A single slow month, a late-paying client, or an unexpected repair shouldn't be enough to put a business in crisis mode — but for a lot of small businesses running lean, it is. A cash reserve is what turns those moments from emergencies into non-events, and building one is more straightforward than most owners assume.
How much is actually enough
A common starting target is three to six months of fixed operating expenses — rent, insurance, minimum payroll, core subscriptions — sitting in a separate account you don't touch for day-to-day spending. Seasonal businesses, or ones with less predictable revenue, generally sit closer to the higher end of that range.
Why it needs to be separate from your operating account
A reserve that lives in the same account as everyday cash flow tends to quietly get spent — not through any single bad decision, just through the normal drift of day-to-day spending. A dedicated, separate account makes the reserve something you consciously decide to draw from, rather than something that erodes without anyone noticing.
How to actually build it without straining operations
Treat the contribution like a fixed expense, not a leftover. A consistent transfer — even a modest one — after each deposit or each month builds the reserve steadily, and is far more reliable than "whatever's left over," which for most businesses is close to nothing most months.
What a healthy reserve changes
Beyond covering emergencies, a solid reserve changes how you make decisions — you can take a slow month, a client who pays late, or a seasonal dip without panicking or reaching for a high-interest credit line. It's the practical companion to a cash flow forecast: the forecast tells you a gap is coming, and the reserve is what actually covers it.
Not sure how big your gaps actually run, or how close you already are to a healthy reserve target? Our free cash flow calculator is a fast way to check. And if slow-paying invoices are part of what's making cash tight in the first place, that's worth fixing alongside the reserve, not instead of it. S&C Bookkeeping can help build both the forecast and the plan to fund it — get in touch to get started.