Solving the Call to Undefined Function Password_Hash() Error: A Comprehensive Guide

In this guide, we will walk you through the process of resolving the "Call to undefined function password_hash()" error in PHP. This error occurs when the PHP version in use is not compatible with the password_hash() function. We'll discuss why this error occurs, how to check your PHP version, and how to upgrade your PHP version to solve this error. Additionally, we'll cover some frequently asked questions related to this topic.

Table of Contents

Understanding the Error

The password_hash() function is used to create a new password hash using a strong one-way hashing algorithm. This function is available in PHP 5.5.0 and later versions. If you are using an earlier version of PHP, you will encounter the "Call to undefined function password_hash()" error. To resolve this error, you need to upgrade your PHP version to at least 5.5.0.

Checking Your PHP Version

Before upgrading your PHP version, you need to check the current version of PHP installed on your system. You can do this by creating a new PHP file and adding the following code:

echo 'Current PHP version: ' . phpversion();

Save this file as phpinfo.php and upload it to your web server. Then, open this file in your browser to see the current PHP version.

Alternatively, you can check the PHP version via the command line by running the following command:

php -v

Upgrading Your PHP Version

Once you've determined your current PHP version, follow the steps below to upgrade it:

Backup your website: Before making any changes, make sure to create a backup of your website files and database.

Upgrade PHP on your local development environment: If you are using a local development environment like XAMPP or WAMP, download and install the latest version of the software.

Upgrade PHP on your hosting server: If your website is hosted on a server, you'll need to upgrade PHP through your hosting provider. Most hosting providers offer an option to upgrade PHP in their control panels. If you're not sure how to do this, consult your hosting provider's documentation or contact their support team.

  1. Test your website: After upgrading your PHP version, thoroughly test your website to ensure everything is working as expected.

Learn more about upgrading PHP


1. What is the password_hash() function used for?

The password_hash() function is used to securely hash passwords using a strong one-way hashing algorithm. This makes it more difficult for attackers to crack the hashed passwords if they gain access to your database.

2. What are some alternatives to password_hash() if I cannot upgrade my PHP version?

If you cannot upgrade your PHP version, you can use the crypt() function as an alternative. However, it is strongly recommended to upgrade your PHP version to take advantage of the improved security features provided by the password_hash() function.

3. How can I verify a password hashed with password_hash()?

You can use the password_verify() function to verify a password against a hashed password. This function returns true if the provided password matches the hash, and false otherwise.

PHP 5.5.0 and later versions provide the PASSWORD_DEFAULT and PASSWORD_BCRYPT constants for use with the password_hash() function. It is recommended to use PASSWORD_DEFAULT, as it automatically uses the most secure algorithm available in your PHP version.

5. Can I use the password_hash() function with older PHP versions?

Yes, you can use the password_compat library, which provides a compatibility layer for older PHP versions (5.3.7 and later) to use the password_hash() function. However, it is still recommended to upgrade your PHP version for the best security features.

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.