PHP number_format(): Thousands Separator and Decimals

number_format($number, $decimals) returns the number as a string with a thousands separator and a fixed number of decimals: number_format(1234567.891, 2) returns "1,234,567.89". With one argument it rounds to a whole number: number_format(1234567.891) is "1,234,568".

<?php
$amount = 1234567.891;

echo number_format($amount), "\n";            // no decimals
echo number_format($amount, 2), "\n";         // 2 decimals
echo number_format($amount, 2, ',', '.'), "\n"; // European style
echo number_format(0.129, 2), "\n";
echo number_format(-1234.567, 1), "\n";

The four parameters

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

The third argument is the character between the whole part and the decimals, the fourth the character between groups of three digits. Either can be any string, including an empty one or a multibyte character. Edit the separators below to see each style:

<?php
$n = 1234567.891;

echo number_format($n, 2, '.', ','), "  US, UK, Japan\n";
echo number_format($n, 2, ',', '.'), "  Germany, Spain, Italy, Brazil\n";
echo number_format($n, 2, ',', ' '), "  France, Russia, Poland\n";
echo number_format($n, 2, '.', "'"), "  Switzerland\n";
echo number_format($n, 2, '.', ''), "  no separator\n";

Locale data (CLDR) uses a narrow no-break space (U+202F) for French and a no-break space (U+00A0) for Russian, so a number never wraps across two lines. In HTML, pass "\u{202F}" or "\u{00A0}" as the separator instead of a plain space.

Format a number without a thousands separator

Pass '' as the fourth argument. You get a plain number with a fixed number of decimals, the shape payment gateways, CSV exports and <input type="number"> values expect:

<?php
$prices = [5, 19.9, 1234.5];

foreach ($prices as $p) {
    echo number_format($p, 2, '.', ''), "\n";
}

// Cents as an integer, for APIs that want the smallest unit
echo (int) round(19.9 * 100), "\n";

For the last line, round() before the cast matters: 19.9 * 100 is stored as 1989.9999999999998, and (int) alone would cut it to 1989.

How number_format rounds

number_format() rounds half away from zero, the way round() does, so 0.5 becomes 1 and -2.5 becomes -3. It also corrects the tiny binary error in values like 2.675, which is why it can disagree with sprintf('%.2f'):

<?php
foreach ([0.5, 1.5, 2.5, -2.5] as $x) {
    echo $x, " => ", number_format($x), "\n";
}

echo "\n";
echo number_format(2.675, 2), "  number_format\n";
echo sprintf('%.2f', 2.675), "  sprintf\n";
echo round(2.675, 2), "  round\n";

// PHP 8.3: negative decimals round to tens, hundreds, thousands
echo number_format(1234567, -3), "\n";

2.675 cannot be stored exactly in binary; the stored value is a hair below it. sprintf() formats that stored value and gets 2.67, while number_format() and round() treat it as the 2.675 you wrote. If you need a specific rounding rule, call round(), floor() or ceil() yourself first (see rounding and math) and pass the result to number_format().

Format money and other currencies

number_format() knows nothing about currencies, so you add the symbol yourself. Put negative signs before the symbol, and remember that yen has no decimals:

<?php
function money(float $amount, string $symbol = '$'): string
{
    $sign = $amount < 0 ? '-' : '';
    return $sign . $symbol . number_format(abs($amount), 2);
}

echo money(1499.5), "\n";
echo money(-20), "\n";
echo money(1234.5, '€'), "\n";

// Japanese yen: no decimals, 円 after the number
echo number_format(1980), "円\n";
echo '¥' . number_format(128000), "\n";

For locale-aware output with the right symbol position for every country, the intl extension's NumberFormatter does the whole job:

$fmt = new NumberFormatter('de_DE', NumberFormatter::CURRENCY);
echo $fmt->formatCurrency(1234.5, 'EUR'); // 1.234,50 € (a no-break space before €)

It requires the intl extension, which is not installed everywhere, so number_format() with your own symbol is the portable choice.

The result is a string, not a number

This is the most common bug with number_format(): formatting a value and then calculating with it. "1,234.50" is not a numeric string, so PHP reads only the 1 before the comma:

<?php
echo number_format(1234.5, 2) + 1;

Warning: A non-numeric value encountered in /home/index.php on line 2
2

Passing such a string back into number_format() is worse: it throws TypeError: number_format(): Argument #1 ($num) must be of type int|float, string given. Keep the raw number for math and format only at the moment you print. If you receive a formatted string from a form or a file, strip the separators first:

<?php
$total = 1234.5;
$display = number_format($total, 2);      // for output only

echo $display, "\n";
echo number_format($total + 100, 2), "\n"; // math on the number, then format

// Turning "1,234.50" back into a float
$input = '1,234.50';
$value = (float) str_replace(',', '', $input);
var_dump($value);

// European input "1.234,50"
$eu = '1.234,50';
$value = (float) str_replace(['.', ','], ['', '.'], $eu);
var_dump($value);

For padding, alignment or a plus sign in front of the number, use sprintf() instead; it does not add thousands separators, but it controls width and sign.