Free calculator
See the debt cost before the rest of the deal starts looking easier than it is.
Check monthly repayment or interest-only drag, LTV, and stressed debt changes so the finance layer stays visible from the start.
A planning tool for investors, not a lender quote. Use it to understand the debt drag inside the deal before you move deeper.
Repayment or interest-only
LTV visible
Stress-rate check
Best for
Understanding the real monthly burden before you trust a headline rent or yield.
Comparing repayment against interest-only in the same quick read.
Seeing how a modest rate move changes the shape of the deal.
What disciplined readers do next
Feed the debt drag into ROI and stress testing, not into a separate mental silo.
Compare the stressed monthly payment against realistic rent support, not best-case letting.
Watch the LTV because it changes both risk posture and lender flexibility.
Inputs
Load the finance layer first
Most deals feel different once the actual debt drag is in view. This page is there to make that obvious quickly.
Outputs
Keep the debt burden visible before you trust the rest
This is where repayment and interest-only should stop being abstract. The monthly drag affects everything else downstream.
Loan amount
£135,000
The mortgage balance based on property price less deposit.
Loan-to-value
75.0%
A quick risk and lender-flexibility signal.
Selected monthly payment
£870
This is the monthly drag for the repayment type you selected.
Interest-only reference
£675
Useful even when you are underwriting a repayment route, because it shows the pure interest burden.
Stressed monthly payment
£1,042
The payment after the stress-rate shift is added to the current rate.
Total interest
£125,942
For long-hold thinking, this shows how expensive the debt becomes over the term.
How to read this cleanly
If the stressed payment starts to crowd out the monthly margin, the deal is thinner than it first appears.
If the LTV is already high, you have less room for weak rent or weak valuation.
If the repayment route only works on optimistic rent, the discipline should stay soft.
Best next step
Use the payment view to sharpen the full underwrite.
This page is not the whole answer. It just stops the debt burden from being an afterthought when the rest of the deal starts to look attractive.
Quick truth: many weak deals look better in conversation than they do once the finance drag is stated clearly.