How to delete COOKIES in PHP?

Use the setcookie() function but with negative value in the third parameter (which is the expires ), you can also use unset() with the variable $_COOKIE to delete the key in the current execution:

function unsetcookie($key, $path = '', $domain = '', $secure = false, $httponly = false)
{
    if (isset($_COOKIE[$key])) {
        setcookie($key, null, -1, $path, $path, $domain, $secure, $httponly);
        unset($_COOKIE[$key]);
    }
}

//Elimina o cookie pro path atual
unsetcookie('meucookie');

//Elimina o cookie pro path raiz
unsetcookie('meucookie', '/');

//Elimina o cookie de um domínio quando estiver em um subdomínio por exemplo: bar.foo.com
unsetcookie('meucookie', '/', 'foo.com');

As in the documentation example: link

The response from the @GuilhermeNascimento answers the question very well, but I would like to add an extra.

When it comes to Cookies, I do not know if the correct way would be to say "Delete Cookies". What is usually done to make Cookie "Deleted" is "invalidate".

I say this because the most common way is to set a negative value for the $expire parameter. This will make the browser understand that Cookie has already "expired" and will not send it to the server.

In a simplified way, you delete a cookie like this:

 setcookie('quero_apagar_isso', null, -1);

Logically thought, one would think that unset($_COOKIE['quero_apagar_isso']) would work, but this is not true.

The variable $_COOKIE is just as read-only because it references something from the client.

The only case where unset will work with a Super Global variable is in the $_SESSION variable.

Only reflect: If you used unset($_GET['id']) , the id parameter would disappear from the url? . Obviously not. Similarly Cookie will not cease to exist just because you deleted a value that references it in PHP.

In the same way that you could only delete the id parameter of a url through redirection, you will only be able to delete the Cookie by setting it in a way that the Browser considers invalid.

Do as follows:

<?php

unset($_COOKIE['nome_cookie']);
setcookie('nome_cookie', null, -1, '/');

Facinho, my dear. The command is unset($_COOKIE['nomeDoCookie']);

Ready will already help you with your problem.

That's good luck!