How much cash cushion does your business need?

A business can be profitable on paper and still run out of money. Profit is what's left after expenses on your income statement. Cash cushion is what's sitting in your account when a slow month, a late-paying client, or an unexpected repair shows up at the same time. Businesses don't usually fail because they weren't profitable. They fail because they ran out of cash while waiting for profit to show up as money in the bank.

Why profit and cash aren't the same thing

Your profit and loss statement can show a strong month even while your bank balance drops, because revenue gets recorded when it's earned, not when it's collected. A $20,000 invoice sent in March that doesn't get paid until May looks like March income on your books, but it's May cash in your account. Stack a few of those timing gaps together, layer in a slow season, and a genuinely profitable business can still come up short on the one thing that pays the bills: cash on hand.

The rule of thumb, and why it's just a starting point

The standard guidance is three to six months of operating expenses held in reserve. It's a reasonable starting point, but it's not a real answer until you know where your business falls in that range, and for some businesses, even six months isn't enough. The right number depends on your specific risk factors, not a generic rule.

What determines your number

• Revenue predictability. A business with steady monthly recurring revenue can run leaner than one with lumpy, seasonal, or project-based income.
• Customer concentration. If one client makes up 40% of your revenue, losing them is a real scenario you need to be able to survive, not a remote possibility.
• Fixed versus variable costs. Rent, payroll, and insurance don't pause when revenue slows. A business with high fixed costs needs a bigger buffer than one that can scale expenses down quickly.
• Payment terms and collection lag. A business that gets paid on delivery needs less cushion than one waiting 30 to 60 days on invoices, because the gap between doing the work and getting paid for it is itself a cash flow risk.
• Growth stage. A business reinvesting heavily or carrying debt payments has less flexibility to absorb a bad month than one that's stable and mature.

How to calculate your target number

Start with your monthly operating expenses, not your revenue. Cushion exists to cover what you owe when income slows down, so it's the expense side of the ledger that matters.

A business with this expense structure, moderate customer concentration, and 30-day payment terms might reasonably target four months of cushion: $18,000 × 4 = $72,000. A business with higher customer concentration or seasonal revenue might target six months instead, or $108,000. The math is simple once you know your monthly number and your risk profile. Getting the risk profile right is the part that takes an honest look at your specific business.

Where to keep it

Cash cushion works best in a separate business savings account, not sitting in the same checking account you run daily operations from. Keeping it separate does two things: it earns a bit of interest instead of none, and it removes the temptation to treat it as available float when checking gets tight. If it's visible and mixed in with operating cash, it gets spent. If it's set apart, it stays a cushion.

Building it if you don't have it yet

Few businesses start with a full cushion sitting in reserve. Build toward it the same way you'd build any savings goal: start with one month's expenses as the first milestone, and automate a percentage of revenue, 5% to 10% is a reasonable starting range, into the reserve account with every deposit. Revisit the target each quarter as your expenses, customer base, and risk profile change. A cushion that was right for your business two years ago may not be right for it now.

Want to calculate your own target?

The Cash Cushion Calculator in the Prism resource library walks through the same expense worksheet and risk factors above, with blank fields so you can land on your own number.

Want help figuring out your number?

A Vibe Check is a free, no-pressure conversation where we can look at your actual cash flow and help you set a target that fits your business, not a generic rule. Schedule yours here.

Keep reading

• Understanding your numbers: what your P&L actually tells you: the difference between profit and cash flow, explained from the ground up.
• Reconciling your bank account: the one habit that catches everything else: the habit that keeps your cash numbers accurate enough to plan around.

This post is general information, not advice for your specific situation. The right cash cushion depends on your industry, growth stage, and risk tolerance. Talk to a financial advisor or bookkeeper about what fits your business.