D&Dtools

Benefit

Your rage begins at any time you wish, even when
it’s not your turn or when you’re surprised. You can activate
your rage as a free action in response to another’s action. Thus,
you can gain the benefits of rage in time to prevent or ame-
liorate an undesirable event. For example, you can choose to
enter a rage when an enemy attacks you, or casts a spell at you
(to gain the benefits of a higher Constitution or your bonus
on Will saves) before you know the results of the attack. You
must be aware of the attack, but you may be flat-footed.

Normal

you may only enter a rage during your turn