How Bridging Loan Interest Actually Works

Bridging loan interest is the part of bridging finance people think they understand and usually do not. The monthly rate looks simple. The cost is not, because bridging loans charge interest in three quite different ways, on a balance that may be growing, over a term that rarely ends exactly when you planned.

Get those three variables right and you can compare bridging loans properly. Get them wrong and a loan that looked cheap costs more than one that looked dear.

What is the typical interest on a bridging loan?

Bridging loan interest is quoted per month, not per year, and that convention alone causes more confusion than anything else in bridging finance. Across our lender panel, bridging loan interest rates run from 0.55 percent to 1.0 percent a month.

Annualised, 0.55 percent a month is roughly 6.6 percent a year simple, and 1.0 percent a month is roughly 12 percent. Those annual figures are useful for comparison with a mortgage and misleading as a description of what you pay, because you are not holding the loan for a year in most cases. A bridging loan held for 4 months at 0.75 percent costs 3 percent of the balance in interest, whatever the annualised figure implies.

Where a bridging loan sits in that range is mostly structural. Loan to value, charge position, property type, exit strength and borrower credit all move it. Bridging loans secured at 50 percent loan to value on clean residential security price near the bottom. Bridging loans at 75 percent on unusual security with an open exit price near the top.

The Bank of England base rate of 3.75 percent, held since December 2025, sits behind all of it. Bridging loan interest rates do not track base rate directly, because bridging lenders fund from credit lines and balance sheets rather than from the base rate, but the cost of money feeds through eventually.

Do you have to pay interest on a bridging loan every month?

Usually not, and this is the single most useful thing to understand about bridging loan interest.

There are three ways interest is charged, and the choice changes what leaves your bank account and what you owe at the end.

Retained interest. The lender calculates the interest for the whole term at the outset and holds it back from the advance. You pay nothing monthly. You also receive less cash than the loan amount says. On a £300,000 bridging loan over 12 months at 0.75 percent, the interest is £27,000, so you draw around £273,000 and repay £300,000. If you redeem early, unused retained interest is normally refunded, and you should confirm that before you sign.

Rolled up interest. Nothing is deducted up front and nothing is paid monthly. The interest accrues and is added to the balance, so what you owe grows each month and everything is settled at redemption. The bridging loan cost is the same arithmetic, but the balance you owe rises over the term rather than the advance being cut at the start.

Serviced interest. You pay the interest monthly, as you would on any other loan. The balance stays flat, you draw the full amount, and you need income from day one to cover it. This suits a borrower with rental income or trading cash flow, and it is the cheapest of the three in total terms because nothing compounds.

Part serviced. A hybrid. You service some of the interest and roll the rest.

Most development and investment bridging loans are retained or rolled up, because the borrower does not yet have income from the asset. That is precisely why bridging finance exists.

How is bridging loan interest calculated?

Interest on bridging loans is normally calculated monthly on the outstanding balance, and whether it compounds depends on the method.

On serviced interest there is no compounding. You pay the month’s interest, the balance is unchanged, and next month’s interest is the same figure.

On rolled up interest it compounds. Month one’s interest is added to the balance, so month two’s interest is calculated on a slightly larger balance, and so on. Over a short term the effect is modest. Over 18 months at 1.0 percent a month it is not: £100,000 rolled up for 18 months at 1.0 percent compounding reaches roughly £119,600, against £118,000 if it were simple.

On retained interest the calculation happens once, at the start, for the full term. That makes the arithmetic simple and it means you are paying for the whole term whether you use it or not, subject to the rebate on early redemption.

Two more things affect the calculated figure. Some lenders charge interest on the gross loan including retained interest and fees, which is more expensive than charging on the net advance. And most lenders charge a minimum term, commonly 1 to 3 months, so redeeming a bridging loan in week 3 does not mean paying 3 weeks of interest.

When you receive a bridging loan quote, the two questions that matter are: is interest charged on the gross or the net, and what is the minimum term.

How much does a bridging loan cost in total?

Interest is the largest component of bridging loan cost but never the whole of it. A realistic total needs the fees as well.

Take a £250,000 bridging loan over 9 months at 0.75 percent a month, rolled up.

Interest: roughly £17,400 once compounding is included. Arrangement fee at 1.5 percent across our lender panel: £3,750. Valuation: property dependent, often £500 to £1,500 on a straightforward residential asset. Legal costs, both sides: commonly £1,500 to £3,000. Exit fee, where the lender charges one: often 1 percent, so £2,500.

Total bridging loan cost lands somewhere around £25,000 to £28,000 on a £250,000 facility held 9 months. That is roughly 10 to 11 percent of the loan, for 9 months of money.

Whether that is expensive depends entirely on what it bought. If it bought a site that would otherwise have been lost, or 9 months of sales at proper prices instead of a forced discount, it is cheap. If it bought time you did not need, it is not.

The lever that matters most is the term. Interest is charged by the month, so every month you shorten the loan is money saved, and every month you overrun costs. Borrowers consistently underestimate how long works and sales take, and a bridging loan that runs 3 months longer than planned is 3 more months of interest at a monthly rate.

Every figure here is indicative and none of it is an offer of finance. Bridging loan interest rates and fees vary by lender, security and borrower.

How much can I borrow, and what does that do to the rate?

How much you can borrow on a bridging loan is set by loan to value against the security. We arrange bridging loans up to 75 percent loan to value on residential security and 65 to 70 percent on commercial.

Leverage and bridging loan interest move together. A lender pricing a bridging loan at 50 percent loan to value has half the property’s value as protection and prices accordingly. The same lender at 75 percent has far less room if the exit slips and the asset has to be sold quickly, and the rate reflects that.

So if a quote comes back dearer than you expected, reducing the amount you borrow is often the most effective response. Dropping from 75 percent to 65 percent loan to value can move the rate more than any amount of negotiation.

Worked comparison: the same bridging loan, three interest methods

Numbers make this concrete. Take a £400,000 bridging loan for 12 months at 0.75 percent a month, across our lender panel, and run it three ways.

Retained. Interest for 12 months is £36,000. The lender retains it, so you draw £364,000 in cash and repay £400,000. Your costs are known from day one and nothing is payable monthly. If you redeem the bridging loan at month 8, you should receive a rebate of roughly £12,000 of unused interest, which is why the rebate policy is worth asking about before you sign.

Rolled up. Nothing is retained. You draw the full £400,000 and the interest compounds onto the balance. By month 12 you owe roughly £437,600. Your bridging loan cost is around £1,600 higher than the retained route because the interest is calculated on a rising balance, but you had the full £400,000 working for you throughout, which on a development or refurbishment deal is often worth more than the extra cost.

Serviced. You draw £400,000, pay £3,000 a month, and repay £400,000 at the end. Total interest is £36,000 with no compounding, so this is the cheapest of the three in pure cost terms. It only works if you have income to service it. Most bridging loans do not, because the asset is not producing yet.

The pattern holds generally: serviced is cheapest and hardest to qualify for, retained is simplest, rolled up costs slightly more and preserves the most cash. Which suits you is a cash flow question rather than a rate question.

What happens to bridging loan interest if you overrun?

This is where bridging loans get genuinely expensive, and it is the part borrowers plan for least.

A bridging loan has a term. Run past it without an agreed extension and the loan is in default, and default interest rates on bridging loans are typically several times the headline rate. A loan at 0.75 percent a month can step to 2 or 3 percent a month on default. On a £400,000 balance that is the difference between £3,000 and £12,000 a month.

Lenders vary enormously in how they handle an overrun. Some will agree an extension at the same rate if the exit is close and evidenced. Some will extend at a higher rate. Some go straight to default pricing. This is a question to ask before you borrow, not when you are already late.

The practical defence is to take a longer term than you think you need. The interest on a bridging loan is charged monthly, so a 12 month facility redeemed at month 8 costs 8 months of interest if it is rolled up or serviced, and a rebate applies if it is retained. There is rarely a penalty for being early. There is always a penalty for being late.

Borrowers routinely underestimate how long works and sales take. Build 3 months of slack into the term and the cost of that slack is nil if you do not use it.

How does bridging loan interest compare with other property finance?

Context helps, because a monthly rate looks alarming next to an annual one.

A commercial mortgage from our lender panel starts around 5.5 percent a year, and the loan runs 3 to 25 years. That is the cheapest money in property, and it is available only once the asset is finished, let or trading.

Development finance starts from 6.5 percent a year, drawn in stages against certified progress, and it funds the build itself.

Bridging loans sit above both, from 0.55 percent to 1.0 percent a month, because they are short, flexible and secured on assets that are often mid-transition. You are paying for speed and for a lender’s willingness to look at something a term lender will not.

The right comparison is therefore never bridging loan interest against mortgage interest in the abstract. It is the total cost of the bridging finance over the months you actually need it, against what the alternative route would cost including the delay, or against what happens if the deal does not happen at all.

How much can you borrow, and how does that change the interest?

How much you can borrow on bridging loans is a function of the security’s value and the charge position. We arrange bridging loans up to 75 percent loan to value on residential security and 65 to 70 percent on commercial.

Leverage and bridging loan interest rates move together, and the relationship is steeper than most borrowers expect. A bridging loan at 50 percent loan to value has half the asset’s value protecting the lender, so it prices near the bottom of the range. The same loan at 75 percent leaves far less room if the exit slips and the property has to be sold quickly, so it prices near the top.

If a bridging loan quote comes back dearer than expected, the most effective lever is usually to borrow less rather than to negotiate. Moving from 75 percent to 65 percent loan to value can shift the rate more than any conversation about pricing will.

Charge position works the same way. First charge bridging loans price below second charge every time, because a second charge lender is behind someone else in the queue and needs the first lender’s consent to be there at all.

What does bridging loan interest actually pay for?

It is worth being clear about what the cost buys, because bridging finance is often described as expensive without saying expensive relative to what.

It pays for speed. A bridging loan can complete in weeks where a term lender takes months, and on an auction purchase with a 28 day completion that difference is the whole deal.

It pays for flexibility on security. Bridging lenders will lend against property that is unmortgageable: no kitchen, no bathroom, part-built, between tenants, planning granted but nothing constructed. Mainstream lenders will not.

It pays for certainty. A principal lender making its own credit decisions can commit quickly and hold to it, and on a deal with a deadline that certainty has real value.

And it pays for the lender’s risk. Short-dated secured lending against transitional assets, repaid from a single event, is a genuinely riskier business than 25 year amortising debt against a let building. The interest reflects that.

Is a bridging loan a good idea given the interest?

It depends on the alternative, which is the honest answer to every question about bridging finance cost.

Measured against a mortgage, bridging loan interest is high and nobody should pretend otherwise. If a term lender will fund the deal on your timetable, use the term lender.

Measured against losing the deal, bridging is usually cheap. An auction lot with a 28 day completion, a property no mortgage lender will touch until the works are done, a development facility maturing with 3 units unsold: in those cases the comparison is not bridging loan interest against mortgage interest. It is the bridging loan cost against the cost of the thing not happening.

Bridging loans are a bad idea when the interest is being used to buy time for a problem that time will not solve. If the exit is a hope, the interest is just accumulating against an outcome that may not arrive.

What consumer commentators get right about bridging loan interest

Consumer money advice treats bridging loans cautiously, and for homeowners that caution is sound. Short-term secured borrowing at monthly interest, with fees, against a home, is genuinely risky for someone bridging a personal cash gap. If that is your situation, take regulated advice.

Development and investment bridging is a different activity. It is a working tool with a modelled exit, used deliberately for a defined period as part of a business. The interest is a cost of doing the deal rather than a cost of being stuck.

Both are true at once, and which applies depends on who is borrowing and why.

What to ask before you accept a bridging loan quote

Ask how the interest is charged: retained, rolled up or serviced. Ask whether it is calculated on the gross loan or the net advance. Ask what the minimum term is. Ask whether unused retained interest is refunded on early redemption. Ask whether there is an exit fee and what triggers it. Ask what the default rate is if the loan runs past term, because that number is often several times the headline rate and it is the one that hurts.

Then compare bridging loans on total cost to your realistic redemption date rather than on the monthly rate, and add a couple of months to your own timetable before you do.

If you want that arithmetic run against a live deal, we arrange a bridging loan across a panel of over 100 lenders and will quote total cost rather than a headline rate. Where the scheme is ground-up, that is development finance. Where a development loan is maturing with stock still to sell, that is development exit finance.

Construction Capital is a trading name of Lenzie Consulting Ltd, registered in England and Wales, company number 08174104. We are a commercial finance broker and introducer, not a lender, and we are not authorised by the FCA. Where a case is a regulated activity we arrange it through lenders who hold the relevant FCA permissions. Written by Matt Lenzie.