Cash flow projection: a 2026 guide for UK businesses

A cash flow projection is an estimate of the cash your business expects to have coming in and going out over a set period, usually the next three to twelve months, so you can see whether you will have enough to cover what you owe. It only counts cash once it actually lands in or leaves your bank account, which is what makes it such a useful early warning system for gaps before they become a real problem.

With employer National Insurance contributions and the National Living Wage both having risen, and late payments still a daily challenge for many UK businesses, a static budget no longer cuts it. A rolling cash flow projection gives you time to adjust spending or line up funding before a shortfall actually hits.

What is a cash flow projection?

A cash flow projection looks ahead at the money moving through your business, month by month or week by week, so you can plan around it. It is easy to confuse with your profit and loss account, but the two measure very different things.

Your profit and loss account records a sale the moment you send an invoice. Your cash flow projection only records that sale once the client actually pays. If you offer 30 or 60 day payment terms, there is a real gap between doing the work and receiving the cash, and it is exactly this gap, alongside the timing of your own outgoings such as VAT, corporation tax and payroll, that a cash flow projection is built to capture.

Why cash flow projections matter

Businesses do not usually fail because they are unprofitable, they fail because they run out of cash at the wrong moment. A cash flow projection gives you sight of that risk well before it becomes urgent, so you can:

• Spot a cash shortfall weeks or months ahead, giving you time to act rather than react

• Time big spending decisions, such as hiring or buying equipment, around when the cash actually allows for them

• Back up a funding or investment application with solid, realistic numbers

• Decide when to chase a payment or renegotiate terms with a supplier

Cash flow projection vs cash flow forecast vs cash flow statement

These three terms get used loosely, and for most small businesses the distinction does not matter day to day. Used more precisely, each one answers a different question.

In practice, most businesses build one rolling document that does the job of both a projection and a forecast, using recent data as the starting point and then adjusting it to test different outcomes. For a closer look at short term planning, see our guide to cash flow forecasting.

What to include: cash inflows and outflows

A projection is only as good as the detail behind it. Before building one, list every source of cash movement in your business, not just the obvious ones.

Typical cash inflows include:

• Cash and card sales, and payments received from invoiced customers

• VAT refunds and other tax rebates

• Grants, government support schemes or investment received

• Money from selling old equipment or other assets

• Loan or overdraft drawdowns

Typical cash outflows include:

• Payroll, including employer National Insurance and pension contributions

• Rent, utilities and insurance

• Supplier and materials payments

• VAT, corporation tax and PAYE payments

• Loan repayments and interest

• Marketing, subscriptions and one off equipment purchases

Missing even one recurring outflow, such as a quarterly VAT bill or an annual insurance renewal, is one of the most common reasons a projection turns out to be wrong.

Two ways to build the numbers in a cash flow projection

There are two broad approaches, and the right one depends on how predictable your business is.

The quick method starts from one broad figure, such as expected annual sales, and spreads it across the months using simple assumptions. It is fast to put together and works well enough for stable businesses with little variation month to month, or for a new business without much history to draw on.

The detailed method builds the projection up from actual figures, such as confirmed orders, known payment dates and specific supplier invoices. It takes longer but is far more accurate, especially if your business is seasonal or your sales are unpredictable, since it reflects real timing rather than an average spread evenly across the year. A retailer with a strong Christmas period, or a builder working on long contracts, should build their numbers this way rather than dividing a yearly figure by twelve.

Many businesses mix the two, using the quick method for months further out and the detailed method for the next four to eight weeks, where accuracy matters most. You can build either version in a simple spreadsheet, or use accounting software that pulls in real invoice and bill data automatically to save time.

How to build a cash flow projection step by step

Building an accurate projection takes a disciplined look at your numbers and a realistic view of what is ahead. It is best to be conservative with income and thorough with costs.

• Choose your time period. Three months suits close cash management, while twelve months suits longer term planning and funding applications.

• Gather your historical data. Pull at least the last 12 months of bank statements, invoices and bills to see your typical payment timing and any seasonal patterns.

• Estimate your cash inflows. List expected sales using last year as a guide, adjusted for current trends, and include non sales income such as grants or tax refunds. Record everything based on when the cash actually arrives, not when the deal is signed.

• Map out your cash outflows. List every cost leaving the business, using the categories above, and factor in the current employer National Insurance rate and National Living Wage, since both have pushed up overheads this year.

• Work out your net cash flow and running balance. Subtract total outgoings from total income for each period, then carry the closing balance forward as the next period's opening balance.

• Revisit it often. Update a short term projection weekly and a longer one monthly, swapping assumptions for real numbers as they come in.

Worked example: a simple 3 month cash flow projection

Here is a simplified example showing how the numbers flow from one month into the next.

Notice how month 2 shows a dip even though sales were still healthy, because outgoings temporarily outpaced cash coming in, likely a quarterly bill or a larger supplier payment landing in the same period. Spotting a dip like this in advance, rather than after it hits your account, is the whole point of building the projection.

The 13 week rolling cash flow projection

While a 12 month view is useful for long term planning, many UK businesses find a 13 week rolling projection gives far better week to week control. It is a short, detailed projection covering roughly the next three months, updated every week as new figures come in.

Because it only looks a few months ahead, it tends to be far more accurate than a full year plan, and it is usually built using known invoices and confirmed payment dates rather than averages. It also makes it easy to see exactly how a late payment from one client will affect your ability to pay your own suppliers next month, so you can chase the debt or renegotiate terms before the gap actually opens up.

Planning for different outcomes

A cash flow projection is most useful when it covers more than one version of the future. It is worth building three:

• Base case. Your most likely outcome, based on current performance and known commitments.

• Best case. What happens if a contract lands early, a big client pays faster than expected, or costs come in lower than planned.

• Worst case. What happens if a key customer is lost, costs rise, or a major payment is delayed.

It is also worth testing what happens if your slowest paying customers take an extra two or four weeks to pay, since this alone can affect your cash position more than a change in sales. Having a worst case ready means you already know which costs you could cut and when you might need funding, rather than deciding under pressure.

Cash runway and cash tied up in the business

Two simple numbers help explain why your cash position moves the way it does. Cash runway tells you how many months your current cash balance would last if income stopped and your outgoings carried on as they are. It is a useful reality check, especially for newer or fast growing businesses that are not yet consistently profitable. The other is how long cash stays tied up in the business between paying for stock or materials and getting paid by your customers. The longer that gap, the more cash you need just to keep operating, which is exactly the kind of pressure a cash flow projection should flag well in advance.

How a cash flow projection supports your credit score and funding

Your cash flow management is one of the biggest factors behind your business credit score. Lenders and credit agencies look closely at how consistently a business meets its financial commitments, and a business that keeps a positive cash position and pays on time is viewed as lower risk. A clear projection also makes it easier to avoid missed payments or exceeding an overdraft limit, both of which can leave a lasting mark on your credit file. It also puts you in a stronger position when you do need to borrow, since lenders will often want to see a realistic projection as part of a funding application.

Common cash flow projection mistakes to avoid

• Being too optimistic about when customers will actually pay, the most common reason a projection turns out wrong

• Forgetting one off or seasonal costs, such as annual insurance renewals or quarterly tax bills

• Building the projection once and never updating it as real figures come in

• Ignoring the gap between invoicing and payment, especially where longer payment terms are offered

• Using one average figure spread evenly across the year when the business is genuinely seasonal

• Leaving no room in the numbers for a genuine worst case

Ready to put your projection into action?

Once your cash flow projection shows a gap ahead, having finance lined up in advance makes all the difference. At Capitalise, we work with a panel of 130+ lenders to help you compare business finance built around your numbers, from working capital loans to overdraft alternatives. Download our free cash flow forecast template to get started, then apply for funding, without affecting your credit score.