Invoice factoring vs overdraft: which is better for small business cash flow?

The Direct Answer: Two Different Tools for Two Different Problems

Invoice factoring and a business overdraft both solve the same underlying symptom — a gap between money going out and money coming in — but they solve it in fundamentally different ways. An overdraft is a revolving credit facility attached to your business current account that lets you spend up to an agreed limit beyond your balance. Invoice factoring is the sale of your unpaid customer invoices to a finance provider, who advances you typically 80–90% of the invoice value immediately and pays you the remainder (minus fees) once your customer settles. One is borrowing against your balance sheet; the other is selling an asset you already own.

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The honest answer to "which is better" is that neither is universally superior. Overdrafts tend to be cheaper for short, predictable dips — a VAT quarter, a slow fortnight, a one-off equipment purchase. Factoring tends to work better when your cash flow problems are structural rather than incidental: you have strong sales but customers pay on 30, 60 or even 90-day terms, so your working capital is permanently locked up in receivables. If your problem is "customers pay slowly," factoring attacks the cause. If your problem is "this month is unusually tight," an overdraft is usually the simpler, cheaper fix.

For small and medium-sized businesses in 2026, the decision also depends on what you can actually get approved for. Bank overdrafts have become harder to secure since the withdrawal of pandemic-era support schemes such as the Coronavirus Business Interruption Loan Scheme (CBILS) and its large-business counterpart CLBILS, which ended to new applications years ago. Government-backed lending now flows mainly through the Growth Guarantee Scheme — Santander alone has committed £20 million to businesses through it, according to reporting by the Greater Birmingham Chambers of Commerce — but eligibility criteria remain stricter than many owners expect. Factoring providers, by contrast, underwrite primarily against your customers' creditworthiness rather than yours, which makes it accessible to younger businesses with thin trading histories.

How Invoice Factoring Actually Works

With factoring, you raise an invoice as normal, then assign it to the factor. The provider verifies the invoice, runs credit checks on your customer, and advances you a percentage of the face value — commonly 85%, sometimes ranging from 70% to 90% depending on the sector and debtor quality. Your customer is notified to pay the factor directly (this is "disclosed" or "notification" factoring), and once payment lands, the provider releases the remaining balance minus their charges.

Costs come in two parts. First, a discount fee or service charge, usually expressed as a percentage of turnover — often between 0.5% and 3% of invoice value per month equivalent, though effective annual costs can run higher. Second, a discount rate on the money advanced, often quoted as a margin over base rate, frequently base plus 2–4%. On a £50,000 invoice paid after 60 days at a 3% monthly-equivalent discount fee, you might give up roughly £3,000 in fees — expensive compared with a bank overdraft at, say, 8–12% APR on the same amount over the same period.

There are variations worth knowing. Confidential invoice discounting keeps the arrangement invisible to your customers — they keep paying you directly — but usually requires you to have an in-house credit control function and a minimum turnover (often £250,000+). Spot factoring lets you sell single invoices without a whole-ledger commitment, useful for occasional gaps but priced at a premium. Recourse versus non-recourse terms matter too: non-recourse means the factor absorbs bad debt if a customer defaults, at a higher fee; recourse means the risk stays with you.

How a Business Overdraft Works

An overdraft is a pre-approved negative balance allowance on your business account. You apply through your bank, they assess your accounts, trading history, credit file and sometimes security, and if approved you get a limit — anything from £1,000 for a micro-business to six figures for established firms. Interest accrues daily only on what you actually use, typically at a margin over the Bank of England base rate. Many banks also charge arrangement fees of 1–2% of the limit and monthly maintenance fees of £5–£30.

The appeal is flexibility and cost efficiency. You draw nothing until you need it, repay whenever cash allows, and redraw without reapplying. For a seasonal business — a retailer stocking up before Christmas, a landscaping firm surviving winter — an overdraft sized to the seasonal trough can be far cheaper than financing every invoice through a factor.

The drawbacks are real, however. Limits are often modest relative to receivables — a business invoicing £500,000 a year may only be offered a £10,000–£25,000 overdraft. Approval requires decent credit history and usually two to three years of accounts, locking out startups. Banks can reduce or withdraw facilities at short notice — this happened widely during 2020 when lenders reassessed exposure — leaving businesses stranded mid-dip. And personal guarantees are routinely demanded from directors of smaller companies, putting personal assets on the line in a way factoring does not.

Head-to-Head Comparison

Read the table honestly: factoring wins on accessibility, scalability and speed relative to receivables; overdrafts win on cost, discretion and simplicity. A firm turning over £300,000 with 60-day payment terms could unlock roughly £150,000 of tied-up cash through factoring — several times what a typical overdraft would offer — but will pay meaningfully more for it.

When Factoring Is the Better Choice

Factoring earns its place in specific circumstances. If your customers are large corporates or public-sector bodies paying on 45–90 day terms, your receivables book is likely your largest untapped asset. A recruitment agency placing contractors weekly, a haulage firm billing blue-chip clients, or a manufacturer supplying supermarket chains all fit the profile: high-quality debtors, slow settlement, growing order books. Because funding grows automatically with sales, factoring supports growth without repeated trips back to the bank — a genuine advantage over a fixed overdraft limit you outgrow within months.

It also suits businesses that cannot access traditional credit. A company trading for eight months with no filed accounts will struggle with most banks but can still factor if its customers pass credit checks. Outsourced credit control — included in most full-service factoring agreements — is another practical benefit for owner-managed firms without a finance team, though some owners dislike surrendering control of customer contact.

Be clear-eyed about downsides. Effective annual costs of 15–30% are not unusual once fees stack up, which is materially more than a well-priced overdraft. Customer notification can unsettle relationships if handled clumsily. Minimum contract terms of 6–12 months with exit penalties are common, so a short-term gap solved badly with a year-long factoring agreement costs more than it should. And if your margins are thin — below roughly 10–15% — factoring fees can consume a painful share of profit.

When an Overdraft Is the Better Choice

Choose the overdraft when your cash gap is temporary, predictable and modest. A quarterly VAT bill of £18,000 against a £20,000 overdraft facility is exactly what the product was designed for: borrow for three weeks, repay, pay interest on perhaps £9,000 of average usage for a month — a few hundred pounds total. Financing those same invoices through a factor would cost more and commit you to a longer relationship.

Overdrafts also suit businesses whose customers pay reasonably promptly but whose outgoings are lumpy — professional services firms with irregular project milestones, retailers managing stock cycles, trades businesses buying materials upfront. If your average debtor days sit below 30 and your issue is timing rather than structure, cheaper revolving credit beats selling receivables.

The critical caveat is availability and stability. Since CBILS and CLBILS closed, standard commercial lending criteria apply again, and approval rates for unsecured SME facilities have tightened. If your bank offers a sensible limit at a fair price, take it and treat it as a buffer — but do not build a growth plan on a facility the bank can withdraw with 30 days' notice. Diversifying across at least one alternative funding line is prudent risk management, not pessimism.

Practical Steps Before Deciding Either Way

Start by quantifying the problem properly. Calculate your average debtor days (receivables divided by daily sales). If it exceeds 45 days and is trending upward, factoring deserves serious consideration. If it sits around 30 and the gap is seasonal, price overdrafts first. Model the true cost of each option over twelve months using your actual expected volumes — not headline rates. A factoring quote of 2% per month sounds manageable until applied to your full ledger for a year.

Then check your own eligibility reality. Pull your business credit file, prepare 12–24 months of management accounts, and ask your existing bank first — incumbents often price loyalty competitively, and switching banks purely for an overdraft is disruptive. In parallel, obtain quotes from at least three factoring providers; pricing varies widely, and brokers can surface deals not advertised publicly. Ask specifically about total cost of a typical invoice cycle, notice periods, minimum term commitments, and whether the facility is recourse or non-recourse.

Finally, consider whether either product is even the right frame. Asset-based lending bundles factoring with equipment finance. Revenue-based finance repays as a percentage of card takings for consumer-facing firms. The Growth Guarantee Scheme remains the main government-backed route for term loans where security is lacking, with lenders like Santander actively deploying capital through it. An AI-driven cashflow coach — the category Glassjar operates in — adds value here by forecasting your actual cash position weeks ahead, so you arrange the right facility before the gap hits rather than reacting under pressure. Forecasting accuracy, not product selection, is where most cash crises are actually won or lost.

Common Mistakes Businesses Make

The most frequent error is choosing on headline rate alone. A cheap-looking overdraft with a low limit that runs dry every month forces emergency borrowing elsewhere — often at punitive rates — making the "expensive" factoring deal the cheaper outcome in practice. Conversely, signing a 12-month factoring contract to cover a one-off £15,000 dip is a classic misfit; spot factoring or a short-term loan would have been appropriate.

Second, owners underestimate the operational change factoring brings. Once customers are notified to pay a third party, some will query invoices more aggressively or delay further. Reputable factors handle collections professionally, but read reviews and ask how disputes are managed before signing. Third, businesses ignore concentration risk: if one customer represents 40% of your ledger, factors will cap exposure to them, and losing that customer guts your facility overnight. Fourth, directors sign personal guarantees on overdrafts without understanding that these survive insolvency and are rarely released voluntarily — negotiate caps or time-limited guarantees where possible.

Fifth, and most damaging: treating any credit facility as a substitute for fixing payment terms. If your contracts allow 60-day payment, negotiate deposits, milestone billing or early-payment discounts instead. Finance should bridge deliberate strategy, not subsidise avoidable slowness.

Timing: When to Act

Arrange finance before you need it. Applications made from a position of strength — healthy accounts, no missed payments — attract better pricing and higher limits. Realistically, allow four to eight weeks end to end: two to three weeks for factoring onboarding including debtor verification, and anywhere from two to six weeks for an overdraft depending on whether security is involved. If your busy season starts in September, begin conversations in July.

Watch leading indicators rather than waiting for crisis: debtor days creeping past 40, a pipeline that will strain your current limit, or a bank letter reviewing your facility. Any of these means start the process now. And review whichever facility you choose annually — overdraft limits that fitted a £200,000 turnover business are inadequate at £400,000, and factoring rates should be re-tendered every couple of years because the market is competitive and loyal customers routinely overpay.

Bottom Line

Invoice factoring converts slow-paying invoices into immediate cash and scales with your sales, at a cost of roughly 0.5–3% per month plus margin — ideal for growing B2B firms with creditworthy customers on long payment terms. An overdraft is cheaper, discreet and flexible for short predictable gaps, but harder to obtain, limited in size, and revocable. Most well-run SMEs eventually hold both: an overdraft as a low-cost buffer, and invoice finance as the growth engine when receivables balloon. Whichever you pick, model the full-year cost against your real numbers, read the exit clauses twice, and invest in forecasting so you never need emergency funding at all.