380,000 rather than 400,000, a 5% difference well within the range of surveyor disagreement. The combined ratio moves from 80.0% to 84.2%, and equity falls from 80,000 to 60,000.

At an 85% cap, available borrowing collapses from 20,000 to 3,000. A five percent movement in one input removed 85% of the borrowing capacity, which is why applications built on an optimistic valuation so often fail at the survey stage rather than the affordability stage.

The vocabulary, on and around this page

Combined loan to value

Every loan secured on a property, added together and expressed as a percentage of its value. The figure lenders assess for additional borrowing.

Loan to value

The same ratio for a single loan, usually the first mortgage. It can look comfortable while the combined figure does not.

First charge

The loan repaid first from any sale, normally the main mortgage. Its priority is why it is priced most keenly.

Second charge

A loan ranking behind the first, repaid only from what remains. The extra risk is why it carries a higher rate.

Ranking

The order in which secured lenders are repaid from a sale. It determines who absorbs a shortfall and therefore how each loan is priced.

Secured debt

Borrowing that uses the property as security. Only secured debt belongs in this ratio.

Unsecured debt

Borrowing with no claim on the property, such as cards or personal loans. It affects affordability but never this ratio.

Drawn balance

The amount actually taken from a credit line. It is what your current ratio reflects.

Available limit

The full amount a credit line permits. Many lenders count this rather than the drawn balance when assessing new borrowing.

Lender cap

The maximum combined ratio a lender will allow, commonly between 80% and 85%. It determines remaining borrowing capacity.

Borrowing capacity

The cap applied to the value, less what is already secured. It falls faster than equity when values move.

Equity

Value less all secured debt. It is the same position as the combined ratio, expressed as an amount.

Home equity loan

A lump sum secured as a second charge and repaid on a fixed schedule. It raises the combined ratio immediately.

Home equity line of credit

A revolving secured facility. Only drawn amounts are debt, but the limit may still be assessed against you.

Cash-out refinance

Replacing the first mortgage with a larger one instead of adding a second charge. It keeps a single loan but raises the ratio.

Valuation

The lender’s assessment of value, and the only figure that counts. Small differences move this ratio noticeably.

Subordination

An agreement allowing a loan to move behind another in ranking, often needed when refinancing a first mortgage that sits above a second charge.

Negative equity

A combined ratio above 100%, meaning secured debt exceeds value. It removes further borrowing entirely.

Mortgage insurance

A premium applied above certain ratios. The combined figure, not the first mortgage alone, is often what triggers it.

Threshold

A boundary between pricing bands. Adding secured debt can cross one and worsen terms on future borrowing.

Common mistakes, and what this page will not do

• Assessing yourself on the first mortgage alone. A comfortable 70% on the main loan became 80% combined in the example, which is the difference between having borrowing capacity and having none.
• Forgetting an undrawn credit line. Your own figure reflects what you have drawn, but many lenders count the full available limit when assessing new borrowing.
• Including unsecured debts. Cards, personal loans, and car finance belong in debt-to-income, not here. Only borrowing secured on the property counts.
• Using an optimistic valuation. A 5% difference moved the ratio from 80.0% to 84.2% and cut available borrowing by 85% in the worked example.
• Assuming a small second loan is harmless. It can cross a pricing threshold and worsen terms on everything afterwards, including remortgaging the first loan.
• Ignoring how ranking affects pricing. A second-charge lender is exposed to only the last slice of value, which is why the rate is higher regardless of your record.
• Overlooking subordination when refinancing. Replacing a first mortgage that sits above a second charge usually needs the second lender’s agreement to stay behind. It is not automatic.
• Treating the cap as a target. Borrowing to a lender’s maximum removes the buffer that protects you from a fall in value, and capacity moves faster than equity.
• Assuming caps are the same everywhere. They vary by lender, product, and country. A figure that works with one lender may be outside another’s appetite entirely.

What this calculator leaves out: This calculator adds the secured balances you enter and divides by the value you enter. It does not produce or verify a valuation, apply any specific lender’s caps or overlays, decide whether a credit limit or drawn balance should be counted, assess affordability or credit, or determine eligibility. It accepts ratios above 100%.

Frequently asked questions