In this article
Since 1 December 2019, Belgian law has required it: a cash total rounds to the nearest 5 cents, never up. It's a rule almost every restaurant applies without ever having actually looked it up — and without knowing what a till that's configured just slightly differently collects every year.
1- and 2-cent coins cost more to mint than they're worth, and Europe is phasing them out one country at a time. Sweden did it back in 1972, Finland has rounded since euro cash launched in 2002, the Netherlands since 2004, Ireland via a voluntary convention since 2015, and Belgium by law since 1 December 2019. What's left behind is a rounding rule almost every till applies, and almost nobody can explain the moment someone actually asks.
That's not a small detail. A venue paid in cash forty times a day applies that rule forty times a day — and whether it's applied by the book or 'just round up, it's simpler' decides whether a few hundred euros a year show up that never appear as a line item on any invoice.
This article works through the rule with the actual math behind it — not an estimate, but the exact arithmetic that explains why rounding fairly costs a venue precisely nothing on average, what a till that always rounds up collects instead, and why the two get confused constantly in practice.
The calculator further down — alongside the free daily cash-up sheet — shows how a rounding error actually shows up in a real till: not as a shortage, which is what most till discrepancies are, but as an overage that almost nobody recognises as rounding.
Why a rounded cent is more than a rounded cent
A price on the menu is exact to the cent, and so is a card payment — neither of those changes. Only the amount paid in notes and coins gets rounded, and only because there are simply no 1- and 2-cent coins left in the drawer to hand back the exact difference.
That distinction — card stays exact, cash rounds — is the first place this goes wrong. A till that accidentally rounds card payments too, or that applies the rounding item by item instead of on the final total, has drifted from the rule as every country intends it: one rounding, on the total, cash only.
The seven numbers below take apart exactly what that one rounding, applied over and over, does to a venue — from the formula itself to the number that explains why an overage in the till is more often a rounding error than a generous guest.
The 7 numbers behind the rounding rule
Each of these seven numbers is its own calculation — together they explain why this rule exists, what it can cost a venue when it's set up just slightly differently, and how that translates to a real till.
1. The rule: to the nearest 5 cents, never further
The rule itself is simpler than it sounds. Look at the last digit of the cent amount above the previous multiple of 5: if a bill ends 0, 1 or 2 cents above it, the total rounds down; if it ends 3 or 4 cents above it, the total rounds up. A bill of €47.23 rounds to €47.25 (up, because it's 3 cents above €47.20). A bill of €47.21 rounds to €47.20 (down, because it's only 1 cent above).
That's the whole rule. No special case, no exception for large amounts — only the last two digits of the cent amount decide the direction, and the graphic below shows how that plays out for every possible last digit.
The cent amount above the previous multiple of 5 decides the direction — the same pattern repeats every 5 cents.
0, 1 and 2 round down; 3 and 4 round up. Add the five outcomes together (number 4 below) and the result is exactly zero.
2. Cash only — the number that causes the most confusion
The rule applies to exactly one thing: the total paid in notes and coins. The menu stays priced to the cent, a card or app payment settles to the cent, and even the receipt itself usually shows the exact, unrounded total right next to the amount actually collected in cash.
How much that matters in practice depends on how much cash is still used. The European Central Bank's most recent euro-area-wide payment-habits study (SPACE, 2022) found cash was still the most-used payment method at the till by NUMBER of transactions, even as that share keeps falling and already trails card by VALUE. For an average venue, that means the rounding rule doesn't touch every transaction — but it touches enough of them to make the next five numbers worth knowing.
3. 5 countries, 5 moments — and 1 still to come
The rounding rule isn't a Belgian invention. Sweden introduced it back in 1972, long before the euro existed. Finland has rounded since the first euro cents entered circulation in 2002 — the country never let large numbers of 1- and 2-cent coins circulate in the first place. The Netherlands followed in 2004, informal but applied almost everywhere. Ireland opted for a voluntary 'National Rounding Convention' in 2015, letting every retailer choose to opt in. Belgium made it mandatory by royal decree, effective 1 December 2019.
The rest of the EU doesn't round yet — France, Germany, Spain and most other member states still calculate to the cent, though a 2024 European Commission proposal to phase out 1- and 2-cent coin production EU-wide is on the table. What's a Belgian-Dutch-Scandinavian story today is, step by step, becoming a European one.
Five countries adopted the rule at different moments and in different ways — and the EU is weighing a shared framework.
Voluntary or mandatory, informal or by royal decree — the direction is the same everywhere: less small change in circulation, more rounding at the till.
4. 0 — the expected result of rounding fairly
This is the math that justifies the rule. Of the five possible last digits of a cent amount (0, 1, 2, 3 or 4 above the previous multiple of 5), the rule rounds down three times — by 0, -1 or -2 cents — and up twice — by +2 or +1 cents. Add those five outcomes together (0, -1, -2, +2, +1) and the result is exactly zero.
That's not a coincidence, it's the reason the rule is built this way: over enough transactions, rounding fairly costs a venue precisely nothing on average. Not 'roughly nothing' — mathematically guaranteed zero, as long as every last digit occurs equally often. That's also the benchmark every deviation below gets measured against.
5. 2 cents on average — what a till that always rounds up collects
Say a till doesn't round to the nearest 5 cents, but always rounds up — a small, easy-to-miss setting, or just the habit of never being short of change. The same five last digits then produce different outcomes: 0, +4, +3, +2 and +1 cents. Their average is €0.02 per transaction — small, but not zero, and not by accident: it's exactly the difference between rounding fairly and rounding systematically in the till's favour.
Run that through for a venue with 40 cash transactions a day over 300 service days a year, and €0.02 per transaction becomes €240 a year — money that never shows up as its own line on any invoice, because it hides inside hundreds of individual roundings of a few cents each.
What does rounding actually do to your till?
Enter a bill, your daily cash transaction count and a table size, and see the difference between rounding fairly and always rounding up.
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An illustrative model based on this page's own currency's smallest denomination — not a substitute for your own till system's settings.
The calculator above works in this page's own currency and its equivalent smallest denomination — 5 cents for the euro, the comparable smallest step for another currency. The principle doesn't change, only the step does.
What the calculator can't do is tell you which setting your own till is actually using today — which is exactly why number 7 above is worth checking before the next shift starts.
6. The split-bill trap
A table of 6 settling separately in cash surfaces a second problem. Round the bill's total once, and the deviation from the exact amount is bounded at half the rounding step at most — €0.03 in either direction, regardless of how many guests are at the table.
Round each of the 6 individual shares separately instead, and that bound grows to €0.15 in the worst case — 6 times as much as rounding the total once, because each separate rounding can happen to fall the same way. The difference isn't in the average — that stays zero per number 4 — it's in how far a single evening can drift from that average.
7. Why this explains an 'over', not a 'short'
Till discrepancies almost always get investigated in one direction: a shortage, usually caused by internal theft or a change-giving mistake. A structural rounding error runs the opposite way — it produces an overage, because a misconfigured till almost never asks for too little, only ever too much.
That makes the rounding rule the rare explanation for a till that counts slightly too much at the end of a shift instead of too little. Anyone who recognises that pattern in their own daily cash-up sheet — a small, recurring overage, never a shortage — should check the till's rounding setting first, before looking anywhere else.
Checking your own till: the plan
There's no complicated project here — just one setting to check and one habit to confirm.
Today
- Use the calculator above to check what your own till does with a bill ending in 3 or 8 cents — does it round to the nearest 5 cents, or always up?
- Ask your till system's supplier exactly how the rounding setting is configured — most systems offer both options.
This week
- Check the last two weeks of daily cash-up sheets for a small, recurring cash overage — exactly the pattern a misconfigured rounding setting leaves behind.
- Explain to staff that rounding isn't 'up is safer' — it's a fixed rule with a fixed direction.
Ongoing
- Add the rounding setting to the opening round of the checklist after every till software update — an update sometimes resets configuration to its default.
- Revisit the setting whenever your country updates its own rounding legislation — the map in number 3 above is still changing, the way it already has five times in the last fifty years.
The number that counts
Rounding to the nearest 5 cents isn't a trap — it's a tidy solution to a practical problem, since there are no 1- and 2-cent coins left to hand back exact change, and applied as intended, it changes nothing, mathematically, about what a venue keeps.
It's only when the rule is set up just slightly differently — always up instead of to the nearest 5 cents — that the difference becomes visible: small per transaction, but recognisable in the annual total and in the kind of till discrepancy it leaves behind.
Check today with the calculator above which setting your own till is actually using, and check the next daily cash-up sheet for the pattern from number 7 — a small, recurring overage that's never a shortage.