Guide · Cash flow

Building a cash buffer: how much is enough, and how to get there

A cash buffer is money your business sets aside to keep paying fixed costs through an unexpected shortfall. A practical starting target is one to three months of fixed costs, adjusted for how seasonal and concentrated your income is. You build it by moving a set share of receipts into a separate account, contributing hardest in your strongest months.

5 min readBy the Capital On Call Editorial TeamUpdated 28 September 2026
Aerial view over the curved bay and granite peaks of Wineglass Bay, Freycinet, Tasmania

Why does a cash buffer matter?

Most small business cash crises aren’t caused by losses. They’re caused by timing — a customer paying three weeks late, a quiet month running long, a refrigeration unit failing in January, a BAS larger than expected. A buffer turns those events from emergencies into inconveniences.

Timing pressure is a constant. Xero Small Business Insights data shows Australian small businesses waited an average of 22.9 days to be paid in the June 2026 quarter, with payments arriving six days late on average. And when Xero surveyed owners in March 2026 ahead of Payday Super, 87% said more frequent super payments would strain their cash flow, while 31% expected to dip into personal savings to keep up.

A buffer also gives you choices: taking a supplier’s early-payment discount, keeping good staff through a slow patch, or walking away from a bad deal because you don’t need the cash.

How much is enough?

There’s no single right number. A practical method is to start with fixed costs — what the business must pay even if sales stopped for a month:

  • Rent and outgoings
  • Core staff wages and the super that comes with them
  • Loan, lease and hire purchase repayments
  • Insurance, software, phones and utilities
  • The owner’s minimum drawings

Then choose a multiple that fits your risk:

Business profileSuggested starting buffer
Steady income from many customersAbout 1 month of fixed costs
Some seasonality, or a few large customersAbout 2 months
Strongly seasonal or highly concentrated income3 months, or enough to reach the next peak

These are starting points, not rules. A seasonal cash flow plan shows your actual lowest point, which is the most accurate way to size a buffer.

How do you build one?

1. Automate the transfer

Set up an automatic transfer of a fixed share of receipts — or a set amount each week — into a separate buffer account. Automation means it happens without relying on willpower in a busy week.

2. Save hardest in the peak

Seasonal businesses should build the buffer during their strongest months. A higher transfer from December to March for a summer tourism business, or during vintage for a contract picker, and little or nothing in the quietest months, matches saving to cash flow.

3. Bank the windfalls

A tax refund, an unusually large job, the proceeds from selling surplus equipment — send a portion straight to the buffer before it becomes everyday money.

4. Trim before you save

Review subscriptions, insurance, telco and supplier contracts once a year. Savings found there can go straight into the buffer without touching operations.

5. Separate tax money first

Your buffer is not your tax account. Set aside GST, PAYG withholding, any PAYG instalments and super in a separate account as money comes in. Under Payday Super from 1 July 2026, super is due within seven business days of each payday, so it needs to be ready every pay run — see our Payday Super guide. The buffer is built from what’s left.

Where should you keep it?

  • A separate business savings account — reachable within a day, not on your everyday card.
  • Not in stock or equipment. Assets you’d have to sell in a hurry aren’t a buffer.
  • Not in a term deposit you can’t break quickly, unless you’re holding more than you’d ever need at short notice.

What rules should govern using it?

A buffer only works if it’s used for the right things. Write your rules down:

  • Use it for timing gaps, genuine emergencies and urgent repairs.
  • Don’t use it for routine spending, discretionary drawings or propping up ongoing losses.
  • Always rebuild it after you draw on it, before any other discretionary spending.

How do a buffer and standby credit work together?

Even well-run businesses find it hard to hold three months of fixed costs in cash, especially while growing. That’s where a second layer helps.

Cash bufferStandby facility
Cost to holdOnly the return you give upDepends on the facility
SpeedInstantFast once it’s set up
SizeLimited by what you’ve savedBased on turnover
Best forSmall, frequent surprisesLarger or longer gaps

A standby line of credit, arranged while trading is healthy, lets you hold a smaller cash buffer without taking on more risk. Use the buffer first; draw on the facility only when a shortfall is bigger or lasts longer than the buffer can handle. Our guide to how a business line of credit works explains the mechanics.

What does this look like for a seasonal business?

Example scenario — illustrative only. A boat cruise operator on Tasmania’s east coast has fixed costs — wharf lease, three permanent crew and their super, vessel insurance, finance on the boat and the owner’s minimum drawings — of about $32,000 a month. From late May to September bookings cover only part of those costs, and the owner’s pessimistic forecast shows a winter shortfall of around $70,000.

The owner decides to hold about one month of fixed costs as a cash buffer, built by transferring a larger share of receipts between December and March, and to arrange a standby facility for the rest of the gap. The buffer carries the business through the first weeks of winter; the facility is there if the season starts late or the vessel needs unplanned work on the slip.

Which mistakes undo a buffer?

  1. Counting an overdraft as the buffer. A bank can reduce or withdraw an overdraft, often when you need it most.
  2. Mixing buffer and tax money. When the BAS arrives, the buffer disappears with it.
  3. Never rebuilding it. A buffer drawn on and not topped up is simply gone.
  4. Holding far too much. Large idle balances while the business carries expensive debt can be inefficient — review the level with your accountant.

If you need a backstop now

If your buffer isn’t yet where it needs to be, a facility can sit behind it. Unsecured lines of credit generally suit businesses trading six months or more, and property-secured loans of $20,000 to $1m suit larger one-off needs. Our 60-second enquiry is free and doesn’t affect your credit score. To see how a limit can wait in the background until a gap appears, read about standby working capital.

FAQ

Quick answers

Where should a business keep its cash buffer?

In a separate business savings account that you can reach within a day but that isn't linked to your everyday card. The separation stops it drifting into routine spending.

Is it better to repay debt or build a buffer?

Usually a bit of both. With no buffer at all, a small surprise can force rushed borrowing; holding lots of idle cash while carrying costly debt can also be wasteful. Your accountant can help you strike the balance.

Does a line of credit replace a cash buffer?

Not entirely. A buffer covers small surprises instantly and at no cost, while a line of credit covers larger or longer gaps. They work best as two layers.

Should tax money count as part of my buffer?

No. GST, PAYG withholding and super belong to the ATO and your employees' funds. Set them aside in their own account first, and build the buffer from what's left.

Planning is step one. Funding is step two.

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