Mortgage Early Repayment Charge Calculator
Estimate an early repayment charge using your mortgage contract’s actual allowance and charge basis. Do not assume every lender allows 10% free overpayments.
Rule year: 2026/27 · GBP · Sources checked
Estimated early repayment charge under entered contract
Contractual allowance period, allowance amount, charge rate and basis already established for this specific action. No universal 10% rule, daily charge change, full-redemption waiver, other redemption fees, lender approval or interest-savings comparison. Whole-payment mode applies only once the selected allowance is exceeded.
For informational purposes only. This estimate is not financial advice, a tax return, a payroll calculation or a lender decision. See the supported circumstances and exclusions below.
How this calculator works
UK mortgage early repayment charges depend on the lender’s contract, deal period and how an overpayment allowance is measured. This calculator subtracts allowance already used, tests the proposed repayment against the remaining room and applies the entered percentage to the selected charge basis. Some terms charge only the excess; other actions can use a different or whole-payment basis. The result is valid only for the contract treatment entered. Full redemption, product transfers or changing deal dates can alter the treatment and need separate confirmation.
Formula and rules
Remaining allowance = max(0, contractual allowance − amount used). Excess = max(0, proposed payment − remaining allowance). Charge = established chargeable basis × contractual percentage / 100.
Assumptions and limitations
Contractual allowance period, allowance amount, charge rate and basis already established for this specific action. No universal 10% rule, daily charge change, full-redemption waiver, other redemption fees, lender approval or interest-savings comparison. Whole-payment mode applies only once the selected allowance is exceeded.
Worked example
A £20,000 allowance with £5,000 already used leaves £15,000 free room. An £18,000 proposed repayment exceeds it by £3,000. At a 3% excess-only charge, ERC is £90 and total cash including charge is £18,090.
- Estimated early repayment charge under entered contract
- £90.00
- Remaining entered fee-free overpayment allowance
- £15,000.00
- Amount subject to charge under chosen basis
- £3,000.00
- Total proposed payment plus estimated charge
- £18,090.00
Official sources and review
Reviewed against the sources below on 2026-10-06. Rates are held in versioned rule modules. Versioned rules, official source review and year-specific calculation tests.
- MoneyHelper: mortgage overpayments ↗
Lenders set overpayment allowances and early repayment charges. Contract terms, not a universal 10%, govern.
- MoneyHelper: Mortgage fees and costs ↗
Arrangement fees may be financed; comparing repayments alone can miss upfront costs.
Common questions
Do all mortgages allow 10% overpayments?
No. Allowance amount, balance basis and period vary by contract. Enter the terms applicable to your mortgage.
Can I use the result for full redemption?
Only if the supplied allowance and charge basis actually apply to full redemption. Lender redemption statements can include separate fees.
Does a zero charge mean an overpayment is approved?
No. It means no percentage charge under the entered assumptions. Confirm contract terms and transaction conditions with the lender.