Starting preparation for the International Physics Olympiad (IPhO) in grade 10 is feasible, even without prior calculus knowledge. A solid understanding of calculus is essential for physics, and several recommended resources can help build this foundation. Notable suggestions include the 3blue1brown and BetterExplained websites for conceptual understanding, along with MIT's single-variable calculus course for detailed study. For practical applications, OpenStax offers free textbooks on calculus and university physics, which are beneficial for both learning and practice. Additional resources like Physoly and AAPT's past exam archives provide valuable practice problems. While starting preparation may feel late for IPhO, it is never too late to enhance physics comprehension significantly.