PHP number format with number_format() function

The PHP number_format() function is used to format a number with thousands and decimal separators.

The function syntax is as shown below:

number_format(
    float $num,
    int $decimals = 0,
    ?string $decimal_separator = ".",
    ?string $thousands_separator = ","
): string

The function accepts 4 parameters:

The float number to format (required)
The int number of decimal digits in the format (optional)
The string for decimal separator (optional)
The string for thousands separator (optional)

Although the function accepts a float type data for the number to format, it will return a string to include the decimal and thousand separators in the number.

Here’s how you call the function:

// 👇 no decimal format: 10,999,888
echo number_format(10999888);

// 👇 2 decimal digits: 10,999,888.00
echo number_format(10999888, 2);

// 👇 1 decimal digits: 10,999,888.3
echo number_format(10999888.333, 1);

// 👇 use custom separators: 10#999#888;33
echo number_format(10999888.333, 2, ";", "#");

Keep in mind that when you pass a decimal separator, you also need to pass the thousands separator.

When you pass only three parameters, the number_format() function will generate a warning and return NULL:

// 👇 the following call generates a warning
number_format(10999888.333, 2, ";");

// Warning: Wrong parameter count for number_format()
// in index.php on line 1

To change the thousand separator only, you still need to pass the original decimal separator value, which is a dot (.) symbol.

Here’s how to change only the thousand separator using number_format():

echo number_format(10999888.333, 0, ".", "#");

// 👉 result: 10#999#888

If you’re using PHP v8, you can also pass named arguments to skip passing $decimals and $decimal_separator as shown below:

echo number_format(
    num: 10999888.333, 
    thousands_separator: "#"
);

// 👉 result: 10#999#888

And that’s how you format a number using PHP number_format() function.

For more information, see the PHP number_format() documentation.

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