The two limits that decide what you can borrow
Secured loan lenders apply two separate caps and lend whichever is lower:
- Equity cap (LTV). A maximum percentage of your property value, including your existing mortgage. This protects the lender if your home has to be sold.
- Affordability cap. A monthly payment you can demonstrably afford from your income, after your existing commitments. This protects you (and the lender) from over-borrowing.
Both have to be satisfied. Plenty of equity but stretched income? Affordability cap kicks in. Comfortable income but already 80% mortgaged? Equity cap kicks in.
How LTV is calculated
Combined LTV = (existing mortgage + new secured loan) ÷ property value.
Example: a £300,000 home with a £150,000 mortgage. At an 85% combined LTV cap, total secured borrowing can be £255,000. Subtract the existing mortgage and your maximum secured loan is £105,000.
| Credit profile | Typical max LTV |
|---|---|
| Excellent (no adverse) | 85–90% |
| Good (minor issues) | 85% |
| Fair (some adverse) | 80% |
| Poor (significant adverse) | 70–75% |
Worked examples
| Property value | Existing mortgage | 85% combined LTV ceiling | Max secured loan |
|---|---|---|---|
| £200,000 | £100,000 | £170,000 | £70,000 |
| £300,000 | £150,000 | £255,000 | £105,000 |
| £500,000 | £200,000 | £425,000 | £225,000 |
| £500,000 | £0 (mortgage-free) | £425,000 | £425,000 |
These figures are the equity cap only — your actual borrowing also has to clear the affordability check.
The affordability check
Lenders model your monthly net income against your committed outgoings — existing mortgage, credit cards, personal loans, car finance, child maintenance, regular subscriptions — plus the new secured loan payment, often stress-tested at a higher rate (usually +1–3%).
As a rough guide, total secured borrowing is typically capped at 4–4.5× household income. Some specialist lenders use bespoke calculations and can go higher for high-earners or applicants with low fixed outgoings.
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