Petty Cash Management: The Complete Guide for Australian Businesses

Every office has a tin somewhere. A small float for parking meters, printer cartridges, the occasional team lunch. But without a clear petty cash management system in place, that tin quietly becomes a source of missing receipts, unreconciled balances, and GST claims your accountant can't touch.

This guide covers everything your business needs to run petty cash properly, from setting up the float to meeting ATO record-keeping requirements, and explains when it makes sense to move beyond the tin entirely.

What Is Petty Cash?

Petty cash is a small amount of physical cash kept on hand to cover minor, everyday business expenses, the kind that are too small or too inconvenient to put through a formal purchase order or company card. Think: postage, office supplies, cab fares, or a box of pens from the corner shop.

Most Australian businesses keep a petty cash float between $100 and $500, though the right amount depends on the size of your business and how frequently your team needs it. Larger organisations with multiple departments may maintain several separate floats.

The imprest system

The most common and reliable way to run petty cash is the imprest system. Under this method, the float is set at a fixed amount, say, $300. Every time cash is taken out, a receipt or voucher goes in to replace it. The total of cash remaining plus receipts held must always equal the original float.

When the float runs low, it is replenished by exactly the amount spent, verified against receipts , bringing it back to $300. The float never grows beyond its set amount, which keeps spending controlled and reconciliation straightforward.

What Is Petty Cash Management?

Petty cash management is the process of controlling, recording, reconciling, and accounting for all transactions made through a petty cash float. It covers:

• Who is authorised to access and disburse cash
• What expenses are allowable
• How disbursements are recorded and receipts collected
• How the float is reconciled and replenished
• How transactions are posted to your accounting system
• How records are retained to satisfy ATO requirements

Done well, petty cash management gives your finance team complete visibility over a small but often poorly-tracked category of spend. Done poorly, it creates gaps in your books, opens the door to petty fraud, and costs you at BAS time.

How to Set Up a Petty Cash System

Getting your petty cash system right from the start takes less than an hour. Here is how to do it properly.

1. Define the float amount

Decide how much cash to keep on hand. $100-$300 is typical for a small business; $300-$500 for a team with regular incidental expenses. Keep it as low as practical, large floats invite larger problems.

2. Appoint a petty cash custodian

One person should own the float. The custodian is responsible for holding the cash securely, issuing funds against receipts, maintaining the log, and initiating replenishment. This is usually an office manager, finance assistant, or senior administrator.

Only the custodian should have access to the cash box. Shared access removes accountability.

3. Set up a petty cash log

Every disbursement must be recorded. Your log should capture:

• Date of the transaction
• Amount disbursed
• Purpose / expense description
• GST amount (if applicable, see below)
• Name of the person who received the cash
• Receipt number or reference

A simple spreadsheet works fine. Some businesses use a pre-numbered petty cash voucher for each transaction, which makes auditing cleaner.

4. Set spending limits and allowable categories

Define a per-transaction cap, $50 is a common ceiling. Anything above this should go through a purchase order, company card, or reimbursement process instead.

List the expense types petty cash can cover: office supplies, minor postage, small equipment items, refreshments for meetings. List what it cannot cover: alcohol, personal expenses, travel without prior approval.

5. GST on petty cash

Petty cash is not exempt from GST obligations. If your business is registered for GST, you can claim GST credits on petty cash purchases, but only if you have a valid tax invoice for each purchase over $82.50 (including GST).

For purchases $82.50 or under, you can still claim a GST credit without a tax invoice, but you must have some form of receipt or written record showing the amount paid and that GST was included.

Keep this distinction clear in your log. Expenses recorded without adequate documentation cannot be claimed as GST input tax credits on your BAS.

6. Secure the float

Store petty cash in a lockable cash box in a secure location. Access is limited to the custodian. When not in use, the box should be locked and stored in a locked drawer or safe.

How to Reconcile Petty Cash

Reconciliation confirms that your float is intact and all disbursements are accounted for. Reconcile at least monthly, weekly if your float turns over quickly.

The reconciliation formula:

Cash on hand + Total receipts held = Opening float

If the numbers do not match, you have a discrepancy. This could mean:
- A receipt is missing
- Cash was disbursed without being recorded
- An entry error in the log

Track down the discrepancy before replenishing the float. Recurring small shortfalls are a red flag for petty theft.

To replenish:

1. Total all receipts since the last replenishment
2. Write a cheque or transfer exactly that amount to the float
3. File the receipts against the replenishment entry in your accounting system
4. The float returns to its opening amount

Post the replenishment entry as a debit to the relevant expense accounts (stationery, postage, etc.) and a credit to the bank account used to fund the float.

ATO Requirements for Petty Cash

Australian businesses must meet specific record-keeping obligations for petty cash. Getting this wrong means potential problems at audit and lost GST credits.

Record-keeping

Under the ATO's record-keeping rules, all business expense records, including petty cash vouchers, receipts, and cash books , must be kept for five years from the date of the transaction or the date the record was prepared (whichever is later).

Records must be in English (or readily convertible to English) and must clearly show the nature of the expense, the amount, and the date.

GST and tax invoices

To claim a GST credit on your BAS:
- Purchases over $82.50 (GST-inclusive): a valid tax invoice is required
- Purchases $82.50 or under: a receipt or other written record showing the amount and that GST was included is sufficient

If you cannot produce the required documentation at BAS time, you cannot claim the credit. This is one of the most common petty cash errors at audit.

FBT considerations

If petty cash is used to pay for items that could be classified as fringe benefits, for example, meals or entertainment that are not exempt minor benefits, there may be FBT implications. The ATO's minor benefits exemption applies to benefits valued under $300 (GST-inclusive) where the benefit is infrequent and irregular. Regularly using petty cash for team meals could breach this threshold over time.

If you are unsure whether a petty cash expense has FBT implications, record it clearly and check with your accountant before lodging.

Common Petty Cash Problems

Most petty cash problems are predictable. Here is what to watch for.

No custodian accountability. When everyone can access the tin, no one is responsible. Losses are untraceable and your books are perpetually wrong.

Missing receipts. Cash goes out; nothing comes back. No receipt means no GST claim and no audit trail. Enforce a strict "no receipt, no cash" rule.

Float not reconciled. Weeks pass without a count. By the time someone checks, the discrepancy is so large it is impossible to identify the source. Monthly reconciliation is the minimum.

Float amount is too large. A $1,000 float for a small team is an invitation to misuse. Keep the float size proportionate to actual monthly spend.

Petty cash used for the wrong things. Larger purchases pushed through petty cash to avoid the procurement process. Clear category limits prevent this.

No separation of duties. The person who disburses cash also reconciles the float. In any well-run finance function, these roles should be separate where possible.

When Businesses Move Beyond Petty Cash

Petty cash works well when spend is genuinely small, genuinely infrequent, and genuinely incidental. When those conditions stop being true, the system starts costing you more than it saves.

Businesses typically outgrow petty cash when:

• Multiple team members need access to funds at the same time
• Remote or field-based people need to make purchases without going back to the office
• The volume of transactions makes the manual log a full-time job
• GST capture becomes inconsistent and BAS time becomes painful
• The finance team is spending time chasing receipts instead of closing the books

Modern alternatives, corporate cards, virtual cards, and prepaid expense cards , give your team purchasing power without physical cash changing hands. Receipts are captured digitally at the point of purchase. Approvals happen before the spend occurs, not after. Accounting entries are automatic.

For many Australian businesses, this shift removes petty cash problems entirely rather than trying to manage around them.

How Weel Replaces Petty Cash for Australian Businesses

Weel gives your team a better way to handle the same expenses petty cash was designed for, without the tin, the log, or the end-of-month receipt hunt.

With Weel, every team member who needs purchasing ability gets a Weel card, physical or virtual , with a set spend limit and approved categories. When they make a purchase, they capture the receipt on the spot through the Weel app. The transaction, GST breakdown, and receipt are synced directly into your accounting system, typically within 2.3 days of the card being swiped.

There is no float to count, no manual reconciliation formula, and no end-of-quarter scramble for missing tax invoices. Every expense is complete, documented, categorised, and ready for your BAS.

For finance teams who manage approvals, Weel's approval workflows mean spend does not happen until the right person has signed off. Businesses using Weel approval workflows reach 95% expense completion: every expense accounted for, no gaps in the books.

Over 4,000 Australian businesses use Weel to close their books with confidence. For the office manager who used to own the petty cash tin, it means the chase is over.

Expense Pain, Gone.

Ready to close the tin? Book a free demo

Conclusion

Petty cash management is not complicated, but it does require clear rules, a single accountable custodian, and consistent reconciliation. Follow the imprest system, capture every receipt, meet ATO record-keeping obligations, and review your float size regularly.

If the volume or complexity of incidental expenses in your business has grown beyond what a cash tin can handle cleanly, the answer is not a bigger tin. It is a system that captures every expense automatically, keeps GST records intact, and gives your finance team full visibility without the manual work.