---
title: "Arithmetic & comparison — Money for Laravel | Roundly"
description: "Same-currency arithmetic that rounds exactly once, cash rounding, exact comparisons and sum, min, max and average aggregates."
url: https://roundly-consulting.com/open-source/docs/money-for-laravel/arithmetic
language: en
---

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[Money for Laravel](https://roundly-consulting.com/open-source/docs/money-for-laravel.md)

# Arithmetic & comparison

Arithmetic and comparisons work within one currency — mixing currencies throws CurrencyMismatch, and conversion is always an explicit step. Lossless operations never round; lossy ones round exactly once, defaulting to RoundingMode::HalfAwayFromZero:

```php
$price = Money::ofMajor('19.99', 'EUR');
$fee   = Money::ofMinor(250, 'EUR');

$total = $price->add($fee)->multiply(3);   // 67.47 EUR, exact
$net   = $total->subtract($fee);           // 64.97 EUR
$vat   = $total->percentage('20');         // 13.49 EUR — one rounding, HalfAwayFromZero
$net->multiply('1.19');                    // 77.31 EUR — a decimal factor rounds once
$total->divide(4);                         // 16.87 EUR
Money::ofMajor('10.03', 'CHF')->roundTo(5); // 10.05 CHF — 5-Rappen cash rounding
$total->negate();                          // -67.47 EUR
$total->negate()->abs();                   // 67.47 EUR

$total->add(Money::ofMajor('1', 'USD'));   // throws CurrencyMismatch
```

- add() / subtract() — variadic, exact, never round.
- multiply($factor, $rounding) — an integer factor is exact; a decimal string ('1.19') or a Ratio rounds once.
- divide($divisor, $rounding) — rounds once; zero throws DivisionByZero.
- percentage($percent, $rounding) — this × p / 100, rounded once.
- roundTo($minorIncrement, $rounding) — cash rounding to a multiple of the increment, e.g. roundTo(5) for Swiss 5-Rappen steps.
- negate() / abs() — never round.

Factors and divisors must be plain decimals or integers — '1e3', '1,5' or ' 2' throw InvalidAmount. Results are capped at 65 digits.

## Comparison

```php
$a = Money::ofMajor('50', 'EUR');
$b = Money::ofMajor('67.47', 'EUR');

$b->isGreaterThan($a);                    // true
$b->isGreaterThanOrEqualTo($a);           // true
$a->isLessThan($b);                       // true
$a->isLessThanOrEqualTo($b);              // true
$a->compareTo($b);                        // -1
$a->equals(Money::ofMinor(5000, 'EUR'));  // true
$a->equals(Money::ofMajor('50', 'USD'));  // false — equals() never throws
$a->isSameCurrency($b);                   // true
$a->isZero(); $a->isPositive(); $a->isNegative();

$a->isGreaterThan(Money::ofMajor('1', 'USD')); // throws CurrencyMismatch
```

equals() compares the amount, the currency code and the exponent, and never throws. Every ordering method throws CurrencyMismatch across currencies. Comparisons run on the canonical strings — no bcmath, no float.

## Aggregates

```php
$prices = [
    Money::ofMajor('10', 'EUR'),
    Money::ofMajor('25.50', 'EUR'),
    Money::ofMajor('4.99', 'EUR'),
];

Money::sum($prices);                        // 40.49 EUR
Money::sum([], currencyIfEmpty: 'EUR');     // 0.00 EUR
Money::min($prices);                        // 4.99 EUR
Money::max($prices);                        // 25.50 EUR
Money::average($prices);                    // 13.50 EUR — rounded once
```

sum() of an empty list needs currencyIfEmpty, otherwise it throws EmptyMoneyCollection — as do min(), max() and average() of nothing. Non-Money items throw InvalidMoneyValue; mixed currencies throw CurrencyMismatch.

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