Buy-to-let remortgage calculator
What would a remortgage look like? Enter today's position, then try a new loan size and rate — the calculator shows the interest-only monthly payment, how it compares with what you pay now, the monthly rent after the mortgage payment, and whether the new loan releases cash or needs capital put in.
Your position today
Pre-filled with a worked example — type over it with your own figures. Nothing you enter leaves your browser: no account, nothing saved.
Remortgage scenario
Try a rate and loan size against today's position — interest-only estimate, not advice.
- New payment / month
- —
- vs today
- —
- New rent after mortgage / month
- —
- Cash released
- £0
How it works
The maths is deliberately simple and fully visible. The new monthly payment is the interest-only cost of the loan you try: loan × rate ÷ 12. Rent after the mortgage payment is your rent minus that payment, before any other cost. Cash released is the new loan minus your current balance — positive means the remortgage would hand you the difference (before any fees), negative means you'd need to put capital in to land at that loan size. This is the same scenario card Primehold runs against every property inside the app, using each property's live ledger figures instead of typed ones.
What it doesn't do
- It assumes interest-only — the norm for buy-to-let, and the conservative choice. A repayment mortgage costs more per month than the figure shown.
- It ignores fees: arrangement, valuation, legal and any early repayment charge on your current deal all reduce what a remortgage actually releases.
- It doesn't test whether a lender would grant the loan. Lenders stress-test the rent against a higher notional rate and apply their own loan-to-value limits, so the loan you try here may not be available — the buy-to-let mortgage calculator runs that stress test across the standard rule-sets.
- It is arithmetic, not advice. If a scenario here looks interesting, that's the point at which to speak to a mortgage broker — not to act.
Wondering how much equity a remortgage could reach in the first place? The buy-to-let equity release calculator works out what 75% loan-to-value leaves on the table — or read how a BTL remortgage actually works.
Common questions
Can I remortgage a buy-to-let to release equity?
Yes — remortgaging to a loan larger than your current balance releases the difference as cash. The arithmetic is simply the new loan minus what you owe: a £150,000 balance remortgaged to £180,000 releases £30,000, before arrangement, valuation and legal fees and any early repayment charge on the deal you are leaving. Whether a lender will advance that loan is a separate question, decided by the property's value and by whether the rent covers the interest at the lender's stressed rate.
How much can I borrow on a buy-to-let remortgage?
Two limits apply and the lower one binds. The first is the lender's loan-to-value ceiling — 75% is a common one in buy-to-let, though plenty of loans complete below it and it is never a promise. The second is the rent test: annual rent divided by the interest coverage ratio multiplied by a stressed rate. This calculator prices a loan size you choose; the buy-to-let mortgage calculator runs the stress test that decides whether that loan is available at all.
How is a buy-to-let remortgage payment calculated?
On an interest-only mortgage — the norm in buy-to-let — the monthly payment is the loan multiplied by the rate and divided by twelve. A £180,000 loan at 5.5% is £825 a month. A repayment mortgage costs more than that, because part of the balance is repaid alongside the interest each month, so treat the interest-only figure as the floor rather than the answer.
When can I remortgage a buy-to-let?
At any point, but leaving your current deal early usually triggers an early repayment charge, which comes straight out of whatever the remortgage releases. Most landlords time it to the end of the current fixed or tracker product, and brokers typically start reviewing options in the six months before that date — after the product ends, the loan normally reverts to the lender's standard variable rate, which is usually higher.
Is remortgaging a buy-to-let worth it?
That is an arithmetic question, not a general one. Compare the new interest-only payment with what you pay now, take the rent after the mortgage payment, then set the fees and any early repayment charge against the cash released or the payment saved. If the numbers only work before costs, they do not work. This calculator shows the payment, the change versus today and the cash released; the fees have to come from your own quotes.
Run this against your whole portfolio
Inside Primehold this scenario card sits on every property, pre-filled from its live ledger — balance, rate, payment, rent — with the full dated history behind each figure and a lender-ready export one click away. Built by Scott West, a practising specialist mortgage broker.