PHP gives incorrect results when formatting long numbers

Question

I am working with huge numbers for website purposes and I need long calculation. When I echo a long number I don't get the correct output.

Example

// A random number
$x = 100000000000000000000000000;

$x = number_format($x);
echo "The number is: $x <br>";
// Result: 100,000,000,000,000,004,764,729,344 
// I'm not getting the value assigned to $x

Its because its way far greater than the `PHP_INT_MAX` value. The exact numbers are `2147483647 (32-bit)` and `9223372036854775807 (64-bit)`. http://php.net/manual/en/language.types.integer.php — Narendrasingh Sisodia, Feb 03 '16 at 06:31
This might help you http://stackoverflow.com/questions/19023840/purpose-of-the-max-number-in-php-mysql — Afsar, Feb 03 '16 at 06:32
yes i am aware of int bigint and of course decimals but is there any solution ? — deerox, Feb 03 '16 at 06:33

maxhb · Accepted Answer · 2016-02-03T07:13:07.553

9

Your number is actually too big for php standard integers. php uses 64 bit integers which can hold values within range -9223372036854775808 (PHP_INT_MIN) to +9223372036854775807 (PHP_INT_MAX).

Your number is about 87 bits long which simply is too much.

If you really need such big numbers you should use the php BC math types, explained in the manual: http://php.net/manual/en/ref.bc.php

If you just want to format a string formed like a huge number then use something like this:

function number_format_string($number) {
    return strrev(implode(',', str_split(strrev($number), 3)));
}

$x = '100000000000000000000000000';

$x = number_format_string($x);
echo "The number is: $x\n";

// Output: The number is: 100,000,000,000,000,000,000,000,000

Edit: Added strrev() to function because the string needs to be reversed before splitting it up (thanks to @ceeee for the hint). This ensures that the delimiter is placed at right position when length of input is not divisible by 3. Generated string needs to be reversed afterwards again.

Working example can be found at http://sandbox.onlinephpfunctions.com/code/c10fc9b9e2c65a27710fb6be3a0202ad492e3e9a

edited Feb 03 '16 at 07:13

answered Feb 03 '16 at 06:35

maxhb

7,819
9
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yes is there something i can do like converting it to decimal ? – deerox Feb 03 '16 at 06:36
Added example on how to format an integer number contained in a string. – maxhb Feb 03 '16 at 06:40
thanks let me try with my more bigger nubmers once :) – deerox Feb 03 '16 at 06:42
that worked need to make my own function for more longer numbers but thanks alot it got me an idea :) – deerox Feb 03 '16 at 06:50
Its really a great example as you don't need to use `BC match` type of PHP +1 – Narendrasingh Sisodia Feb 03 '16 at 06:59
removed my +1 due to bug – Ceeee Feb 03 '16 at 07:02
Thanks for the comment, found the problem and solved it in my last edit. – maxhb Feb 03 '16 at 07:14

Ceeee · Answer 2 · 2016-02-03T07:26:01.577

6

answer @maxhb has bug. if the input is '10000000000000000000000' the out put would be:

The number is: 100,000,000,000,000,000,000,00

Which is incorrect. So try below code:

function number_format_string($number, $delimeter = ',')
{
    return strrev(implode($delimeter, str_split(strrev($number), 3)));
}

$x = '10000000000000000000000';

$x = number_format_string($x);
echo "The number is: $x\n";

// Output: The number is: 10,000,000,000,000,000,000,000

edited Feb 03 '16 at 07:26

answered Feb 03 '16 at 07:01

Ceeee

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My solutions does not output what you stated, it outputs what I wrote, see http://sandbox.onlinephpfunctions.com/code/934d67b6986af5e68dcac9a646486061c3d6b794 – maxhb Feb 03 '16 at 07:05
@maxhb Hi Sir, Try 10000000000000000000000 – Ceeee Feb 03 '16 at 07:08
thats working fine unless we give `$x = 100000000000000000000000000;` – deerox Feb 03 '16 at 07:08
or try $x = 1000. Output would be The number is: 100,0 – Ceeee Feb 03 '16 at 07:10

score 2 · Answer 3 · answered Feb 03 '16 at 06:42

The largest integer that can be represented in a 64bit PHP install, compared to your number:

   9,223,372,036,854,775,808 - largest possible signed 64bit integer
   100000000000000000000000000 - your number

since you're exceeding the maximum number size, you can't expect to get useful results without using something like gmp/bcmath.

score 0 · Answer 4 · answered Dec 04 '20 at 11:50

PHP does not yet support formatting long numbers, even when you always keep them as strings in your code (to avoid issues with PHP’s int type):

php > echo number_format('100000000000000000000000000');
100,000,000,000,000,004,764,729,344
php > echo number_format('3.14159265358979323846', 20);
3.14159265358979311600

The underlying ICU library supports formatting arbitrary precision decimal numbers, but PHP doesn’t use the relevant function yet – see request #76093.

score -1 · Answer 5 · answered Feb 03 '16 at 06:51

http://php.net/manual/en/function.number-format.php

That is the solution:

<?php

#    Output easy-to-read numbers
#    by james at bandit.co.nz
function bd_nice_number($n) {
    // first strip any formatting;
    $n = (0+str_replace(",","",$n));
    // is this a number?
    if(!is_numeric($n)) return false;
    // now filter it;
    if($n>1000000000000) return round(($n/1000000000000),1).' trillion';
    else if($n>1000000000) return round(($n/1000000000),1).' billion';
    else if($n>1000000) return round(($n/1000000),1).' million';
    else if($n>1000) return round(($n/1000),1).' thousand';

    return number_format($n);
    }
?>

No i am not looking for converting my long number to short with billions or trillions — deerox, Feb 03 '16 at 06:52

PHP gives incorrect results when formatting long numbers

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