How to Format a Number to a Dollar Amount in PHP

This tutorial article will cover different methods to format a number to a dollar amount in PHP with examples. These include:

• number_format
• NumberFormatter::formatCurrency
• Regular expressions
• Manual format

We will also look at why the money_format function is no longer used.

Format a Number to a Dollar Amount in PHP Using the number_format Function

We use the number_format function to arrange a value with grouped thousands while adding decimal places and a currency type.

The function has four parameters:

number_format(NUMBER, DECIMAL DIGITS, THOUSANDS SEPARATOR, DECIMAL SEPARATOR)

• The number is the value to be formatted.
• Decimal digits specify how many decimal places.
• Decimal separator identifies what string to use for the decimal point.
• Thousand separator dictates the string used as a thousands separator.

It is worth noting if the thousand separator parameter is in use, the other three must accompany it for your code to work.

Example code:

<?php

//  NUMBER
$amount = 123.45;

//  TO USD - $123.45
$usd = "$" . number_format($amount, 2, ".");
echo $usd;
?>

Output:

$123.45

Format a Number to a Dollar Amount in PHP Using the NumberFormatter::formatCurrency Function

This is the latest and arguably the easiest method to format numbers to strings showing different currencies.

Ensure the extension=intl is enabled in php.ini.

There are three parameters you should keep in mind:

• Formatter, which is the NumberFormatter object.
• Amount, which is the numeric currency value.
• The ISO 4217 dictates the currency to use.

Example code:

<?php
// NUMBER
$amount = 123;

// TO USD - $123.00
$fmt = new NumberFormatter("en_US",  NumberFormatter::CURRENCY);
$usd = $fmt->formatCurrency($amount, "USD");
echo $usd;
?>

Output:

$123.00

Example two:

<?php
// NUMBER
$amount = 123.456;

// TO USD - $123.46
$fmt = new NumberFormatter("en_US",  NumberFormatter::CURRENCY);
$usd = $fmt->formatCurrency($amount, "USD");
echo $usd;
?>

Output:

$123.46

Format a Number to a Dollar Amount in PHP Using a Regular Expression

This method is a whole can of worms. Going into its details will only confuse you.

This method arranges numbers into thousands while adding the currency sign of your choice.

Let us take a look at an example:

<?php
// NUMBER
$amount = 0.13;

// REGULAR EXPRESSION
$regex = "/\B(?=(\d{3})+(?!\d))/i";
$usd = "$" . preg_replace($regex, ",", $amount);
echo $usd;
?>

Output:

$0.13

Format a Number to a Dollar Amount in PHP Manually

This method is equivalent to picking a lock with brutal force. This method gives you the advantage of using any format you want.

Let us look at an example:

<?php
// FOR A DOLLAR CURRENCY
function curformat ($amount) {
  //  SPLIT WHOLE & DECIMALS
  $amount = explode(".", $amount);
  $whole = $amount[0];
  $decimal = isset($amount[1]) ? $amount[1] : "00" ;

  //  ADD THOUSAND SEPARATORS
  if (strlen($whole) > 3) {
    $temp = ""; $j = 0;
    for ($i=strlen($whole)-1; $i>=0; $i--) {
      $temp = $whole[$i] . $temp;
      $j++;
      if ($j%3==0 && $i!=0) { $temp = "," . $temp; }
    }
    $whole = $temp;
  }

  //  RESULT
  return "\$$whole.$decimal";
}

//  UNIT TEST
echo curformat(100); // $100.00

Output:

$100.00

The above methods should format a number to a string showing dollars and cents.

There is another method called money_format, but it does not work on windows. We highly advise you not to use this function as it is deprecated.