# round

Round to nearest decimal or integer

## Syntax

• `Y = round(X)` example
• `Y = round(X,N)` example
• `Y = round(X,N,type)` example
• `Y = round(t)` example
• `Y = round(t,unit)` example

## Description

example

````Y = round(X)` rounds each element of `X` to the nearest integer. In the case of a tie, where an element has a fractional part of exactly `0.5`, the `round` function rounds away from zero to the integer with larger magnitude.```

example

````Y = round(X,N)` rounds to `N` digits:`N > 0`: round to `N` digits to the right of the decimal point.`N = 0`: round to the nearest integer.`N < 0`: round to `N` digits to the left of the decimal point.```

example

````Y = round(X,N,type)` specifies the type of rounding. Specify `'significant'` to round to `N` significant digits (counted from the leftmost digit). In this case, `N` must be a positive integer.```

example

````Y = round(t)` rounds each element of the `duration` array `t` to the nearest number of seconds.```

example

````Y = round(t,unit)` rounds each element of `t` to the nearest number of the specified unit of time.```

## Examples

collapse all

### Round Matrix Elements

Round the elements of a 2-by-2 matrix to the nearest integer.

```X = [2.11 3.5; -3.5 0.78]; Y = round(X)```
```Y = 2 4 -4 1```

### Round to Specified Number of Decimal Digits

Round `pi` to the nearest 3 decimal digits.

`Y = round(pi,3)`
```Y = 3.1420```

### Round to Nearest Multiple of 100

Round the number `863178137` to the nearest multiple of 100.

`round(863178137,-2)`
```ans = 863178100```

### Round Elements to Specified Number of Significant Digits

Round the elements of a vector to retain 2 significant digits.

```format shortg x = [1253 1.345 120.44] y = round(x,2,'significant')```
```x = 1253 1.345 120.44 y = 1300 1.3 120```

### Controlling Number Display While Rounding

The `format` command controls how MATLAB® displays numbers at the command line. If a number has extra digits that cannot be displayed in the current format, then MATLAB automatically rounds the number for display purposes. This can lead to unexpected results when combined with the `round` function.

Consider the result of the following subtraction operation, which displays 5 digits.

```format short x = 112.05 - 110```
```x = 2.0500```

Based on the displayed value of `x`, rounding `x` to 1 decimal should return `2.1`.

`round(x,1)`
```ans = 2```

In fact, the problem here is that MATLAB is rounding `x` to 5 digits for display purposes. The `round` function returns the correct answer. Confirm the answer by viewing `x` with ```format long```, which displays `x` rounded to 15 digits.

```format long x```
```x = 2.049999999999997```

### Round Duration Values

Round each value in a duration array to the nearest number of seconds.

```t = hours(8) + minutes(29:31) + seconds(1.3:0.5:2.3); t.Format = 'hh:mm:ss.SS' ```
```t = 08:29:01.30 08:30:01.80 08:31:02.30 ```
```Y1 = round(t) ```
```Y1 = 08:29:01.00 08:30:02.00 08:31:02.00 ```

Round each value in t to the nearest number of hours.

```Y2 = round(t,'hours') ```
```Y2 = 08:00:00.00 09:00:00.00 09:00:00.00 ```

## Input Arguments

collapse all

### `X` — Input arrayscalar | vector | matrix | multidimensional array

Input array, specified as a scalar, vector, matrix, or multidimensional array. For complex `X`, `round` treats the real and imaginary parts independently.

`X` must be `single` or `double` when you use `round` with more than one input.

`round` converts logical and `char` elements of `X` into `double` values.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64` | `char` | `logical`
Complex Number Support: Yes

### `N` — Number of digitsscalar integer

Number of digits, specified as a scalar integer. When you specify `N`, the `round` function rounds `X` to the nearest multiple of 10 -N.

If you specify the `'significant'` rounding type, then `N` must be a positive integer.

### `type` — Rounding type`'decimals'` (default) | `'significant'`

Rounding type, specified as `'decimals'` or `'significant'`. The rounding type determines whether `round` considers digits in relation to the decimal point or the overall number of significant digits. `N` must be a positive integer when you specify `'significant'`. In that case, the `round` function rounds to the nearest number with `N` significant digits.

The default value is `'decimals'`, so that `round(X,N,'decimals')` is equivalent to `round(X,N)`.

Example: `round(3132,2,'significant')` returns `3100`, which is the closest number to `3132` that has `2` significant digits.

Data Types: `char`

### `t` — Input duration`duration` array

Input duration, specified as a `duration` array.

### `unit` — Unit of time`'seconds'` (default) | `'minutes'` | `'hours'` | `'days'`

Unit of time, specified as `'seconds'`, `'minutes'`, `'hours'`, or `'days'`.

collapse all

### Compatibility Considerations

In R2014b, these syntaxes were added to round to any number of decimal or significant digits and to round duration values:

```Y = round(X,N) Y = round(X,N,type) Y = round(t) Y = round(t,unit) ```

Older versions support only this syntax, which rounds to the nearest integer:

`Y = round(X) `

### Tips

• `format short` and ```format long``` both display rounded numbers. This can cause unexpected results when combined with the `round` function.

• For display purposes, use `sprintf` to control the exact display of a number as a string. For example, to display exactly 2 decimal digits of `pi` (and no trailing zeros), use `sprintf('%.2f',pi)`.