diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 5a528d8..d0d6c52 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -2090,8 +2090,7 @@ class PHPMailer
         foreach ($this->to as $toaddr) {
             $toArr[] = $this->addrFormat($toaddr);
         }
-        //Fold long lists the same way as the To header, mail() keeps CRLF + WSP folds intact
-        $to = trim(substr($this->addrAppend('To', $this->to), strlen('To:')));
+        $to = trim(implode(', ', $toArr));
 
         //If there are no To-addresses (e.g. when sending only to BCC-addresses)
         //the following should be added to get a correct DKIM-signature.
@@ -2648,18 +2647,17 @@ class PHPMailer
             $addresses[] = $this->addrFormat($address);
         }
 
-        //Fold between addresses so that no line exceeds the RFC 2822 line length limit
+        //Fold between addresses so that no line exceeds the RFC 5322 limit,
+        //leaving room for the comma at the end of a folded line
         $header = $type . ': ' . array_shift($addresses);
         $lineLength = strlen($header);
         foreach ($addresses as $address) {
-            //The address goes after ', ' and must still leave room for the ',' that ends
-            //the line if the next address gets folded
-            if ($lineLength + strlen(', ') + strlen($address) + strlen(',') > static::MAX_LINE_LENGTH) {
+            if ($lineLength + strlen($address) + 3 > static::MAX_LINE_LENGTH) {
                 $header .= ',' . static::$LE . ' ' . $address;
-                $lineLength = strlen(' ') + strlen($address);
+                $lineLength = strlen($address) + 1;
             } else {
                 $header .= ', ' . $address;
-                $lineLength += strlen(', ') + strlen($address);
+                $lineLength += strlen($address) + 2;
             }
         }