The casual science student stops at textbooks. The contender grinds here. Let's keep this simple and straightforward.
Select the way you want to study, then jump into focused resources below.
Fast question practice for rapid recall and exam rhythm.
Deep topic study for long answers, structure, and confidence.
Start with Easy, Medium, or Hard questions. Choose an answer to see whether it's correct and read the explanation immediately.
Solve MCQs by difficulty with instant feedback.
Open MCQ-focused Learn Hub and revision notes.
Start from Practice, choose Easy, Medium, or Hard, then submit typed answers checked to 3 significant figures unless stated otherwise.
Submit typed numeric answers, checked to 3 significant figures, with instant feedback.
Open Theory-focused notes: equations, method, exam tips, misconceptions.
Pick a section, then a year. Original practice papers written in the style and difficulty of each IJSO era — not reproduced official past papers. Submit to see your score and full explanations.
Multiple-choice papers, one mark each, no penalty for wrong answers.
Typed numeric answers checked to 3 significant figures.
A focused list of books to use after your fundamentals are strong.
Built by medalists, for the next generation of medalists.
BDJSO Grinder is a non-profit initiative built on one simple belief: talent shouldn't be limited by access. Every explanation, every trick, and every practice question on this site exists for one reason — to hand every serious science student a clear, honest path toward the podium at the International Junior Science Olympiad, at zero cost.
This isn't recycled content or a generic quiz bank. BDJSO Grinder was founded by IJSO medalists who remember exactly what it feels like to be one topic away from a breakthrough, and every resource here — the MCQs, the theory sets, the chapter notes, the book list — is personally verified by IJSO medalists before it ever reaches a student. That's our quality bar: if it wouldn't help a medal-track student, it doesn't go on the site.
We keep the grinding simple, honest, and relentless — because that's what actually gets results. We know how hard this journey is, and we're here to help you cross that finish line. Let's get to work.