What is the cash conversion cycle?

The cash conversion cycle measures how many days pass between paying cash out for inputs and receiving cash in from customers. It's calculated as days inventory outstanding plus days sales outstanding, minus days payable outstanding. A shorter cycle means cash returns to the business faster; a longer or negative cycle ties up more working capital."

Can a profitable business really run out of cash?

Yes — this is one of the most counterintuitive and important lessons in financial modelling. Profit is an accounting measure of revenue minus costs; cash is a timing measure of when money actually moves. A business can record a profit in a period while its bank balance falls, if customers pay slowly and suppliers must be paid quickly."

Why does growth make working capital problems worse, not better?

Each new pound of revenue typically requires working capital to be committed before the cash comes back — inventory bought, work delivered before invoicing, staff paid before the client settles. The faster a business grows, the more of this unpaid working capital it needs simultaneously, which is why rapid growth is a common trigger for cash crises even in profitable businesses."

What's the difference between days sales outstanding and days payable outstanding?

Days sales outstanding measures the average time it takes to collect cash from customers after a sale. Days payable outstanding measures the average time a business takes to pay its own suppliers. A business that collects quickly and pays slowly has more working capital available; one that collects slowly and pays quickly needs more capital tied up to bridge the gap."

Should a visa business plan include a working capital calculation?

It doesn't need to be a standalone formal schedule for every applicant, but any plan involving inventory, B2B invoicing with payment terms, or a service delivered before payment should show that the founder has thought about the cash-timing gap, since it directly affects the runway and break-even numbers assessors are reading closely."

Working capital: modeling growth without running out of cash

A business can be profitable on paper and still run out of cash. This isn't a contradiction — it's one of the most important, and most commonly overlooked, distinctions in financial modelling. Profit measures revenue minus costs over a period. Cash measures when money actually moves. A business that sells on 60-day payment terms but pays its own suppliers in 14 days can show a healthy profit while its bank balance quietly falls, and the faster that business grows, the faster the gap widens.

Key rules

Profit and cash answer different questions. The cash conversion cycle is the tool that tells you whether growth will fund itself or starve your bank account.

"Growing broke" is real. A profitable, growing business can run out of cash purely because of payment-timing mismatches — nothing to do with the underlying unit economics being wrong.
The cash conversion cycle has three components. Days inventory outstanding, plus days sales outstanding, minus days payable outstanding.
Growth increases working capital need, not just revenue. Each new pound of sales typically requires cash to be committed before it comes back.
This connects directly to your runway. A working capital gap you haven't modelled shows up as a runway shortfall you didn't see coming.
B2B and inventory-based businesses are most exposed. Simple, prepaid, low-inventory models carry far less of this risk.

The core distinction: profit versus cash

The cash flow statement explained covers the mechanics of why profit and cash diverge. The short version relevant here: revenue is recognised when a sale happens, not when the customer actually pays; costs are recognised when incurred, not necessarily when cash leaves the bank. Working capital is the gap that sits between those two timings, and it has to be funded from somewhere — usually your 24-month runway — while you wait for it to close.

The businesses that get caught out by working capital aren't the unprofitable ones. They're the profitable ones growing fast enough that the cash-timing gap outruns the runway built to cover it.

— Duke Harewood, Founder, TorlyAI

The cash conversion cycle, explained

The cash conversion cycle (CCC) measures how many days pass between cash going out for inputs and cash coming back in from customers. It has three components:

Days Inventory Outstanding (DIO) — how long, on average, stock sits before being sold. Only relevant to businesses holding physical inventory; zero for most pure-service or SaaS businesses.

Days Sales Outstanding (DSO) — how long, on average, it takes to collect cash after a sale is invoiced. A business on 30-day payment terms with prompt-paying customers might see a DSO close to 30-35 days; one with slow-paying enterprise clients might see 60-90 days in practice.

Days Payable Outstanding (DPO) — how long, on average, the business takes to pay its own suppliers.

Cash Conversion Cycle = DIO + DSO − DPO

A worked example

A business selling B2B software with 45-day average customer payment terms, no physical inventory, and 30-day supplier payment terms:

CCC = 0 (no inventory) + 45 (DSO) − 30 (DPO) = 15 days

For every pound of monthly revenue, roughly 15 days' worth of cash is tied up between paying costs and collecting from customers. At £50,000 monthly revenue, that's roughly £25,000 of working capital permanently committed to bridging the gap — capital that has to come from somewhere and doesn't show up as "cost" on the P&L at all.

Contrast with a business selling on annual upfront payment terms: DSO effectively becomes negative relative to delivery, meaning cash arrives before the cost of delivering the service is fully incurred. This is why prepaid or subscription-upfront business models are structurally easier to fund — they generate working capital rather than consuming it.

Why growth makes this worse

The intuitive assumption is that growth solves cash problems — more revenue should mean more cash. Working capital dynamics break that intuition. Each additional pound of revenue in a positive-CCC business requires its own slice of working capital to be committed before the cash comes back. Double your monthly sales, and (holding CCC constant) you roughly double the working capital tied up at any given moment — a genuine, quantifiable cash requirement that a P&L-only forecast misses entirely.

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Modelling working capital in your visa financial model

For most early-stage service or SaaS businesses on standard invoicing terms, a simplified approach is sufficient: estimate your realistic DSO from comparable UK businesses in your sector (not from an optimistic "customers pay on time" assumption), assume a defensible DPO based on your actual supplier terms, and build the resulting working-capital requirement into your monthly cash-flow forecast as an explicit line — not folded silently into "operating costs."

For a business with inventory or physical goods, DIO needs the same treatment: how long stock realistically sits before selling, based on your actual sales velocity assumptions rather than an idealised turnover rate.

The output belongs directly in your cash flow statement and feeds your runway calculation — a business with a 15-day positive CCC needs meaningfully more evidenced capital at scale than an equivalent business collecting cash upfront, even with identical revenue and profit forecasts.

What to watch for as you scale

Working capital needs typically shift as a business matures. Early customers, often smaller and more flexible, may accept faster payment terms; larger enterprise customers won as the business scales frequently demand longer terms (60-90 days is common), which can push DSO upward at exactly the moment revenue is accelerating. Model this shift explicitly in years two and three rather than assuming your initial payment terms hold at every size of customer.

Key takeaways

Profit and cash are different measures — a profitable, growing business can still run out of cash purely due to payment-timing mismatches.
The cash conversion cycle (DIO + DSO − DPO) quantifies how many days of working capital a business needs at any given revenue level.
Growth increases the absolute working capital requirement in any business with a positive cash conversion cycle — bigger wins can create bigger cash gaps.
Prepaid or subscription-upfront revenue models generate working capital rather than consuming it, which is structurally easier to fund.
Build working capital into your monthly cash-flow forecast as an explicit line, and revisit your DSO assumption as larger customers with longer payment terms enter the mix in later years.