Bridging Loan Interest Explained: Daily Accruals, Retained vs Rolled-Up vs Serviced, and What Actually Drives Total Cost in 2026

Bridging loan interest is quoted monthly — 0.75%, 0.85%, 0.95% — and most borrowers treat the headline figure as the definitive cost number. It isn't, and the habit of treating it that way is one of the more persistent problems in how bridging gets assessed. The real cost of a bridging loan is determined by how interest accrues daily, which repayment structure you choose, and whether retained interest is calculated on the gross loan or the net loan. Any one of those details can shift the total cost on a £500,000 deal by several thousand pounds compared to what the rate comparison implied.

The good news, if you're structuring a deal right now, is that H2 2026 looks like a genuine borrower's market. Lender competition is elevated. There are over 50 active UK bridging lenders chasing a finite pool of quality transactions. That creates room to negotiate on the things that actually drive total cost — not just the rate.

How bridging interest actually accrues: the daily rate calculation

Bridging loans accrue interest daily, not monthly. A quoted monthly rate of 0.85% converts to a daily rate of approximately 0.0279% (0.85% ÷ 30.4167, using a 365-day year). On a £500,000 loan, that's roughly £139.58 in daily interest. If your exit takes two weeks longer than planned — not unusual given conveyancing timelines — that's nearly £2,000 in additional interest you hadn't modelled.

The daily accrual mechanic also means early repayment genuinely saves money. If a lender quotes a six-month term but you exit at four months and 12 days, you pay interest for exactly 132 days, not five months. Most bridging lenders charge to the day, which is one of the structural features that makes bridging more rational than its reputation suggests — provided you model exit timing conservatively.

Some lenders apply minimum interest periods — typically one, two, or three months — which sets a floor on your cost regardless of how fast you exit. A lender with a three-month minimum on a deal you're confident will complete in seven weeks is more expensive than one charging 0.05% more per month without that floor. Always check this before you get anywhere near heads of terms. It's the kind of thing that's buried in the small print and then causes genuine surprise at redemption.

The three interest structures: what each one actually costs you

Retained interest

Retained interest means the lender deducts the total projected interest upfront from the loan proceeds. If you borrow £500,000 at 0.85% per month for a six-month term, total interest is approximately £25,500. The lender retains that from the advance, so your net day-one proceeds are £474,500 — not £500,000.

That's where lenders quietly diverge on calculation basis, and it's the detail that catches borrowers out more than almost anything else in bridging. Some lenders calculate retained interest on the gross loan — meaning they charge interest on the full £500,000 including the portion they've retained and that you never actually had access to. Others calculate on the net loan — the £474,500 you actually receive. The difference on a £500,000 loan retained for six months at 0.85% monthly is approximately £1,300. That widens on larger loans and longer terms, and it's rarely the first thing in the product summary. When you're comparing retained interest products across lenders at the same monthly rate, the gross vs net calculation basis is the hidden variable. I've seen experienced investors compare two seemingly identical products and pick the more expensive one because nobody asked the right question.

Retained interest suits borrowers who want certainty and don't have the cash flow to service monthly payments — the total cost is locked at the start, which at least makes budgeting straightforward. The trade-off is that your net advance is lower, which can create an LTV problem if you're working close to the lender's maximum.

Serviced (monthly) interest

You pay the interest monthly as it accrues. Your day-one advance is the full £500,000. On the same £500,000 at 0.85%, that's £4,250 per month, and your total interest cost equals exactly what you pay — no gross/net complication, no retained deduction.

This is the structurally cheapest option when you have the cash flow to sustain it. If you exit at month four rather than month six, you pay four months' interest and nothing more. The problem is practical rather than mathematical: bridging borrowers frequently don't have liquid monthly cash flow, because their capital is deployed in the deal. A developer mid-refurbishment or an investor waiting to refinance isn't sitting on £4,250 a month in free cash. Serviced interest on paper looks cheaper but isn't actually viable without financial stress — and lenders who smell a stretched cash position will price that risk back in elsewhere, so the saving you thought you'd made tends to erode.

Rolled-up (deferred) interest

Nothing is paid during the loan term. All interest accrues and is repaid at exit alongside the principal — typically from sale proceeds or a refinance.

Two risks matter here. The first is compounding: some lenders add accrued monthly interest to the outstanding balance and then charge interest on the new total. On shorter terms the compounding effect looks modest — almost ignorable. At twelve months it isn't. The second risk is LTV at redemption: lenders will stress-test whether your exit comfortably covers the rolled-up total, which means you need healthy headroom between exit value and gross loan plus accrued interest. If you're close to a lender's LTGDV limit on a development deal, rolled-up compounding can quietly push you over it by month nine — at which point you've got a headache that didn't exist at origination. For how this interacts with staged drawdowns on development finance specifically, the guide to how bridging loans work for property development projects goes into this in more depth.

Something worth noting that doesn't fit neatly anywhere else: a number of lenders market rolled-up products as though simple accrual is standard, when their actual documentation specifies monthly compounding. It's not necessarily bad faith — sometimes it's just inconsistent sales material — but it's worth reading the facility letter, not just the term sheet, before you commit.

A worked example: same loan, three structures, three different total costs

To make this concrete — £600,000 loan, 0.85% per month, six-month term, exit at exactly six months.

Retained interest (gross basis): Total retained = £600,000 × 0.85% × 6 = £30,600. Net day-one advance = £569,400. Interest charged on the full £600,000 gross.

Retained interest (net basis): Interest calculated on net advance of £569,400 only. Total interest = approximately £29,040. Same net advance, but roughly £1,560 cheaper. Same advertised monthly rate, materially different total cost.

Serviced interest: Monthly payment = £5,100. Six months = £30,600. Day-one advance = full £600,000. Total cost matches gross retained, but you've had the full £600,000 deployed throughout — your effective return on deployed capital is better, provided your cash flow supported the monthly payments.

Rolled-up interest (simple accrual): Also £30,600, paid at exit. Day-one advance = £600,000. Total at exit = £630,600.

Rolled-up interest (monthly compounding): After six months, approximately £631,780. That extra £1,180 looks like a rounding error. Run the same loan over twelve months and the compounding gap opens considerably — something in the region of £4,000-£5,000 on this loan size — which is no longer an academic distinction.

The point of the comparison isn't that one structure always wins. It's that retained on a gross basis and rolled-up with compounding are the structures that cost more than the headline rate implies, and the information needed to identify which you're dealing with requires asking questions lenders don't always volunteer.

Why the arrangement fee matters as much as the rate

A 2% arrangement fee on a £600,000 loan is £12,000. On a three-month bridge, that fee represents an additional effective annualised cost of roughly 8%, layered on top of the monthly rate. On a six-month bridge it's roughly 4%.

A lender offering 0.80% per month with a 2% arrangement fee can be more expensive overall than one offering 0.90% per month with a 1% fee, depending on loan size and term. The only honest way to compare bridging deals is on total cost — aggregate interest plus all fees, set against the net day-one advance you actually receive. Exit fees where charged, typically 1%, need to be in the model from day one as well.

For a fuller picture of what lenders are scrutinising beyond rate when they assess deal economics, the bridging finance requirements guide for 2026 covers what documentation and structuring decisions actually move the needle.

Why H2 2026 creates room to negotiate on structure — and how to use it

The bridging.fund half-year review characterises H2 2026 explicitly as a borrower's market. Increased lender competition and more than 50 active lenders chasing quality deal flow means borrowers with clean exits and credible plans have more negotiating room than they've had in several years.

What's actually negotiable? Not always the headline rate — lenders guard their published floors — but frequently the arrangement fee, the minimum interest period, the gross vs net calculation basis on retained products, and sometimes the interest structure itself. A lender who defaults to rolled-up compounding will sometimes move to simple accrual on deals above £500,000 if asked directly. Most borrowers don't ask, and most lenders don't offer.

This leverage only works if you actually have alternative lenders in play. The mechanism is market coverage. Approaching a single lender and requesting concessions is negotiating from weakness. Approaching the market with visibility across what multiple lenders will actually do on your specific deal — at what LTV, on what terms, on which interest basis — changes the dynamic. That's not a pitch for using a broker; it's just how negotiation works. Some borrowers manage it themselves perfectly well. Though to be fair, knowing which of the 50+ active lenders will actually give ground on the gross vs net basis rather than just saying they'll consider it requires either experience or a lot of declined conversations.

The rate transparency problem in the current market is also worth factoring in here. Published rates are increasingly disconnected from what deals actually price at — the gap between a rate card and real terms on a specific deal is exactly where interest structure negotiation lives, as covered in the piece on lenders going dark on real pricing. Model your total cost, model it to the conservative end of your exit timeline, and then push on structure. The headline rate is the starting point of the conversation. See also when bridging finance timing goes wrong for what happens when the exit takes longer than planned and the total cost model wasn't stress-tested.

Frequently asked questions

What is the difference between retained and rolled-up interest on a bridging loan?

Retained interest is deducted from your advance upfront — you receive less on day one but owe nothing during the term. Rolled-up interest lets you receive the full advance and repay everything at exit. The critical variable people miss is whether rolled-up accrual is simple or compound: on a six-month deal it barely matters, but at twelve months the compounding gap on a £500,000+ loan is worth several thousand pounds. Check the facility letter, not just the term sheet.

Does it matter whether retained interest is calculated on the gross or net loan?

Yes. If a lender calculates retained interest on the gross loan — the full amount before deducting the retained portion — you're paying interest on money you never received. On smaller, shorter deals this feels like a rounding issue. On a £1m+ loan retained for nine months, it isn't. The frustrating part is that two lenders can quote the same monthly rate and the gross vs net difference makes one materially more expensive. Most product summaries don't flag which basis applies.

Can I negotiate the interest structure with a bridging lender in 2026?

Often yes, though it depends heavily on deal size and how many alternatives you have in play. The current market is competitive enough that arrangement fees, minimum interest periods, and sometimes the calculation basis on retained products are all negotiable — particularly on deals above £500,000 with clean, evidenced exits. Whether a specific lender will actually move, versus saying they'll consider it and then not moving, is harder to know without direct experience of that lender's actual behaviour.

What happens to my bridging interest cost if my exit takes longer than expected?

You pay more. Daily accrual means every extra week costs real money — roughly £980 per week on a £500,000 loan at 0.85% monthly. The bigger problem is if you've modelled a tight exit and the deal doesn't cooperate: rolled-up interest keeps compounding, and if your exit is a refinance, a lender's valuation three months late can sometimes change the refinance terms you'd assumed. Build in buffer. The stress-testing matters more than the optimistic scenario.