Managing cash flow is boring, right up until you don’t have any.
And it’s usually something simple too; you pay out early, you get paid late, and the weeks in between are where your business quietly dries up. It’s not a sales problem, or a profit problem, yet plenty of businesses have gone under with a full order book and a healthy margin.
Here is how the gap opens up, how to calculate yours in days, and how to close it.
The gap, day by day
Day 1. You spend before you earn a cent. Your journey starts with an order. You place it with your supplier for the product you plan to sell. No cash has moved yet, but the clock has started. From here, everything is about timing.
Day 30. The goods arrive, along with the bill. Thirty days in, the goods land. Great. Except your supplier wants their piece. This is your first cash out moment, and it stings if you haven’t sold a single thing yet. Money leaves the building long before any comes in.
Day 50. You make a sale, but you’re still waiting. Twenty days later, you sell to your customers. Feels like the finish line. It is not. If you gave them 30 day payment terms, the cash is still a month away. You have a sale on paper and nothing in the bank.
Day 80. The cash finally lands. Your customers pay. The first real cash in since this whole thing began.
Now count it up. You paid your supplier on day 30 and didn’t see a dollar until day 80.
80 days or 50 days? The difference matters
Two numbers come out of that timeline and people mix them up constantly.
The cash conversion cycle is 80 days. That is the whole journey, from placing the order to the money landing.
The cash flow gap is 50 days. That is day 30 to day 80. The stretch where your money is gone and none of theirs has arrived.
The 50 is the number to care about, because that is the period you personally have to fund. Wages, rent, software and everything else keep going out the whole time, and none of it waits for your customer.
Your own gap might be shorter. It might be a great deal longer. It depends on your supplier terms, your customer terms, and how quickly people actually pay you, which is almost never as quickly as they said they would.
Work out your own gap
You do not need an accountant for this. Three numbers and one simple equation.
Cash flow gap (days) = days you hold stock + days your customers take to pay − days your supplier gives you
For the business above:
- Stock sits for 20 days (arrives day 30, sells day 50)
- Customers take 30 days to pay
- The supplier gives 0 days, it is due on delivery
20 + 30 − 0 = a 50 day gap
If you sell a service rather than a product, drop the stock number. Your gap is simply the time between doing the work and getting paid for it, minus whatever credit your own suppliers extend you. Most service businesses are surprised to find theirs sits between 45 and 75 days once late payers are counted honestly.
Turn your gap into a dollar figure
Days are abstract. Cash isn’t. Here is how to convert one into the other.
Work out what the business costs to run for a day, ignoring stock. For our wholesaler that is a founder wage, storage, software, marketing and insurance, roughly $5,950 a month, or about $196 a day.
Now multiply:
50 days × $196 = $9,800
Add the stock order itself, at $2,000, and this business needs somewhere around $11,800 sitting in reserve to survive one cycle. Not to grow. To survive.
That is the number to raise, borrow or bank before you launch, and it is the number most founders have never calculated. If your funding conversation currently sounds like “we probably need a hundred grand or so”, this is how you replace that with something you can defend. There is more on building the full picture in Everything Cash Flow Forecasting.
Two negotiations that shrink the gap
This is where it gets interesting, because the gap responds dramatically to small changes.
Start: supplier paid day 30, customers pay day 80. Gap: 50 days. Reserve needed: around $11,800.
Negotiate 30 day supplier terms. You now pay on day 60 instead of day 30. Nothing else changes. Gap: 20 days. Reserve needed: around $5,900.
Now shorten your customer terms to 14 days. They pay on day 64 instead of day 80. Gap: 4 days. Reserve needed: around $2,800.
Two conversations, neither of which costs you a cent in margin, and the cash you need to find drops by roughly nine thousand dollars. This is why payment terms are worth negotiating harder than price. A discount saves you a percentage. Better terms can save you the entire funding round.
Six ways to close the gap
Take payment up front where you can: Card at point of sale puts money in your account in a day or two rather than a month. Deposits on larger orders do the same job.
Negotiate longer supplier terms: Every extra day you hold their money is a day you do not need your own. Ask. The worst outcome is a no.
Shorten your customer terms: Thirty days is a convention, not a law. Fourteen is normal in plenty of industries, and new customers rarely push back on terms set at the start.
Chase overdue payments properly: A weekly overdue report and one named person who owns the follow ups. Not everyone’s job, which means nobody’s job.
Hold less stock: Every day stock sits on a shelf is a day of gap. Order smaller and more often, even if the unit price is slightly worse.
Keep a reserve and assume the worst: Always plan for cash landing later than promised, because it will. Sizing that buffer is part of the same thinking behind a one page business continuity plan.
Do this before you launch
So map your own day 1 to day 80. Work out when cash leaves and when it comes back. Multiply the gap by your daily running cost. Then fund the difference, and do it before you need it, because raising money while you are running out of it is the worst possible negotiating position.
While you are at it, check that your daily running cost includes everything. The costs founders forget are the ones that turn a manageable gap into a fatal one, and there is a list of the usual suspects in Hidden Costs in Business. If the fundamentals are still new to you, start with Startup Money 101, and if you want to pressure test what happens when a big customer pays late, that is squarely a risk management exercise.
Frequently asked questions
What is a cash flow gap?The number of days between paying your suppliers and being paid by your customers. During that window the business is funding itself out of reserves. Calculate it as days holding stock, plus days customers take to pay, minus days of credit your supplier gives you.
Is a cash flow gap the same as the cash conversion cycle?Close, but not identical. The cash conversion cycle usually measures the whole journey from placing an order to receiving payment. The cash flow gap measures only the part you have to fund, from cash going out to cash coming in. The gap is the smaller number and the more useful one.
What is a normal cash flow gap?It varies enormously by industry. Retail with card payments can run close to zero or even negative, because customers pay before suppliers do. Wholesale and B2B services commonly sit between 30 and 90 days. What matters is not whether yours is normal, but whether you have the reserve to fund it.
Stop guessing where your money goes
Gōru’s Cash Flow Forecast template maps your gap for you, down to the week. Punch in your numbers and find out what you are really working with.
Or start with the free simple version and read our full guide to building a forecast alongside it.
This article was originally published in June 2026 and last updated in August 2026 with a calculation method, worked scenarios and expanded guidance.
