How to Use number_format in PHP: Syntax and Examples

Use the number_format function in PHP to format a number with grouped thousands and decimal points. It takes the number, optional decimals count, decimal point character, and thousands separator character as arguments to customize the output.

Syntax

The number_format function formats a number with grouped thousands and decimal points.

• number: The number to format.
• decimals (optional): How many decimal digits to show.
• decimal_point (optional): Character to use for the decimal point.
• thousands_separator (optional): Character to use for thousands separator.

php

string number_format(float $number, int $decimals = 0, string $decimal_point = ".", string $thousands_separator = ",")

Example

This example shows how to format a number with 2 decimals, a dot as decimal point, and a comma as thousands separator.

php

<?php
$number = 1234567.891;
$formatted = number_format($number, 2, '.', ',');
echo $formatted;
?>

Output

1,234,567.89

Common Pitfalls

Common mistakes include:

• Not specifying decimals when you want decimal places, so the number rounds to an integer.
• Using wrong characters for decimal point or thousands separator, which can confuse readers.
• Passing non-numeric values, which causes warnings or unexpected results.

php

<?php
// Wrong: no decimals, output is rounded integer
$val1 = number_format(1234.56);
echo $val1; // Outputs: 1,235

// Right: specify decimals to keep decimal places
$val2 = number_format(1234.56, 2);
echo $val2; // Outputs: 1,234.56
?>

Output

1,235
1,234.56

Quick Reference

Parameter	Description	Default
number	The number to format	Required
decimals	Number of decimal digits	0
decimal_point	Decimal point character	"."
thousands_separator	Thousands separator character	","

Key Takeaways

Use number_format to add commas and decimals to numbers for better readability.

Always specify decimals if you want to keep decimal places; otherwise, it rounds to an integer.

Customize decimal and thousands separators to match your locale or style.

Avoid passing non-numeric values to prevent warnings or errors.