Second & Third Charge Loan Calculator
For loans secured behind an existing mortgage (or an existing second charge): see the combined LTV across all charges, the new loan's monthly cost, and total cost including typical secured-loan fees.
Property & existing charges
New charge requested
Rental coverage (buy-to-let)
Combined LTV
Current combined LTV
45.0%
Proposed combined LTV
55.0%
Equity now
£220,000
Equity after new charge
£180,000
| Charge | Balance | Cumulative | Cumulative LTV |
|---|---|---|---|
| 1st charge (existing mortgage) | £180,000 | £180,000 | 45.0% |
| + New charge | £40,000 | £220,000 | 55.0% |
New charge cost
Monthly payment
£260
Total interest
£15,600
Total fees
£1,500
Total cost of borrowing
£17,100
Generic maths only — not specific to any lender's criteria, product or APRC. Second/third charge lending criteria (maximum combined LTV, consent from the prior charge holder, etc.) vary by lender. Always confirm with the lender's own illustration.
How this works
A second (or third) charge loan sits behind one or more existing charges secured on the same property. What matters for LTV purposes is the combined balance of everything secured against the property, not just the new loan — so the combined LTV builds up charge by charge, and lenders typically cap the maximum combined LTV they'll allow behind an existing charge.
Frequently asked questions
- What's the difference between a second charge and remortgaging?
- A second charge loan sits alongside your existing first-charge mortgage rather than replacing it — useful when the existing mortgage has an attractive rate or early repayment charges that make remortgaging unattractive.
- Can you have a third charge?
- Yes — this calculator supports any number of existing charges. Third charges are less common and typically only available from a smaller pool of specialist lenders.
- Does the existing lender need to consent?
- Usually yes — the first-charge lender typically needs to provide consent (a Deed of Postponement or similar) before a second charge can be registered.
- For a BTL 2nd charge, is rental coverage checked against just the new payment?
- No — rent has to service the combined cost of the existing 1st charge plus the new 2nd charge, which is what the rental coverage section above checks, rather than looking at the 2nd charge payment in isolation.
Want the full picture? Open the full Mortgage Case Calculator →