A bridging loan calculator should do one thing well: show you the full cost of a short-term facility before you commit to it. Most do not. The gap between what a calculator tells you and what a bridging loan actually costs is where borrowers get surprised, and it gets wider the more complex the deal.
This guide explains what a bridging loan calculator needs to show, where the common tools fall short, and what to look for before relying on any figure you get from one.
FD Commercial arranges bridging loans from £250,000. No broker fee on most transactions. Our calculator is available at fdcommercial.co.uk/bridging-loan-calculator/
Key points
Most online bridging loan calculators model simple interest on a flat loan balance. They do not account for rolled-up compounding interest, arrangement fees added to the facility, gross LTV versus net LTV, or the early redemption figure at each month of the term. A calculator that misses any of these is likely to understate the cost of the loan.
Price comparison sites do not have genuine bridging calculators. Consumer information sites have basic tools. Lender calculators are built for intermediaries, not borrowers. The most complete public bridging loan calculators sit with specialist brokers, and the quality varies considerably.
What a bridging loan calculator needs to show
Before assessing any calculator, it helps to know what a thorough one actually produces. The minimum a bridging loan calculator should give you is:
Gross loan advance. The total facility including any arrangement fee added to the loan. This is the figure interest accrues on, not the net amount you receive. A calculator that uses only the net loan understates both LTV and total interest.
Live LTV. Calculated on the gross advance as a percentage of the property value. Most bridging lenders cap at 65% to 75% depending on asset type. The rate you pay is a function of LTV. A calculator with no LTV output cannot suggest a realistic rate.
Rolled-up versus serviced interest. These produce materially different costs. Rolled-up interest compounds monthly: interest accrues on interest. Serviced interest is paid monthly and the balance stays flat. The difference over a 12-month term at standard rates on a £500,000 facility is approximately £3,000 to £5,000. A calculator that only does one type is not giving you the full picture.
All fees itemised. Arrangement fee, exit fee, valuation fee, legal fees and any admin charge. Total interest and total fees are both part of the cost of borrowing. A calculator that shows only interest is incomplete.
Month-by-month balance and early redemption figure. Bridging loans are often repaid before the full term. The redemption figure at month three is significantly different from month twelve on a rolled-up facility. A calculator that only gives you the cost at full term does not help if your exit is likely to be early.
With those criteria established, here is how the main categories of online tool measure up.
Price comparison sites
Price comparison sites have a bridging loans section. What they do not have is a bridging loan calculator. The tools on these pages are standard personal loan repayment calculators: they take a loan amount, a rate and a term and produce a monthly repayment figure. That model is built for unsecured lending repaid in equal monthly instalments.
Bridging finance does not work that way. There are no monthly capital repayments. Interest is usually rolled up. The gross advance differs from the net advance. LTV governs rate. None of this is captured by a repayment calculator.
What comparison sites actually provide in their bridging sections is a panel of lenders or a referral to a single partner provider. The calculator on the page is decorative. It tells you nothing specific about what a bridge will cost.
Consumer information sites
Consumer finance information sites take bridging loans seriously as a topic. Some have calculator tools; some have only illustrative examples in the editorial. The tools that do exist tend to cover the basics: a loan amount, a rate and a term produce a total interest figure and a total repayment. Legal fees and valuation costs may be included as fixed estimates.
Where these tools fall short is precision. A fixed illustrative rate does not reflect what your LTV or asset type actually costs. There is no rolled-up versus serviced toggle. There is no gross loan calculation. The month-by-month breakdown is absent. The figures are directionally useful but not accurate enough to budget against.
Some of these calculators are also powered by a single lender or broker partner, which means the rate defaults are set by one provider's book rather than the market. That is not declared prominently.
Lender calculators
Specialist bridging lenders do offer calculator tools. The better-built ones model interest on the gross advance, show the LTV, and allow for rolled-up compounding. The limitation is access and scope. Many lender calculators sit behind an intermediary portal and are not available to borrowers directly. Those that are publicly accessible are built to illustrate the lender's own product range and rate card, not to give a market-wide picture.
A lender calculator is useful if you already know which lender you are going to. If you are at the stage of comparing options or assessing whether a bridge makes sense for your deal, a lender-specific tool gives you a narrow view.
Property platform calculators
Property investment platforms and landlord tools have increasingly added bridging loan calculators as a feature. The user experience tends to be good: clean interfaces, quick inputs, fast results. The underlying model is often less sophisticated than it appears.
The most common issue is that these calculators are lead generation tools, not neutral cost modelling tools. The goal is to capture an enquiry. The rate defaults are often optimistic. The gross loan calculation is missing or simplified. The output steers you toward the platform's own lending product or panel.
There is nothing wrong with that as a business model. But it means the calculator result reflects what the platform wants to show you, not necessarily what the deal will cost.
What FD Commercial's calculator models
We built our own bridging loan calculator because nothing freely available did what we actually needed when explaining costs to clients. The calculator is available publicly at fdcommercial.co.uk/bridging-loan-calculator/ and covers the following:
Asset type and auto-suggested rate. Select residential, mixed use, commercial or land. The calculator suggests an indicative monthly rate based on your LTV and asset type, reflecting how lenders actually price risk. You can override this manually if you have a specific rate to model.
Gross loan calculation. Enter your existing charges and the additional funds required. The calculator adds the arrangement fee to the loan if you select that option and shows the gross advance, with live LTV calculated on that gross figure.
Rolled-up or serviced toggle. Switch between interest types and the results update immediately. Rolled-up interest compounds monthly on the outstanding balance. Serviced interest keeps the balance flat with a fixed monthly payment.
Full fee itemisation. Arrangement fee percentage, exit fee percentage (on gross or net loan), valuation fee, legal fees and admin costs all input separately. The results show total interest, total other fees and a grand total cost of the facility.
Month-by-month redemption table. Every month of the term shows the interest charge, the outstanding balance and the early redemption figure. If your exit is at month four, you can read the figure directly rather than reverse-engineering it from the totals.
LTV warnings. The calculator flags when gross LTV exceeds 75% or 80%, where lender options narrow and rates rise. This is relevant context that a simple cost calculation does not surface.
We are a specialist broker, not a lender. The calculator is not designed to steer you toward a specific product. It is designed to give you an accurate cost picture before you speak to us or anyone else.
Example: what the full calculation looks like
Property value: £800,000. Existing mortgage: £200,000. Additional funds required: £200,000. Total loan: £400,000. Arrangement fee: 2% added to loan (£8,000). Gross advance: £408,000. LTV: 51%. Rate auto-suggested at 0.80% per month. Term: 9 months rolled-up. Valuation: £1,000. Legal: £1,500. Admin: £300.
Total interest: £29,866. Other fees: £11,800. Grand total cost: £41,666. Month 6 early redemption figure: £422,039.
A simple interest calculation on £400,000 at 0.80% over 9 months gives £28,800. That understates the true cost by over £12,000 once compounding, the gross advance and all fees are included.
Questions to ask of any bridging loan calculator
Before relying on a result, run through these quickly. Does the calculator use the gross loan or the net loan as the interest base? If it uses the net loan, it is understating the cost. Does it compound interest monthly or calculate simple interest? Simple interest understates the rolled-up cost significantly over terms above six months. Does it show an LTV based on the gross advance, or based on the loan amount before fees? Does it show the redemption figure at each month, or only at the end of the full term?
If a calculator cannot answer yes to all four, treat the output as directional rather than accurate.
How to use a bridging loan calculator effectively
Use it to test scenarios before you have a conversation with a broker. Run the numbers at three LTV levels: what you need, 5% below that, and 5% above. The rate and cost difference is often significant enough to change how you structure the deal: for example, whether it makes sense to put in more equity at the outset to access a lower rate tier.
Run it with rolled-up and serviced interest side by side. If you have the monthly cash flow to service the interest, the total cost saving over a 12-month term is meaningful. If cash flow is tight during the project, rolled-up is the right structure regardless of the total cost difference.
Use the month-by-month table to set a realistic exit timeline. If you are selling a property, allow for two to three months beyond your expected completion date. The calculator will show you what that extension costs on a rolled-up basis. That figure belongs in your deal appraisal.
What we find in most cases is that developers and investors who have run accurate calculator figures before speaking to a lender or broker negotiate better. They know the LTV they need to hit, the rate range that makes the deal viable, and the maximum term they can absorb. That gives the broker a much tighter brief.
Frequently asked questions
What should a bridging loan calculator include?
A useful bridging loan calculator should show the gross loan advance (loan amount plus any arrangement fee added to the facility), a live LTV figure based on property value, total rolled-up or serviced interest over the full term, arrangement fee, exit fee, valuation and legal costs, and a month-by-month balance with an early redemption figure for each month. A calculator that shows only a single interest total without a breakdown is not giving you enough information to assess the deal.
Do price comparison sites have bridging loan calculators?
Price comparison sites do not offer genuine bridging loan calculators. Their tools are built for personal loans and standard mortgages. Bridging loan sections on comparison sites typically redirect to a panel of lenders or a single partner provider rather than offering a cost modelling tool. The core problem is that bridging loan costs depend on variables that a personal loan repayment calculator cannot handle: rolled-up versus serviced interest, arrangement fee structure, exit fee basis, and asset type.
What is the difference between rolled-up and serviced interest on a bridging loan?
Rolled-up interest means monthly interest is added to the loan balance rather than paid each month. The balance compounds throughout the term and is repaid in full on redemption. Serviced interest means you pay the monthly interest charge each month, so the loan balance stays flat. Rolled-up interest is more common for short-term bridging because it requires no monthly outgoings, but it produces a higher total cost because interest accrues on interest. Your calculator should let you model both.
Why does LTV matter for a bridging loan calculator?
LTV determines both whether a lender will fund the loan and what rate applies. Most bridging lenders cap gross LTV at 75% for residential property, lower for commercial and land. The rate rises as LTV increases. A calculator that does not show live LTV, or that calculates LTV on the net loan rather than the gross advance, is not giving you an accurate picture of the deal or the rate that should apply to it.
What is the arrangement fee on a bridging loan?
The arrangement fee is a lender charge for setting up the facility, typically 1% to 2% of the gross loan. It can either be paid upfront or added to the loan, in which case it increases the gross advance and therefore the LTV and the interest base. A good calculator should let you toggle this and show the impact on LTV and total cost.
How accurate are online bridging loan calculators?
Online bridging loan calculators give indicative cost estimates, not quotes. Actual rates depend on the lender, the property, the borrower profile and the exit strategy. A calculator using an auto-suggested rate based on LTV and asset type gives a more realistic starting point than one that defaults to a single illustrative rate. Use calculator results to understand the cost structure and test scenarios, not to budget precisely before speaking to a specialist.
What is the minimum bridging loan FD Commercial arranges?
FD Commercial arranges bridging loans from £250,000 across England, Scotland and Wales. No broker fee on most bridging transactions.
Run the numbers on our calculator, then speak to us. We know which lenders match your LTV, asset type and exit strategy. We will tell you if the deal does not stack before you commit to it.
Call 03300 100315Indicative rates shown in examples are for illustrative purposes only and do not constitute an offer or quote. Actual bridging loan rates depend on lender, property type, LTV, borrower profile and exit strategy. Property may be repossessed if a loan secured against it is not repaid. Rates correct as of 2026.