How to Get the Length of an Integer in PHP?

In PHP, you can get the length of an integer in the following ways:

• Converting to String and Calling strlen();
• Looping and Removing Digits Off the End;
• Calculating the Length Mathematically.

Converting to String and Calling strlen()

You can simply convert the integer to a string and call the strlen() function on it to find the total number of digits in the integer:

function intLen(int $num) {
    return strlen((string) abs($num));
}

echo intLen(0); // 1
echo intLen(-0); // 1
echo intLen(-12345); // 5
echo intLen(12345); // 5

Calling abs() on the integer is needed so that the minus symbol is removed from a negative integer prior to converting the integer to a string. Otherwise, the minus symbol (-) will be converted to string as is and will be counted in the string length.

Looping and Removing Digits Off the End

You can simply create a loop, and remove the last digit from the integer in each iteration till there are no digits left. In each iteration you can increment a counter, which would give you the total number of digits in the integer:

function intLen(int $num) {
    $len = 0;

    do {
        // take last digit off `$num`
        $num = (int) ($num / 10);
        // increment counter
        $len++;
    } while ($num !== 0);

    return $len;
}

echo intLen(0); // 1
echo intLen(-0); // 1
echo intLen(-12345); // 5
echo intLen(12345); // 5

Calculating the Length Mathematically

You can calculate the number of digits in an integer in the following way:

function intLen(int $num) {
    return ($num === 0)
        ? 1
        : ceil(log10(abs($num) + 1))
    ;
}

echo intLen(0); // 1
echo intLen(-0); // 1
echo intLen(-12345); // 5
echo intLen(12345); // 5

The check for 0 is necessary as log10(0) is equal to -INF.