# Java: Remainder (modulo) operator with negative numbers

```
-11 % 5 == -1
11 % -5 == 1
-11 % -5 == -1
```

The sign of the first operand decides the sign of the result.

`x % y`

always equals `x % -y`

.

You can think of the sign of the second operand as being ignored.

Here’s a diagram of `x % 5`

(which is the same as `x % -5`

).

## Why?!

The `%`

computes the **remainder** in a division and should not be confused with the concept of modulo arithmetic.

According to the spec (§15.17.3), the following should always hold:

```
(a / b) * b + (a % b) == a
```

That is, `a % b`

should always represent the remainder of an integer division, and the remainder always has the same sign as the dividend.

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