To set up a petty cash fund, write a short policy that defines what the fund covers and caps how much can leave it at once, cut a company check to a designated custodian for the total amount, record the money as a Petty Cash asset on your books, and require a signed voucher and receipt for every disbursement. Most funds run between $100 and $500, and the whole setup takes about an hour. What determines whether the fund stays useful or becomes a slow leak is the controls you wrap around it from day one.
Decide How Much Cash the Fund Should Hold
Size the fund by estimating what you will spend on small incidentals between replenishment cycles. If the office typically runs through $40 a week on qualifying items and you plan to replenish monthly, $200 gives you comfortable headroom. A fund that hits empty every ten days pressures people to skip documentation. A fund that sits mostly untouched ties up cash for no reason.
Set a minimum balance that triggers replenishment, such as 25 percent of the starting amount, so the box never bottoms out unexpectedly. Review the balance every six months and adjust up or down based on actual spending.
Write the Policy Before Any Cash Moves
A short internal policy answers four questions: what expenses qualify, how much any single transaction can be, how large the fund will be, and how often you will replenish it. Being specific up front prevents the fund from turning into an informal lending drawer.
Set a per-transaction cap. Most businesses land between $25 and $75. Anything above the cap should flow through your normal purchasing process, where you get better documentation and approval. List the categories the fund covers, such as postage, courier charges, emergency parking, or small cleaning supplies. Then list what the fund is not for. Meals, personal advances, and gift cards are common exclusions, and putting them in writing saves arguments later.
Fund the Account and Record the Entry
Open the fund by writing a company check payable to your designated custodian for the full amount. In your general ledger, debit the Petty Cash asset account and credit your main Cash account. That entry moves the money from the bank into a separate asset line, where it stays at the same balance until you deliberately increase, decrease, or close the fund.
This starting balance is the imprest amount. It does not move when people spend from the box, and it does not move when you replenish. It only changes if you decide the fund itself should be a different size.
Pick a Custodian and Lock Up the Cash
The custodian is the single person responsible for the physical cash and every piece of paperwork attached to it. Choose someone whose regular duties do not include approving purchases or reconciling bank statements. Someone who can both spend from the fund and hide the spending in the books is someone your controls cannot catch.
Have the custodian sign a written acknowledgment of the policy, including the per-transaction cap and the eligible expense categories. Store the cash in a dedicated box or small safe that only the custodian can access. A fireproof container rated for paper documents is worth the modest investment, since both the currency and the receipts inside need to survive an office incident. Keep the box out of sight of visitors and out of reach of general staff.
How Disbursements Work
Every withdrawal starts with a petty cash voucher, filled out before or at the moment cash leaves the box. A voucher captures four things: the date, the dollar amount, a short description of the business purpose, and the expense account that will be charged when you replenish. The person receiving the cash signs the voucher. The custodian, or a separate approver, signs to authorize it. That second signature is your verification that the expense fits the policy.
A third-party receipt has to accompany the voucher. The receipt proves the money was actually spent on what the voucher describes. Staple the receipt to the voucher and drop both into the box in place of the disbursed currency.
At any moment, the box should contain a combination of cash and documented vouchers that adds up to the original fund balance. Count the contents at any time and the total should match. That is the core of the imprest system, and it makes discrepancies visible right away instead of letting them accumulate.
Before handing over cash, the custodian checks the request against the policy. Does it fit an approved category? Is the amount under the per-transaction limit? Is there a clear business reason? If any answer is no, the request goes through normal purchasing. Custodians who get pressured into bending the rules on “just this one” are custodians whose funds will not reconcile.
Keep Reimbursements Off the Employee’s W-2
Petty cash reimbursements are not automatically tax-free. For employee reimbursements to stay off payroll, your process has to qualify as an accountable plan under federal tax rules. An accountable plan has three requirements: the expense must have a business connection, the employee must substantiate it with adequate documentation, and the employee must return any advance that exceeds what was actually spent.
The IRS treats expenses substantiated within 60 days of being paid or incurred as meeting the reasonable-period standard, and excess amounts returned within 120 days as timely. If the process fails any of these requirements, the reimbursements become a nonaccountable plan, which means every dollar disbursed gets included in the employee’s gross income, reported on their W-2, and subjected to income tax withholding and employment taxes.1Internal Revenue Service. Revenue Ruling 2003-106
A well-run petty cash system with signed vouchers, receipts, and timely replenishment will satisfy these rules without extra effort. The danger is a sloppy system where employees pocket advances without turning in receipts, or where months pass before anyone reconciles the box.
Reconcile Before You Replenish
Reconciliation comes first, every time. The custodian counts the remaining cash, totals all vouchers and their attached receipts, and adds the two numbers. That sum should equal the original fund balance exactly. If the fund started at $200 and you have $47 in cash plus $153 in documented vouchers, you are whole.
When the numbers do not match, record the difference in a Cash Short and Over account on the income statement. A shortage shows up as a miscellaneous expense. An overage shows up as miscellaneous income. The amounts are typically small. Persistent shortages in one direction, though, are a signal that something in the process is breaking down, and you should investigate before replenishing.
Once the totals are confirmed, prepare a replenishment request for the exact amount of the accumulated vouchers, adjusted for any shortage or overage. The journal entry debits each expense account identified on the vouchers (office supplies, postage, parking, and so on) and credits the main Cash account for the total. The Petty Cash asset account is not touched. It stays at the original imprest balance because you are simply refilling the box to its starting level. The custodian cashes the replenishment check, puts the currency back in the box, and the cycle starts again.
Build in Basic Controls From the Start
The single most effective control is separation of duties. The custodian handles the cash and prepares the vouchers. A different person approves the replenishment check. A third person, ideally in accounting or management, reviews the vouchers and reconciliation before the check is cut. No one person should be able to take cash, create the paperwork justifying it, and approve the replacement funds without anyone else touching the process.
Surprise counts matter almost as much. Have someone other than the custodian open the box unannounced, count the cash, total the vouchers, and compare the result to the imprest balance. Once a quarter, at unpredictable intervals, is enough to keep the system honest without being burdensome. The point is not that you expect theft. It is that everyone involved knows the box could be opened and counted at any time.
Watch for patterns that suggest the system is being gamed. Vouchers with round-dollar amounts and no receipts. A spike in disbursements right before a scheduled reconciliation. Repeated expenses to the same vendor with no clear business need. Transactions split into smaller amounts to stay under the per-transaction cap, sometimes called structuring, which is one of the easiest abuses to spot and one of the hardest to justify.
Keep every voucher, receipt, and reconciliation summary. The IRS requires you to maintain records for as long as they support the income or deductions on a return, and the standard examination window is three years from the filing date.2Internal Revenue Service. Recordkeeping