How do I use a bridging loan calculator?

What You Need Before You Start

To get a useful result from a bridging loan calculator, have these figures ready:

• Property value — the current open market value of the security property (not the purchase price, unless they’re the same)
• Loan amount — what you want to borrow
• Loan term — how many months you expect to need the facility (be honest; most problems arise from underestimating)
• Monthly interest rate — typically 0.45% to 1.2% depending on your LTV and profile
• Arrangement fee — usually 1–2% of the gross loan

Understanding the Key Inputs

Loan-to-Value (LTV)

LTV is the loan amount expressed as a percentage of the property value. Most UK bridging lenders cap at 70–75% on standard residential security, though some specialist lenders reach 80% for strong borrowers.

Example: A £400,000 property with a £280,000 loan = 70% LTV.

LTV is the single biggest factor in the rate you’re offered. Drop from 75% to 65% LTV and you might save 0.15–0.2% per month — on a £500,000 loan over 9 months, that’s roughly £6,750–£9,000 in interest saved.

Monthly Rate vs APR

Bridging loans quote interest monthly. When lenders advertise an APR, they’re annualising that monthly rate. A 0.75% monthly rate equates to approximately 9.4% per annum (compounding). Don’t compare a bridging rate directly to a mortgage rate without adjusting for the compounding effect.

Rolled-Up vs Serviced Interest

Most bridging loans are rolled-up — interest accrues each month and is repaid as a lump sum when the loan is redeemed. Some lenders offer serviced (monthly-paid) interest, which keeps the outstanding balance flat but requires monthly cash payments. A calculator should allow you to choose between these two modes.

Worked Example — Auction Purchase

Scenario: You’re buying a residential property at auction for £350,000. You expect to refinance to a buy-to-let mortgage in 6 months after a light refurbishment.

Calculation:

• Month 1 balance: £262,500 × 1.0065 = £264,206
• Month 6 balance (compound): £262,500 × (1.0065)^6 = £272,901
• Total interest: £272,901 − £262,500 = £10,401
• Arrangement fee: £3,938
• Estimated legal + valuation: £3,000
• Total cost of borrowing: approx. £17,339

Worked Example — Chain Break

Scenario: You need to move into a new home at £600,000 while your existing house (worth £450,000, no mortgage) is on the market. You expect to sell within 4 months.

• Total interest (rolled-up): £315,000 × [(1.0075)^4 − 1] = £9,566
• Arrangement fee: £6,300
• Estimated legal + valuation: £3,000
• Total cost: approx. £18,866

What the Output Means

A well-built bridging loan calculator will show:

• Gross loan — the total facility, including any rolled-up interest and fees deducted upfront
• Net advance — what you actually receive
• Monthly interest accrual — useful for seeing how the balance grows if you run close to the term
• Total repayable — everything you need to pay to redeem the loan
• Effective APR — the annualised cost for comparison

How to Use the Results

Use the calculator output to:

1. Stress-test your exit — if your property sale takes 3 months longer than expected, what does that add to the balance?
2. Compare lenders — a lower rate but higher arrangement fee isn’t always cheaper; the calculator makes this clear
3. Check net proceeds — make sure the net advance actually covers what you need to pay on completion day
4. Decide between rolled-up and serviced — if you have monthly cash flow, serviced interest keeps total cost lower

Tips for Getting the Best Rate

• Apply at 65% LTV or below if possible — rates improve markedly at this threshold
• Use a broker rather than going direct; whole-of-market brokers access rates not available on lender websites
• Have your exit strategy documented before you apply — lenders who understand how you’ll repay move faster and offer better terms
• Avoid extending your term; extension fees and higher rates for overshoot periods add up quickly