Untitled

<!DOCTYPE>
<html lang="pl">
<head>
    <meta charset="utf-8">
<title>temp</title>
<style>
</style>
</head>
<body>
<?php
if(!empty($_POST['XD'])){
    $XD = $_POST['XD'];
    $licz = $_POST['licz'];
    if ($licz == "q"){
        $kel = $XD+273.15;
        echo $kel;
    }
    elseif ($licz == "p"){
        $far=$XD*1.8+32;
        echo $far;
    }
}
?>
<form action="" method="POST">
Wpisz temperaturę <input type="number" step="0.1" name="XD"<br>
<br></label><input type="radio" name="licz" value="q">Kelwiny</label>
<br></label><input type="radio" name="licz" value="p">Farenheit</label><br>
<input type="submit" value="Obliczaj"><br>

</body>
</html>