The imprest system in plain English.
Imprest means "fixed advance." A petty cash custodian receives a fixed amount, say $50,000, at the start of the cycle. He pays small expenses from it, collecting a receipt for each. When the float is depleted, he submits all receipts plus remaining cash to head office. The total should equal $50,000 (cash + receipts). Head office reimburses the spent amount, restoring the float to $50,000. The cycle repeats.
The genius of imprest is that it forces reconciliation every cycle. The custodian cannot accumulate quietly because the float never grows. Receipts are submitted while still fresh in memory. Head office accountants book all expenses to the right accounts at replenishment time, not weeks or months later. Compared to a "rolling" petty cash where the custodian gets ad-hoc top-ups, imprest is dramatically easier to control.
Setting the right float size.
Float size should cover roughly two to four weeks of typical petty cash spend. Too small and you replenish weekly, generating overhead. Too large and the custodian holds excess cash, which is theft risk and idle capital. For a single-branch SMB with 30-50 small transactions a week, $25,000-50,000 float is typical. For a multi-branch business, each branch holds a separate float sized to its own activity.
Set the float by observation, not gut. Track petty cash spend for two months on the looser system, calculate weekly average, and set float at 2-4 weeks of average. Revisit annually because spend patterns change. A branch that opens earlier or expands service hours will outgrow its old float quickly.
Receipt discipline, the non-negotiables.
Every petty cash spend gets a receipt. No receipt, no reimbursement to the custodian. The receipt must show vendor name, date, amount, and what was bought. For purchases below $500 where the vendor truly cannot give a receipt (street tea vendor, parking attendant), the custodian writes a voucher with the same fields and the manager signs.
Within Nonari, the petty cash module accepts photo receipts: snap on phone, attach to the entry. OCR pulls vendor and amount. The accountant reviews and books to the right expense account. Lost receipts disappear because the photo is stored centrally, not as paper that can be misplaced. Branches with this discipline have 100% receipt coverage; branches without average around 60-70%, which means 30-40% of spend has no audit trail.
Replenishment, the right way.
When the float is depleted (commonly 80% used as the trigger), the custodian gathers all receipts, totals them, and submits a replenishment request. The accountant checks each receipt against expense categories: $1,500 office supplies, $3,200 staff tea and snacks, $850 courier, $12,000 vehicle fuel, etc. He posts a journal entry: DR Office Supplies 1,500 / DR Staff Welfare 3,200 / DR Postage 850 / DR Vehicle Fuel 12,000 / etc. / CR Petty Cash. The total credit equals the total reimbursement.
Then a separate cash transfer entry: DR Petty Cash / CR Bank. The float is restored to its starting amount. The custodian counts the float in front of the manager, signs, and the cycle restarts. Time per replenishment with disciplined documentation: 15-30 minutes. Time without: hours of investigation and missing receipts.
Common abuses and how to catch them.
Petty cash is the most-abused account in any SMB. Common patterns: receipts inflated ($350 actual, $850 written), fake receipts (purchased blank receipt books from print shops), personal expenses run through petty cash, the same receipt submitted twice across cycles. Detection methods: surprise float counts (cash + receipts must equal float), spot-check vendor calls (does this vendor exist at this address?), benchmarking spend per category against industry norms.
A monthly trend of "Staff Welfare" spend that grew from $8,000 to $28,000 over six months without any team growth is a flag. A branch where 90% of receipts come from the same five vendors is a flag. A custodian who never takes a day off (so the books are never opened by someone else) is a flag. None of these are proof, but they are signals worth investigating.
- Surprise count: cash + receipts = float, always.
- Verify vendors at the addresses on receipts.
- Trend-watch each expense category month over month.
- Rotate or cross-cover custodians at least annually.
- Compare per-branch spend ratios against revenue.
When petty cash is the wrong tool.
Petty cash should be small and frequent. If you find yourself paying suppliers $30,000 from petty cash, you are using the wrong instrument. Supplier payments should go through bank transfer or business credit card, both of which produce a clean digital audit trail. withholding tax may be triggered on supplier payments, which petty cash makes hard to track. Salaries should never be petty cash. Capital expenditures should never be petty cash.
Threshold rule: if a single transaction is over $5,000 (or 10% of float, whichever is lower), it should bypass petty cash and go through bank or card. This keeps petty cash for what it was meant for: tea, stationery, courier, parking, small repairs. Large transactions bring proper documentation needs that petty cash cannot satisfy.
Tax treatment of petty cash spend.
Petty cash expenses are deductible if they are wholly and exclusively for business under Section 20 of the your country’s tax code. Personal expenses run through petty cash are not deductible and, if discovered in audit, are added back to taxable income with potential penalty. The receipt is the proof; without it, your tax authority can disallow the deduction.
For sales tax, input tax on petty cash purchases is generally not claimable because the seller is usually unregistered (a tea shop, a parking attendant). Where the petty cash purchase is from a registered seller and qualifies under Section 7 (e.g., office supplies from a registered stationer), input tax can be claimed if you have a tax invoice. Without a tax invoice, no claim. Most SMBs forfeit this small input tax because the documentation hassle exceeds the recovery.
Going digital without going crazy.
A digital petty cash workflow on Nonari: custodian scans every receipt on phone within an hour of spending. The system OCRs vendor and amount, custodian categorizes (or accepts the AI suggestion). At replenishment, all entries for the cycle are visible in one screen. Accountant approves, posts the journal entry, and authorizes the bank transfer. No paper, no excel, no missing receipts.
The behavior change required: phone-snap habit. Most owners overestimate this hurdle. Once a custodian has seen one painful month-end of paper chasing, the snap habit sticks. Branches on digital petty cash close their float in 10 minutes. Branches still on paper close in 90 minutes with disputes. The ROI is real and immediate.