David Lang wrote
Rod Speed wrote
Stuart Noble wrote

Here's the thing. Pro door hangers use a plane because often they
don't have the space to lay the door out on sawhorses or whatever and,
because they do sod all else all day, they're pretty good at it. For the
rest of us, and I include chippies who don't hang doors all day long,
the circ saw method is pretty foolproof

Like hell it is. The problem with using a circular saw is that it is
MUCH harder for someone who has never done a door before to work out how
much to take off. MUCH safer to trim the door gradually with a plane
until it clears the new carpet or tiles.

Or do it properly and get it right first time.

Very unlikely the OP would manage to do that
and even if he does, there is a lot more work to
make a sawboard that he obviously doesn’t have
than to do it with an electric plane more safely
for the door and get a perfectly acceptable result.