Complete guide
Mortgage Calculator UK: formula, worked example and interpretation
Estimate UK repayment-mortgage or interest-only monthly payments in pounds. Enter the known values and the result updates instantly with an auditable breakdown.
What the Mortgage Calculator UK answers
Estimate UK repayment-mortgage or interest-only monthly payments in pounds.
Use the breakdown to compare the result with the source values before making a decision.
Formula and variables
The calculation uses repayment=P×r/[1−(1+r)^−n]; interest-only=P×r. Every variable comes directly from a labeled field.
repayment=P×r/[1−(1+r)^−n]; interest-only=P×rWorked example
A £350,000 home with £70,000 deposit leaves a £280,000 mortgage for the selected term.
Changing any field recalculates the result immediately, so nearby scenarios can be compared without reloading the page.
How to use the result
Treat the result as a planning value and compare it with the detailed rows shown beside it.
Keep units and time periods consistent. Use the share or PDF action to preserve the exact assumptions.
Assumptions and scope
Product fees, introductory periods, affordability checks, taxes, insurance and changing rates are not included.
The calculator exposes its assumptions instead of filling missing facts with hidden estimates.
Accuracy checks
Confirm the units, dates, rates and source figures before relying on the output.
Round only the displayed answer; Calculator24 keeps full JavaScript precision for intermediate arithmetic and exported values.
Input and output checklist
| Item | What to enter or review |
|---|---|
| Inputs | Mortgage type, Property price (£), Deposit (£), Annual interest rate (%), Term (years) |
| Equation | repayment=P×r/[1−(1+r)^−n]; interest-only=P×r |
| Example | A £350,000 home with £70,000 deposit leaves a £280,000 mortgage for the selected term. |
| Limit | Product fees, introductory periods, affordability checks, taxes, insurance and changing rates are not included. |
Frequently asked questions
What does this Mortgage Calculator UK calculate?
Estimate UK repayment-mortgage or interest-only monthly payments in pounds.
Which formula does it use?
repayment=P×r/[1−(1+r)^−n]; interest-only=P×r
Does the result update while I type?
Yes. Valid changes recalculate after a short delay and the previous result is not substituted for invalid input.
Which assumptions should I check?
Check units, rates, dates and every source value shown in the form.
Is the result exact?
Product fees, introductory periods, affordability checks, taxes, insurance and changing rates are not included.
Can I save or share the calculation?
Yes. Copy, Share, WhatsApp, PDF/Print, CSV, comparison and parameterized-link actions are available.
What to keep in mind
Product fees, introductory periods, affordability checks, taxes, insurance and changing rates are not included.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.