How much cash reserve should a business have? Count it in days

What businesses actually hold

The JPMorgan Chase Institute measured cash buffer days across 597,000 small firms using their bank transactions, which makes it the one study on this subject that is not a survey of what owners say. The median firm held 27 days. A quarter held fewer than 13. The 75th percentile held 62. And the number varied a lot by industry, which is the part the rules of thumb never mention.

Surveys point the same way. A March 2025 TD Bank study with Wakefield Research of 250 small business owners found 94 percent described themselves as financially prepared, and 19 percent had six or more months of operating costs saved. A June 2024 Xero survey of 1,021 businesses with 50 or fewer employees found 38 percent had an emergency fund at all. Whatever the right number is, most businesses are nowhere near six months, and most of them are still open.

Where three to six months comes from

SCORE's guidance, which most of the articles on the first page repeat, says three to six months and attributes it to "most experts". No study is cited. We could not find one. The Arkansas Small Business and Technology Development Center suggests one to two months. Both are reasonable for a business with one payroll, one bank account and steady receipts, and neither knows anything about yours.

The problem with a months-of-expenses target is that it is measured against the P&L, which is not what drains the account: payroll, loan principal, tax deposits and owner draws all leave the bank on fixed dates, and only some of them appear as expenses. So we would drop the months figure and count in days of outflow instead. It is the same unit the JPMorgan data uses, it comes from the bank rather than the books, and it can be computed per company.

Computing your own buffer days

Cash buffer days are the number of days a business could keep paying its bills at its recent rate if no money came in: the current bank balance divided by average daily cash outflows. Take the last 90 days of outflows from every business account, add them, divide by 90, and divide today's balance by the result.

One electrician, three companies: the electrical contracting business, a small maintenance-contracts company, and the LLC that holds the shop. Across all three, the bank accounts hold $196,500. Outflows over the last 90 days total $612,000, or $6,800 a day, so the group has 28.9 days of cash. That is almost exactly the median. It sounds fine until it is split by company.

The contracting company carries the payroll, $58,400 every other Friday, and its next large receipt is a $91,000 progress payment due in 22 days from a customer who runs about 20 days late. So the company that matters has 23 days of cash and roughly 42 days until it can count on a big deposit. The maintenance company and the property LLC have more than they need. Moving money between them is possible, and owners do it all the time, but every transfer is an intercompany loan or a distribution with a tax and lender consequence, and the bank that lent against the property will want to know why its cash went to the contracting business. The split is what shows the gap in July rather than in a September transfer.

How many days is enough

Four things set the number. Payroll cadence: a biweekly payroll means the largest outflow lands every 14 days, and the reserve has to cover at least one run plus whatever else falls in the same two weeks. Days sales outstanding: if customers pay in 45 days, a slow month shows up as a hole six weeks later, and the reserve has to bridge it. Seasonality: a landscaper in Minnesota needs a reserve going into November that a dental practice never does. And debt service dates: an annual insurance premium, a balloon payment or a quarterly tax deposit can take 15 days of cash out in one morning. Lay those against the 13-week cash flow forecast and the low week tells you the minimum. Add a margin for the receipt that slips, and that is your number.

For most 25-to-50-person businesses with biweekly payroll and ordinary collection terms, this works out to 30 to 60 days of outflow, which is more than the median and less than the advice. Restaurants live lower because customers pay on the spot. Contractors and anyone with 60-day terms live higher or borrow. The line of credit is the usual backstop, and the Federal Reserve's 2026 Small Business Credit Survey of 6,525 employer firms suggests it is less dependable than owners assume: 60 percent applied for financing, 42 percent received the full amount and 22 percent received none. What this method cannot do is size a reserve for a shock nobody has seen before; it sizes one for the gaps your own bank statements have already shown you.

The 82 percent claim

Nearly every article on this subject says 82 percent of business failures are due to cash flow problems. The figure is attributed to a U.S. Bank study, relayed by a consultant named Jessie Hagen, with no year, sample or method ever published. SMBcompass, a lender that tried to trace it in 2025, concedes it is "widely cited but rarely reproduced in detail". We do not use it, and we would not build a reserve policy on it.

What is published is less dramatic. Bureau of Labor Statistics survival data, cited in the same SMBcompass piece, shows about 20.4 percent of new businesses close within a year, 49.4 percent within five and 65.3 percent within ten. The Fed's 2026 survey found 56 percent of firms that sought financing wanted it to meet operating expenses, which is the closest thing to a measured statement that cash is the day-to-day problem. Cash is involved in most closures. How often it is the cause rather than the symptom, nobody has counted.

Where to hold it, and how to watch it

Keep the reserve in a separate account from the one that pays the bills, at the same bank if you want same-day transfers, in a savings or money market account if the balance justifies it. Common advice is to leave a cushion in the operating account so you never overdraw. We would keep the operating account lean and the reserve visible, because a cushion that sits in the operating balance gets spent by the third month without anyone deciding to spend it. And keep one reserve account per company, for the same reason each company has its own books: the money belongs to that entity, its lender may have a covenant on it, and the debt service coverage ratio the bank runs is calculated per borrower.

Then watch the number weekly rather than at the quarterly panic. Navigator's morning brief lists cash across every account and every company, read from QuickBooks Online each day, so the split above is in your inbox rather than in a spreadsheet; on the Pro plan the same figure sits against the 13-week forecast, which shows the days of cover to the low week rather than leaving you to compute them. The tiers are on the pricing page. What no report can do is tell you whether 30 days is enough for your customers; only your own collection history can, which is why tracing where last month's profit went is the place to start.

Questions owners ask

How many months of expenses should a business have saved?

The three-to-six-month figure is a rule of thumb with no study behind it. A better answer is the number of days of outflows that covers the gap between now and your next dependable receipt, plus a margin for that receipt slipping. For most 25-to-50-person businesses on biweekly payroll that works out to 30 to 60 days. Seasonal businesses need more going into the slow months.

Is 82 percent of business failures really due to cash flow?

Nobody can show you the study. The figure is attributed to a U.S. Bank study relayed by a consultant, with no year, sample or method ever published. The reliable numbers are the BLS survival rates: about 20 percent of new businesses close in year one and about half by year five. Cash is involved in most closures, but the 82 percent figure is not evidence of anything.

What is a cash buffer day?

One day of average cash outflow. Divide your bank balance by your average daily outflows over the last 90 days, and the result is how many days the business could keep paying at that rate if nothing came in. It is the measure the JPMorgan Chase Institute used across 597,000 firms, and it lets you compare your business with the median of 27 days.

Should each of my companies have its own reserve?

Yes, sized to each company's own outflows and lender terms, because cash in one entity is not available to another without a transfer that has tax and lender consequences. Compute buffer days per company as well as in total. A group with 29 days pooled can contain an operating company with 23 days and a payroll on Friday, which the pooled number hides.

Related

The reserve is the answer to a question the 13-week cash flow forecast asks every Monday, which is how low the account will go and when. If the reserve keeps shrinking while the P&L says you are profitable, why net income doesn't match your bank balance traces where it went. And if a bank is watching the same balance, debt service coverage ratio for business owners explains what it is looking for.

If you would like a second opinion on whether your books are current enough to count days of cash from, the free accounting health check is the place to start: navigatorhq.ai/health-check.

Published 16 Jul 2026. Last updated 16 Jul 2026. Reviewed by a CFO on the Navigator team.