It's difficult to determine which exam is easier as it depends on individual language abilities and preferences. However, some differences between the exams can be noted. IELTS tests proficiency in British English and includes four sections: listening, reading, writing, and speaking. TOEFL tests proficiency in American English and includes reading, listening, speaking, and writing sections. Duolingo's English Test is an online exam that evaluates a person's language abilities using a computer-adaptive test. Ultimately, the level of difficulty will vary based on individual circumstances.