Petty Cash Controls That Survive an Audit

Petty cash is the smallest amount of money in most businesses, and the hardest to account for. A hundred small payments, each too trivial to chase individually, add up to a sum that’s anything but trivial. Auditors know this. They look at petty cash first, because if your smallest system is sloppy, they assume your bigger ones are too. This article covers the controls that keep petty cash honest, accurate, and audit-proof.

Why This Matters

Petty cash problems are rarely dramatic theft. They’re usually a slow drift: a taxi fare without a receipt, a lunch claimed twice, a float topped up from the till without being recorded. Each instance is small enough to ignore. But the cumulative effect is a cash balance that never reconciles, a tax return with undocumented expenses, and, if you’re unlucky, an auditor’s finding that your financial controls are inadequate.

The stakes are higher than the amounts suggest. Tax authorities in most countries require documented evidence for business expenses; “miscellaneous cash” without receipts is routinely disallowed. If you ever sell the business or seek investment, due diligence will probe your cash controls. And internally, a well-run petty cash system is the clearest signal to your team that the business takes money seriously at every level.

The good news: petty cash is a solved problem. The imprest system, a fixed float, recorded spends, and periodic replenishment to receipts, has worked for over a century. You don’t need to invent anything. You just need to run the system properly.

Key Concepts

The imprest float. You set a fixed amount of petty cash, say, the equivalent of a fortnight’s minor expenses, and that’s the float. When it’s spent down, the custodian submits the receipts and gets reimbursed exactly that amount, restoring the float to its original level. At any moment, cash on hand plus receipts should equal the float. If it doesn’t, something is wrong, and you know immediately.

Custodianship. One named person holds the petty cash. Not the office generally, not whoever’s around, one person, whose name is on the record. They’re responsible for the float, they disburse it, they collect the receipts. Shared custody means shared blame, which means no accountability.

The receipt rule. No receipt, no reimbursement, with a narrow exception for genuinely receiptless spends (a market stall, a parking meter), which get a written note signed by the claimant. The rule must be universal: it applies to the owner too. The moment exceptions are made for seniority, the system is dead.

Segregation of duties. The custodian disburses and records. Someone else, a manager or the business owner, reviews and approves the replenishment. The person who holds the cash doesn’t approve their own paperwork.

Practical Steps

Step 1: Set the float and name the custodian. Choose a float that covers typical small expenses for two to four weeks, small enough that a loss wouldn’t hurt, large enough that you’re not replenishing weekly. Document the float amount, the custodian’s name, and the date it was issued. Both the custodian and the owner sign.

Step 2: Record every movement in the log. Every disbursement gets a line: date, recipient, purpose, amount, receipt reference. Every top-up gets a line too. The log is the single source of truth, if it’s not in the log, it didn’t happen.

Step 3: Enforce the receipt discipline. Every claim needs a receipt, attached to or referenced by the log entry. For the rare receiptless expense, the claimant writes what it was, when, and how much, and signs it. Set a small threshold, anything above it without a proper receipt doesn’t get reimbursed. Check your local regulations for what counts as acceptable evidence for tax purposes.

Step 4: Reconcile monthly, surprise occasionally. Every month, the custodian counts the cash, lists the receipts, and confirms the two add up to the float. A manager reviews and signs. On top of that, do an unannounced count once or twice a year. Surprise counts are the single most effective deterrent to petty cash misuse, and they take ten minutes.

Step 5: Replenish to receipts, never round up. When the float runs low, the custodian submits the receipts and receives exactly the amount spent, restoring the original float, no more. Never top up “to a round number” or add extra “just in case.” The float is fixed; that’s the point.

Step 6: Keep it separate from the till. Petty cash and sales takings must never mix. The float is a fixed amount issued for expenses; the till is revenue. Topping up petty cash from the day’s takings destroys the audit trail for both. If cash takings need banking, bank them; if petty cash needs replenishing, write a cheque or transfer for the receipted amount.

Common Mistakes

The float creeps. Someone tops up petty cash without receipts “because it was running low.” Someone else borrows from it for a personal expense “and pays it back tomorrow.” Each exception seems harmless. Each one breaks the fundamental equation, cash plus receipts equals float, and once it’s broken, the log is fiction.

IOUs instead of receipts. An IOU in the petty cash box is not a receipt. It’s a promise, and promises don’t reconcile. Either the expense happened (record it with evidence) or it didn’t (put the cash back). No IOUs, no exceptions.

The custodian is also the approver. When one person holds the cash, records the spends, and approves the replenishment, you have no control at all, just paperwork. The review step must be a different person, even in a tiny business. The owner can be the reviewer.

Reconciliation only at year end. An annual count tells you the float is wrong but not when it went wrong or why. Monthly reconciliation catches problems while the trail is fresh and the amounts are small.

No limit on what petty cash can buy. Petty cash is for small, incidental expenses. Without a policy limit per transaction, it gradually becomes the way to dodge the purchase approval process. Set a maximum per spend, anything above it goes through normal procurement with a purchase requisition.

Keeping it all in one person’s head. If only the custodian understands the system, it collapses when they’re on holiday. The rules should be written down, one page, so anyone can cover.

Relevant Templates

Petty Cash Log Sheet, the core record: every disbursement and top-up, receipt references, running balance against the float
Cash Reconciliation Sheet, the monthly count: cash on hand plus receipts verified against the float, with reviewer sign-off
Expense Claim Form, for staff spending their own money first; keeps out-of-pocket claims separate from the float
Purchase Requisition Form, the upstream control: anything above the petty cash limit goes through proper approval