UK Mortgage Calculator
Calculate a repayment mortgage with an initial-rate period, an entered follow-on rate and a choice of financing or paying the arrangement fee.
Rule year: 2026/27 · GBP · Sources checked
Initial monthly repayment
Capital-and-interest mortgage with equal monthly periods, no lender rounding, product transfer, remortgage fee, early-repayment charge or interest-only segment. The follow-on rate is your hypothetical input, not a forecast of the lender’s standard variable rate. LTV calculation excludes the arrangement fee.
Initial and follow-on mortgage periods
Your follow-on rate is a scenario, not a predicted lender rate. Interest is monthly, fees use your chosen treatment, and no early-repayment charge or remortgage cost is assumed.
| Period | Monthly repayment | Months |
|---|---|---|
| Initial rate | £1,334.00 | 24 |
| Entered follow-on rate | £1,398.58 | 276 |
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 offers often have an initial deal period followed by another rate, so a single-rate payment can miss a material scenario change. This model amortises the initial period, calculates the remaining balance and recalculates payment over the remaining term at your entered follow-on rate. Financing an arrangement fee increases the starting loan; paying it upfront keeps it outside that balance. LTV is shown excluding the arrangement fee, and lender treatment can differ.
Formula and rules
Starting loan = property price − deposit + financed fee. Use monthly amortisation during the initial-rate period; recalculate payment on the remaining balance and term at the entered follow-on rate. LTV excluding fee = (price − deposit) / price × 100.
Assumptions and limitations
Capital-and-interest mortgage with equal monthly periods, no lender rounding, product transfer, remortgage fee, early-repayment charge or interest-only segment. The follow-on rate is your hypothetical input, not a forecast of the lender’s standard variable rate. LTV calculation excludes the arrangement fee.
Worked example
A £300,000 property with £60,000 deposit and a £1,000 financed fee starts with £241,000 loan balance. At 0% for both entered periods over 20 years, monthly repayment is £1,004.1667 before display rounding. Fee-excluding LTV is 80%.
- Initial monthly repayment
- £1,004.17
- Payment after initial-rate period
- £1,004.17
- Mortgage balance including financed fee
- £241,000.00
- LTV excluding arrangement fee
- 80%
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 fees and costs ↗
Arrangement fees may be financed; comparing repayments alone can miss upfront costs.
- MoneyHelper: How much can you borrow? ↗
Income multiples are illustrative; lenders also assess spending, credit history and affordability.
Common questions
Is the follow-on payment a predicted lender offer?
No. It uses the rate you enter as a scenario. The actual follow-on rate and available replacement offers must be checked separately.
What changes when I finance the fee?
The loan starts higher and that fee can accrue interest. Upfront treatment instead reports the fee as cash paid outside the mortgage balance.
Does this include Stamp Duty and Council Tax?
No. Use the linked property tools for those costs. A repayment illustration is not a complete home-ownership budget.