Round Up to Nearest Multiple of Five in PHP

Round up to nearest multiple of five in PHP

This can be accomplished in a number of ways, depending on your preferred rounding convention:

1. Round to the next multiple of 5, exclude the current number

Behaviour: 50 outputs 55, 52 outputs 55

function roundUpToAny($n,$x=5) {
    return round(($n+$x/2)/$x)*$x;
}

2. Round to the nearest multiple of 5, include the current number

Behaviour: 50 outputs 50, 52 outputs 55, 50.25 outputs 50

function roundUpToAny($n,$x=5) {
    return (round($n)%$x === 0) ? round($n) : round(($n+$x/2)/$x)*$x;
}

3. Round up to an integer, then to the nearest multiple of 5

Behaviour: 50 outputs 50, 52 outputs 55, 50.25 outputs 55

function roundUpToAny($n,$x=5) {
    return (ceil($n)%$x === 0) ? ceil($n) : round(($n+$x/2)/$x)*$x;
}

Round integer to nearest multiple of 5 in PHP

Use round() instead of ceil().

5 * round($n / 5);

ceil() rounds a floating point number up to its next integer in sequence. round() will round to the nearest integer using standard rounding rules.

round to nearest multiple of 5 in a range in php

Let say $x has the number:

$x = 39;

If you want the closest multiple of 5 (39 --> 40):

$x = round($x / 5) * 5;

If you want to round up (36 --> 40):

$x = ceil($x / 5) * 5;

If you want to round down (39 --> 35):

$x = floor($x / 5) * 5;

After defining $x, you can use the following to make sure its in the 25-45 range:

$x = ($x > 45) ? 45 : ($x < 25) ? 25 : $x;

Round to nearest 5 or 9 in PHP

This is a bit, non mathy but should work:

function round9($n) {
    $n = ceil($n);
    $r = substr($n,-1) > 5 ? 9 : 5;
    $n = substr($n,0,-1) . $r;
    return $n;
}

• first round up to nearest integer
• get last digit
• replace last digit with 9 if it's greater than 5. otherwise replace with a 5.

UPDATE: I thought this was an interesting problem and now that we've got three correct answers which solve it from very different angles I thought I'd do a bit of performance analysis for my own curiosity. neuro_sys's answer wins by far! Here are the results in seconds to complete 10 million iterations:

time to build array: 1.7170281410217
round9: 10.753921985626
my_round: 1.6339750289917
rounder: 16.578145980835

Test was run on an 8GB, 4 Core Linode VPS running Ubuntu 16.04 / PHP 7.0.14

How can I round down to the nearest multiple of 3 in PHP?

Is this what you looking for.

/**
 * Round an integer down to the nearest multiple of the given multiple
 * @param integer $number
 * @param integer $multiple
 * @return integer
 */
 function round_down_to_multiple_of( int $number, int $multiple = 3 ): int
 {
    return (int)($multiple * floor( $number/$multiple ));
 }

 # TESTS
 $numbers = [ 10, 9, 8, 1, 0 ];
foreach( $numbers as $number ){
    printf( '%d became %d'.PHP_EOL, $number, round_down_to_multiple_of( $number, 3 ) );
}

After running the above test I get the following results:

10 became 9
9 became 9
8 became 6
1 became 0
0 became 0

PHP Round to previous multiple of 5 decimal

an easy solution, floor the double number and divide by two... 2 cents ;)

<?php

function roundToPreviousMultipleWithDecimal(float $number){

        return $specificRound = floor($number * 2) / 2;
}

$a = 8.4;
$b = 8.6;
$c = 8.9;
$d = 9.0;

echo roundToPreviousMultipleWithDecimal($a) ."<br />";
echo roundToPreviousMultipleWithDecimal($b) ."<br />";
echo roundToPreviousMultipleWithDecimal($c) ."<br />";
echo roundToPreviousMultipleWithDecimal($d) ."<br />";

How can I round up from number 621 to 700 in PHP?

I think you are trying to round off a number to the nearest 100.
Simply do this by using the ceil function.

ceil(621 / 100) * 100;

You can use ceil function to round any number to its nearest number.

$number = ceil($inputNumber / $nearestNumber) * $nearestNumber;

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