What does $4.37 round to in cash?
$4.35. It ends in 7, and 1, 2, 6 and 7 round down. The digit is the whole rule.
Exact total
$4.37
Due in cash
$4.35
Rounded down by 2¢ — the total ends in 7.
$4.37 becomes $4.35 in cash — rounded down by 2¢ because the total ends in 7.
The order of operations
| Subtotal, exact | $4.37 |
| Tax at 0%, on the exact subtotal | $0.00 |
| Total, exact | $4.37 |
| Rounding — Symmetric (nearest nickel) | -2¢ |
| Due | $4.35 |
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Rounding applies to cash only
Card, electronic transfer, and gift-card payments are still priced to the cent. The same basket can therefore come to two different amounts depending on how it is paid for, and that is the intended behaviour rather than a bug — rounding exists because exact change is impossible without the penny, which is not a problem a card has.
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Round the final total, after tax — never per item
Line items, fees, and tax are each computed in exact cents first, and only the final amount is rounded. Rounding per item multiplies the effect by the size of the basket, and rounding the tax base makes the register disagree with the tax authority. Every state framework enacted so far applies rounding after tax is calculated.
Note
No tax rate was given, so none was applied
Rounding happens after tax, so the tax rate changes which nickel a basket lands on. A subtotal that rounds down at 0% can round up at 8.25%.
What to do: Pass taxRatePercent to see the total the customer actually pays.
Note
The penny is still money
Production ended on 2025-11-12, but existing pennies remain legal tender indefinitely. Production stopping is not demonetisation, and a customer paying in exact change with pennies is paying in valid currency.
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There is no federal rounding law yet
Common Cents Act (H.R.3074 / S.1525) passed the House on 2026-07-14 and the Senate on 2026-08-07, but as different bill numbers, so the House must still pass the Senate version before it can be enacted. Until then rounding is governed by state law, which varies — and the federal bill is permissive rather than mandatory anyway. Verified 2026-09-04; check for changes.
What to do: Check your own state law. This tool does not know where you are.
Run your own numbers
Use the form on the home page, or call the API or MCP server. This page is also available as markdown.
Related examples
Not legal, tax, or accounting advice. Federal rounding legislation was not enacted as of September 2026, state law varies and is changing quickly, and a rounding practice that is lawful in one state may not be in another. This computes arithmetic under a rule you select; it does not tell you which rule applies to your business. Check your own state law and your own tax authority.