How to Remove Spaces from a String in PHP

By the end of this page, you will understand how to remove spaces from strings in PHP, when to use str_replace() versus regular expressions, and how to avoid common mistakes when working with whitespace.

In PHP, removing spaces from a string usually means creating a new version of the string without certain characters.

The most common tool for this is str_replace(), which replaces one substring with another. If you replace a space (" ") with an empty string (""), all normal space characters are removed.

$string = "this is my string";
$result = str_replace(" ", "", $string);

echo $result; // thisismystring

This matters because string cleaning is very common in programming. Developers often remove spaces when:

• normalizing user input
• generating usernames or slugs
• cleaning imported data
• comparing text values
• formatting IDs, phone numbers, or codes

A key detail is that a space is not always the same as whitespace.

• A normal space is " "
• Other whitespace characters include:
  • tabs (\t)
  • newlines (\n)
  • carriage returns (\r)

So if your goal is only to remove visible space characters, str_replace(" ", "", $string) is enough. If you want to remove all whitespace characters, a regular expression is usually better.

Think of a string like a row of tiles:

t h i s _ i s _ m y _ s t r i n g

Each _ represents a space. Removing spaces means scanning through the row and taking out every tile that matches a space.

• str_replace() says: "Whenever you see this exact tile, remove it."
• preg_replace() says: "Whenever you see any tile matching this pattern, remove it."

So:

• use str_replace() for exact characters
• use preg_replace() for flexible pattern matching

The most common syntax is:

str_replace(search, replace, subject)

To remove all normal spaces:

$string = "this is my string";
$result = str_replace(" ", "", $string);

echo $result;

Output:

thisismystring

Example: remove spaces from user input

$username = "john doe";
$cleanUsername = str_replace(" ", "", $username);

echo $cleanUsername; // johndoe

Example: remove all whitespace, not just spaces

$text = "this\tis\nmy string";
$result = preg_replace('/\s+/', , );

 ; 

Consider this code:

$string = "this is my string";
$result = str_replace(" ", "", $string);
echo $result;

Here is what happens step by step:

1. $string is assigned the value:

   "this is my string"
   

2. str_replace(" ", "", $string) is called.

   • Search for: " "
   • Replace with: ""
   • In this string: "this is my string"

3. PHP looks through the string and finds every normal space character.

4. Each space is replaced with an empty string, which means it is removed.

5. The new value becomes:

   "thisismystring"
   

6. That result is stored in $result.

Removing spaces from strings is useful in many practical situations.

1. Cleaning form input

Users may enter values with spaces you do not want.

$postalCode = "12 345";
$cleanPostalCode = str_replace(" ", "", $postalCode);

2. Formatting phone numbers or IDs

$phone = "123 456 7890";
$cleanPhone = str_replace(" ", "", $phone);

3. Creating usernames

$name = "Jane Doe";
$username = strtolower(str_replace(" ", "", $name));
// janedoe

4. Data import and cleanup

CSV or copied data often contains inconsistent spacing.

$productCode = ;
 = (, , );

In real PHP projects, developers usually combine string cleanup with validation and normalization.

Common pattern: normalize before saving

$emailInput = " john doe@example.com ";
$normalized = trim($emailInput);

If spaces inside the value are not allowed:

$normalized = str_replace(" ", "", trim($emailInput));

Common pattern: guard clause for empty input

function normalizeCode(string $code): string
{
    $code = trim($code);

    if ($code === '') {
        return '';
    }

    return str_replace(' ', '', $code);
}

This avoids extra processing on empty values.

Here are common mistakes beginners make when removing spaces in PHP.

1. Using trim() when you want to remove all spaces

trim() only removes whitespace at the beginning and end.

Broken expectation:

$string = "this is my string";
echo trim($string); // still contains inner spaces

Use this instead:

echo str_replace(" ", "", $string);

2. Forgetting that strings are immutable in practice

str_replace() returns a new string. It does not permanently modify the variable unless you assign the result.

Broken code:

$string = "a b c";
str_replace(" ", "", $string);
echo $string; // a b c

Correct:

str_replace() vs preg_replace()

// Remove all normal spaces
$result = str_replace(' ', '', $string);

// Remove spaces from the same variable
$string = str_replace(' ', '', $string);

// Remove whitespace at the start and end only
$result = trim($string);

// Remove all whitespace: spaces, tabs, newlines
$result = preg_replace('/\s+/', '', $string);

Quick rules

• Use str_replace() for exact character replacement.
• Use trim() for outer whitespace only.
• Use preg_replace('/\s+/', '', ...) for all whitespace.
• Reassign the result if you want to update the variable.

Common examples

str_replace(' ', '', 'a b c');        // abc
();                    
(, , ); 

How do I remove all spaces from a string in PHP?

Use:

$result = str_replace(' ', '', $string);

This removes all normal space characters.

How do I remove all whitespace, not just spaces?

Use a regular expression:

$result = preg_replace('/\s+/', '', $string);

This removes spaces, tabs, and newlines.

Does trim() remove all spaces in PHP?

No. trim() only removes whitespace from the beginning and end of a string.

Does str_replace() modify the original string?

No. It returns a new string. Assign the result back to a variable if needed.

Which is better: str_replace() or preg_replace()?

If you only need to remove normal spaces, str_replace() is better because it is simpler and clearer.

Can I remove only leading and trailing spaces?

• str_replace() — the core PHP function for replacing exact text in strings.
• preg_replace() — useful when you need pattern-based string replacement.
• trim() — related because it removes whitespace from the edges of a string.
• string manipulation in PHP — broader topic covering modification and formatting of text.
• regular expressions in PHP — important when simple replacement is not enough.
• string comparison — often combined with normalization like removing spaces.
• form input validation — user input is often cleaned before validation or storage.