Confused describes the person having the feeling: "I'm confused by these instructions." Confusing describes the thing that causes it: "These instructions are confusing." The <em>-ed</em> form goes with the experiencer, the <em>-ing</em> form with the source — so a timetable is confusing, and you are confused.
The core difference
This is one instance of a pattern that runs right through English adjectives: bored/boring, interested/interesting, excited/exciting, frightened/frightening. The -ed form reports a feeling. The -ing form reports the cause of that feeling.
- The passengers were confused. (they felt it)
- The announcement was confusing. (it caused it)
How each one behaves
Confused normally attaches to people or animals, and takes by or about:
- I'm confused about which form I need.
- She looked confused by the question.
- Half the class was confused after the first lesson.
Confusing attaches to whatever is doing the damage — a document, a rule, a layout, a person's explanation — and often takes for:
- The pricing page is confusing.
- It's confusing for new starters that two systems share a login.
- He gave a confusing answer and then left.
The test
Ask: is this thing feeling something, or causing something? A feeling needs -ed; a cause needs -ing.
A quicker version for the sentence in front of you: try replacing the word with puzzled. If that works, use confused. Try replacing it with unclear. If that works, use confusing. "The map was ___" — the map is unclear, not puzzled, so: confusing.
Where it gets more interesting
Two crossovers are perfectly correct, and knowing them keeps you from over-applying the rule.
A person can be confusing. If someone's explanations leave others baffled, they are a confusing teacher — they are the cause. "He's confusing" and "he's confused" are both grammatical and mean opposite things about who is struggling.
A thing can be confused. Here confused carries an older sense — muddled, disordered, jumbled together. A confused argument is one whose own logic is tangled; a confused account of events is incoherent. This is not the emotion sense, and it is not an error.
The mistake that shows up most
Saying "I am confusing" when you mean you don't understand. To a listener, that says you are the one causing the trouble. The same reversal produces "I'm boring" for "I'm bored" and "I'm embarrassing" for "I'm embarrassed" — and in each case it says something unintended and slightly unfortunate about you.
Also watch the pairing of subject and preposition: things are confusing for people; people are confused by things.
Frequently Asked Questions
Is it "I am confused" or "I am confusing"?
I am confused, if you mean you don't understand something. "I am confusing" means you are the one causing confusion in other people, which is rarely what you want to say.
Can a person be confusing?
Yes. If someone's explanations leave others lost, they are confusing — they are the source. "She's a brilliant researcher but a confusing lecturer."
What does "a confused report" mean?
A muddled or incoherent one. Applied to things rather than people, confused carries the older sense of disordered: "the witness gave a confused account of the evening."