Second Mortgage Payment Calculator
Payment Breakdown
Monthly Payment-
First Month Interest-
First Month Capital-
Total Interest Over Term-
Total Cost (incl. fees)-
Amortisation Example — £40,000 at 6% Over 10 Years
| Year | Opening | Interest | Capital | Closing |
|---|---|---|---|---|
| 1 | £40,000 | £2,326 | £2,999 | £37,001 |
| 2 | £37,001 | £2,139 | £3,186 | £33,815 |
| 5 | £23,820 | £1,316 | £4,009 | £19,811 |
| 8 | £10,850 | £522 | £4,803 | £6,047 |
| 10 | £2,575 | £81 | £5,244 | £0 |
Capital repayments increase each year as the outstanding balance and interest portion reduces.
Payment Split Over Time
Year 1 Interest
44%
Year 5 Interest
25%
Year 10 Interest
2%
Arrangement Fee
£500–£1,500
Valuation Fee
£150–£500
Legal Fees
£500–£1,000
How to Use This Calculator
1
Enter your loan amount
Input the total second mortgage amount excluding any fees.
2
Set the interest rate
Enter the annual rate. Second charge mortgages typically carry rates of 4.5-8%.
3
Choose your term
Select repayment period in years. Shorter terms cost less total interest.
4
Add arrangement fees
Include lender arrangement or product fees to see the true total cost.
5
Review the breakdown
See how payments split between capital and interest and the full cost including fees.
Frequently Asked Questions
How is the payment calculated?
Using the standard annuity formula: monthly = P x [r(1+r)^n] / [(1+r)^n - 1]. Early payments are mostly interest; later ones mostly capital.
What affects my monthly payment?
Three factors: loan amount, interest rate and term length. Higher loans or rates increase payments; longer terms reduce them but cost more total interest.
Can I make overpayments?
Most lenders allow 10% per year without charges. Overpayments reduce total interest and shorten the term. Check your specific lender terms.
What if I miss a payment?
Missing payments damages your credit score and the lender can ultimately repossess. Contact your lender immediately for forbearance options under FCA rules.
Is shorter or longer term better?
Shorter terms mean higher monthly payments but far less total interest. A £50,000 loan at 6% costs £16,600 interest over 10 years vs £46,600 over 25 years.
Official Sources & References
Data verified against official UK government sources. Last checked April 2026.