How much cash should a business have in reserve?

As a business, there’s every possibility you could face an unexpected financial setback, whether that’s a dip in sales, broken equipment or a late-paying customer. Having enough cash available to absorb those shocks can be the difference between a manageable problem and a genuine cash-flow crisis.

But how much should a business actually keep in reserve?

There is no single figure or percentage that works for everyone. A better question is: how much cash would your business realistically need to survive a difficult few months?

The answer depends on your overheads, payment terms, tax liabilities, revenue predictability and the level of risk within the business.

What is a cash reserve?

A cash reserve can be confused with everyday working capital, but they are not the same. Instead, a cash reserve is money deliberately retained within the business to cover future costs, unexpected events, and temporary reductions in income. This gives a business time to respond to a problem, rather than forcing them to make decisions under pressure.

Before calculating your reserve, distinguish between genuinely available cash and money already committed to known liabilities. Cash set aside for VAT, PAYE, Corporation Tax, payroll or upcoming supplier payments shouldn’t normally be counted as part of your emergency reserve.

The traditional approach to business cash reserves

Many businesses use a traditional approach of keeping enough cash to cover three to six months of essential operating costs. However, this is only a general starting point. There is no universal formula for deciding how much cash to keep in reserve.

The following section outlines the factors that can determine how much cash should be kept in your business’s reserve.

A simple starting calculation

Start by identifying your essential monthly cash outgoings - payroll, rent, finance commitments, utilities, software, insurance and other costs you couldn’t quickly remove.

If these total £25,000 per month, a three-month starting reserve would be £75,000 and a six-month reserve would be £150,000.

From there, adjust the figure for the risks specific to your business. A company with recurring monthly income and a diverse customer base may be comfortable towards the lower end, while a seasonal business with long payment terms and high fixed costs may need considerably more.

Factors that shape your cash reserve

To help understand the right ballpark for your business, consider:

• Revenue predictability: Recurring or contracted income. This includes retainers, subscriptions, and long-term contracts, all of which can support a leaner reserve than lumpy, seasonal, or project-based revenue.
• Payment terms: If your industry typically operates on 90-day terms, a 3-month reserve may not withstand a single round of invoice delays. The longer and less reliable your payment terms, the larger your buffer needs to be.
• Fixed cost burden: High payroll, rent, or leased equipment costs require a larger cushion than a lean, variable-cost business, where spending can be quickly reduced if necessary.
• Customer concentration: If two or three clients make up most of your revenue, losing one is a much bigger shock than it would be for a business with a diverse client base, and your reserve should reflect that risk.
• Growth plans and risk appetite: A business planning to hire or invest in the next 6-12 months needs reserves that go beyond pure survival and can fund other initiatives or expansions when required.

Signs you don’t have enough cash in reserve

If you’re still not sure whether you have enough cash in reserve, your day-to-day finances will usually help you. Watch out for these signs that you’re under-saving:

• You’re anxiously checking the bank balance before every payroll run, even when your business is “profitable” on paper.
• One late payment can trigger a genuine cash-flow emergency, not just a manageable inconvenience.
• You rely on credit for routine gaps. For example, you use an overdraft or credit card to cover normal operating costs, not just for a one-off investment.
• VAT, Corporation Tax, and PAYE liabilities catch you off guard because you have already set aside cash elsewhere.
• You find yourself turning down good opportunities, not because they’re wrong, but because there's no room to absorb short-term cash strain.
• You’re regularly drawing down your buffer just to get through routine months.

If you regularly experience any of these situations, we strongly recommend revisiting your cash runway and overall budgets versus reality. A cashflow forecast is a useful tool for providing visibility and predictability here.

Signs you’re holding too much

Too little cash creates risk, but retaining excessive amounts without a purpose can be inefficient too. You might be holding too much cash if:

• You have large balances that sit idle for years, earn minimal interest, and lose value to inflation.
• You miss reinvestment opportunities, meaning competitors end up scaling faster by deploying capital you’re sitting on.
• You’re unsure about how much is actually “spare” versus already set aside for tax, payroll, or known upcoming costs.

Regular analysis of your financial performance and cash flow can help you find the sweet spot between cash retention and investment. Finding this balance is crucial for companies on a growth trajectory – one of many ways regular Management Accounts deliver real value.

Where should you keep your cash reserve?

Your cash reserve should be accessible when you need it but kept separate so you don’t accidentally spend it as part of day-to-day cash flow. Practical options include:

• Business Savings Account: Easy access and basic interest. Avoid using a personal account, as merging business and personal funds can quickly become messy and error-prone.
• Fixed-term savings account: They have slightly better interest rates in exchange for reduced flexibility.
• Instant access business savings apps: They’re useful for automating the habit, with scheduled transfers keeping the reserve topped up while still allowing quick access if needed.

Whichever route you choose, make sure the account is held in the business’s name and check that your deposits are eligible for protection under the UK’s Financial Services Compensation Scheme (FSCS). From 1 December 2025, eligible deposits are generally protected up to £120,000 per eligible depositor, per UK-authorised firm. Be aware that different banking brands can sometimes share the same banking licence.

Final considerations

No single cash reserve figure suits every business.

A common benchmark of keeping 3-6 months of operating expenses in reserve is a reasonable starting point, but it’s not a strategy on its own. True financial resilience comes from a reserve that is built around your specific business, not a number borrowed from someone else’s.

A reserve should give you the time to respond to potential problems calmly, rather than being forced into rushed decisions when something goes wrong.

If you can’t currently say what your cash reserve target is - or explain why it’s set at that level - that’s a good place to start. If you need help understanding your cash position, building a cash flow forecast, or deciding what an appropriate reserve looks like for your business, we’re happy to help.