If English isn't your first language, you'll likely need to prove your proficiency, and the two most accepted tests are the IELTS and the TOEFL. Both are respected worldwide, so the real question is which one plays to your strengths.
Format and style
The TOEFL is fully computer-based and heavily multiple-choice, with a strong academic focus. The IELTS offers a face-to-face speaking section with a real examiner and a mix of question types. If you're more comfortable speaking to a person than a microphone, IELTS may suit you better; if you prefer a consistent on-screen experience, TOEFL might.
Scoring and requirements
IELTS is scored on a band scale from 0 to 9, while TOEFL uses a 0 to 120 scale. Universities publish minimum scores for each, so check the requirements of your target programmes before deciding — occasionally an institution only accepts one of the two.
Choosing your strategy
Take a full-length practice test for each under timed conditions. Your scores and, just as importantly, how comfortable you felt, will usually point to a clear winner. Then commit to that test and build a focused prep plan around its specific sections.
Whichever you choose, consistency beats cramming — steady daily practice over a few weeks delivers the best results.