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Posted: Mon 3rd Aug 2026
Last updated: Mon 3rd Aug 2026
21 min read
Cash flow is the money moving in and out of your business.
Money comes in when customers pay you, a loan lands in your account, a grant is paid or you receive a refund.
Money goes out when you pay suppliers, staff, tax, rent, software, stock, loan repayments or any other business cost.
Sounds simple. But the part that catches many businesses out is timing.
You can be making sales, winning work and looking healthy on paper, while still struggling to pay your bills. That often happens because money has to leave before enough money has arrived.
This guide explains what cash flow means, why it's so important and how to start keeping track of it.
Cash flow is the movement of money into and out of your business over a period of time.
In this context, "cash" usually means money available to the business, not physical notes and coins.
For most small businesses, that means the balance in the business bank account and any money that's actually available to spend.
The word "flow" is relevant because cash doesn't sit still. It arrives at certain points and leaves at others.
A sale only helps your cash position once the customer has paid. An invoice you've sent is useful, but it won't cover a bill due tomorrow unless the money has reached your account.
For example, you might invoice a client for £2,000 today. They have 30 days to pay.
But this week, you need to pay £900 in rent, software and suppliers' costs. Until that client pays, the £2,000 doesn't help with the immediate pressure.
That's why cash flow is so important. It shows whether you have enough money available when you need it.
Cash flow has two basic parts – money coming in (inflows) and money going out (outflows).
Cash inflows are payments coming into the business. These might include:
customer payments
deposits or staged payments
grants
loans
investment
VAT refunds
insurance payouts
money from selling equipment or other assets
Sales and cash inflows aren't always the same thing.
If you sell a product and get paid immediately, the sale creates cash straight away. If you send an invoice and wait 30 days, the sale has happened but the cash hasn't arrived yet.
That gap is often where cash flow problems begin.
Cash outflows are payments leaving the business. These might include:
rent
stock costs
wages
freelancer costs
supplier bills
tax
insurance
subscriptions
equipment costs
loan repayments
marketing costs
owner drawings
Some costs are easy to spot because they're large. Others are easy to ignore because they're small and regular.
A few software subscriptions, insurance instalments and card processing fees can add up quickly, especially when income is irregular.
Good cash flow management starts with seeing both sides clearly. What's coming in, what's going out and when each payment is expected to happen.
A business has positive cash flow when more money comes in than goes out during a set period.
For example, if £6,000 comes into your business in May and £4,800 goes out, your business has positive cash flow of £1,200 for that month.
Positive cash flow can give you more room to breathe. It may help you build a cash reserve, pay bills more comfortably, invest in equipment or handle a quieter month without relying on credit.
But it still needs context.
Your business can have positive cash flow in one month because it's received a loan, delayed paying its suppliers or collected several overdue invoices at once.
That doesn't automatically mean the business is profitable or financially strong long term.
A business has negative cash flow when more money leaves than comes in during a set period.
For example, if £5,000 comes into your business in June and £6,400 goes out, your business has negative cash flow of £1,400 for that month.
Negative cash flow isn't always a disaster. It can happen when you invest in equipment, buy stock ahead of a busy period or wait for customers to pay.
The risk grows when negative cash flow is unexpected, occurs repeatedly or unsupported by enough money in reserve.
Imagine a small design business starts the month with £3,000 in its bank account.
During the month, it receives £4,000 in client payments and a £500 deposit for a new project. Total cash coming in is £4,500.
It also pays £1,200 for workspace costs, £800 for software and subscriptions, and £1,500 for freelance support. It sets aside £700 for tax and £600 in owner drawings. Total cash going out is £4,800.
So the cash flow for the month looks like this:
Opening cash balance: £3,000
Cash in: £4,500
Cash out: £4,800
Net cash flow: –£300
Closing cash balance: £2,700
The business still has money in the bank at the end of the month. But the month itself was cash flow negative. If the same pattern continues, that £3,000 starting balance will keep falling.
The basic calculation is:
Opening cash balance + cash inflows - cash outflows = closing cash balance
That simple formula tells you a lot. It shows whether your cash position is improving, shrinking or staying steady.
Cash flow affects what your business can do day to day. It shapes whether you can pay bills on time, take on new work, invest in growth or handle a quiet spell.
It also affects how much control you feel you have.
When you're not clear on your cash flow, you start making reactive decisions. You may pay suppliers late, put costs on a credit card or avoid looking too closely at your bank account.
When cash flow is easy to see, you can make decisions earlier. That might mean chasing invoices sooner, changing payment terms, holding back on a purchase or speaking to a lender before there's a serious problem.
Cash flow also matters because many business costs are predictable, even when income isn't.
Tax bills, insurance renewals, VAT payments, rent, wages and loan repayments all arrive at fixed points.
If you haven't set money aside, those predictable costs can still put you under some pressure.
Growth can make the issue more pronounced. A growing business may need to spend more before the extra income arrives.
You might buy more stock, take on staff, invest in marketing or cover larger project costs upfront. Sales may rise, but the bank balance can still feel tight.
That's why cash flow isn't only a concern for struggling businesses. It matters just as much when things are going well.
Cash flow and profit are connected, but they measure different things.
Profit shows whether your income is higher than your costs over a period.
Cash flow shows when money actually enters and leaves the business.
A business can be profitable and still run short of cash.
Say you make £10,000 in sales this month and your costs are £7,000. On paper, that gives you £3,000 profit. But if most customers haven't paid yet and your suppliers need paying now, you may still struggle to cover the week's bills.
This happens more often than people expect. Profit matters, but on its own it won't tell you whether you can pay the bills due next week.
For more detail, read our guide to why profitable businesses can still run out of cash.
It's easy to mix up cash flow, turnover and profit. They're all useful, but each one tells you something different.
Cash flow: Money moving in and out of the business.
Example: A client pays your invoice and you pay a supplier.
Turnover: Total income from sales before costs are deducted.
Example: You sell £80,000 worth of products in a year.
Profit: What's left after costs are deducted from income.
Example: You make £80,000 in sales and have £55,000 in costs, leaving £25,000 profit.
Turnover shows the scale of your sales. Profit shows whether the business is making money after costs. Cash flow shows whether enough money is available at the right time.
A business can have high turnover and poor cash flow. It can also make a profit and still feel short of money if payments are delayed or costs fall at awkward times.
Several things can put pressure on cash flow. Some are obvious. Others are easy to miss until the bank balance starts to fall.
This is one of the biggest factors. If customers pay late or your payment terms are long, you may end up funding the work before you're paid for it.
A 60-day payment term can feel manageable when everything else is steady. It feels very different when rent, wages or supplier bills are due now.
Asking for payment upfront, taking deposits or billing in stages can improve cash flow. Waiting until the end of a long project to invoice can leave the business carrying costs for weeks or months.
Rent, subscriptions, salaries, insurance and utilities keep leaving the account whether sales are strong or quiet. Fixed costs need close attention because they give you less room to manoeuvre.
If you buy stock before selling it, that cash is tied up until customers pay. Too much stock can leave you short of available money, even if the products are likely to sell later.
This is another common pressure point. VAT, Corporation Tax, PAYE and Self Assessment bills can create problems if you haven't set the money aside.
The issue is rarely that the bill is a surprise. It's that the cash has been used elsewhere by the time the payment is due.
Some businesses earn most of their income during particular months. Others have predictable dips during summer, January or school holidays.
Cash flow planning helps you get through those quieter periods without treating each one as a shock.
Larger orders, new staff, equipment, premises and marketing can all take cash out before the return comes in. Growth is often good news, but it still needs funding.
Cash flow problems usually give you warning signs before they become serious.
You might find yourself checking the bank balance more often, delaying payments to suppliers or using personal money to cover business costs.
You may be relying on an overdraft or credit card for normal bills, not just occasional costs.
Other signs include:
chasing overdue invoices more often
struggling to set money aside for tax
avoiding your accounts because they feel unclear
taking on new work while still feeling short of cash
None of these signs means the business is failing. But they do tell you that you need a clearer view of what's coming in, what's going out and what decisions you need to make.
The earlier you spot a cash flow issue, the more options you have.
You can chase payments, lower costs, renegotiate terms, delay non-essential spending or arrange finance with a clearer plan.
Tracking cash flow is pretty easy. A spreadsheet, accounting software or a simple template can all work. The main thing is to make the movement of money visible.
Start with your current cash position. Look at the money actually available in your business account. Don't include invoices sent unless they've been paid.
Then list the money you expect to come in. Include invoices due, confirmed customer payments, deposits, approved grant payments or loan funds that are definitely on the way. Be honest here. Hopeful income can make the picture look better than it is.
Next, list the money due to go out. Include supplier bills, rent, wages, tax, subscriptions, loan repayments, stock, materials and planned purchases.
Then look at timing. This is the part that matters most. A payment due in six weeks won't help with a bill due tomorrow. A strong sales month won't solve a cash shortage if customers pay long after your own costs are due.
If money is tight, review your cash flow weekly. If things are steadier, a monthly review may be enough. But don't wait until there's a problem to look.
For a more structured approach, read our guide to creating a cash flow forecast for your small business and download our cash flow forecast template.
Improving cash flow usually starts with small, practical changes.
Invoice as soon as the work is complete, or at agreed stages during the project. Make payment terms clear before work begins. Don't wait too long to chase overdue invoices. A polite reminder sent early is easier than a difficult conversation months later.
Deposits can also help, especially for project-based work or larger orders. They reduce the amount you have to fund upfront and give you some protection if a customer delays or cancels.
It's also worth reviewing your costs. Look at subscriptions, supplier terms, stock levels, insurance and regular payments. Some costs may still be useful, but others may no longer earn their place.
Pricing affects cash flow too. If your prices are too low, the business may stay busy while still struggling to build enough cash. That's a hard position to sustain.
Tax needs its own attention. Setting aside money as income arrives can stop tax bills from turning into cash flow shocks. A separate savings account can help, even if you start with a rough percentage and refine it later with your accountant.
Finance may be useful in some situations, but borrow with care. Borrowing to cover a short timing gap can make sense if you know when money is coming in and how you'll handle the repayments. Borrowing to cover repeated cash shortages without fixing the cause is more risky.
For more practical steps, read our guide to improving cash flow quickly.
A cash flow forecast is an estimate of the money you expect to come in and go out over a future period.
It helps you see whether you're likely to have enough cash to cover upcoming costs.
It can also show when a shortfall might happen, which gives you time to act before the pressure becomes urgent.
A forecast usually includes:
opening cash balance
expected income
expected payments out
net cash flow
closing cash balance
Some businesses use a weekly forecast for the next 13 weeks. Others use a monthly forecast for the next year. The right format depends on how predictable your income and costs are.
If cash is tight or payments are irregular, a weekly forecast gives you a closer view. If the business is stable, a monthly forecast may be enough for normal planning.
A forecast won't be perfect. It will change as customers pay, costs shift and new work comes in. That's fine. The value comes from keeping it updated and using it to make better decisions.
For more on forecasting, read our guide to creating a cash flow forecast and download our cash flow forecast template.
VIDEO: A guide to cash flow forecasting
Adele Kilbane and Sean Hackemann share their insights on how to get to grips with cash flow forecasting. Learn about managing your short-term cash flow and preparing your business for the future:
A cash flow statement is a financial report that shows how cash moved through a business over a past period.
It's different from a forecast. A forecast looks ahead. A cash flow statement looks back.
Typically, you use accounting software to prepare a formal cash flow statement, or an accountant does it for you.
The statement usually groups cash movement by the type of activity, such as day-to-day trading, investment in assets and finance from loans or investors.
Many small business owners won't need to prepare a formal cash flow statement themselves.
But the basic idea is still useful. It helps you understand where cash came from, where it went and how your cash position changed.
Cash flow becomes easier to manage when it becomes part of your normal routine.
Check your bank balance alongside upcoming payments, not on its own.
Send invoices promptly.
Keep payment terms visible on quotes, contracts and invoices.
Review overdue payments before they drift too far.
It also helps to keep tax money separate where possible, even if the amount is only an estimate at first.
Review recurring payments every few months.
Update your forecast when a customer pays late, a cost changes or you take on a larger piece of work.
The point of all this work is to avoid running the business from a bank balance that only shows what's true today.
Cash flow is the money coming into and going out of your business. It shows whether you have enough money available to pay costs when they fall due.
A customer paying an invoice is cash flowing into the business. Paying rent, wages, tax or a supplier is cash flowing out.
No. Profit shows whether income is higher than costs over a period. Cash flow shows when money actually enters and leaves the business.
Yes. A profitable business can run short of cash if customers pay late, costs are due before income arrives, too much money is tied up in stock or large payments are due at awkward times.
Common causes include late payments, long payment terms, high overheads, seasonal sales, unexpected costs, tax bills, poor pricing and growth that needs funding before extra income arrives.
If money is tight or payments are irregular, check it each week. If the business is more stable, a monthly review may be enough. Upcoming bills and overdue invoices still need regular attention.
Start with a simple spreadsheet or cash flow forecast template. List your opening balance, expected money in, expected money out and closing balance for each week or month.
