Free supplement calculators — protein, creatine, and caffeine. No signup, no email, no fluff. Your numbers stay in your browser.
Daily protein target
Based on body weight and your goal. Evidence range: 1.2–2.2 g per kg.
–g per day
Hitting that number is the hard part
A protein shake covers 24–30 g per serving. Whey after training is the simplest gap-filler. A typical scoop holds ~30 g, but labels vary — check yours. Plant-based? Pea and soy blends hit the same numbers; the per-meal target is what matters. Also fasting? Plan your eating window at IntermittentCalc.
Safe ceiling for healthy adults: 400 mg/day. Per-kg evidence range: 3–6 mg/kg for performance.
–mg per day, max
Caffeine half-life is roughly 5 hours. Cutting off by the time shown lets most of a dose clear before bed. Not medical advice — pregnancy, heart conditions, and anxiety medications change the math.
Count what's actually in your cup
Home-brewed coffee runs 80–120 mg per cup; pre-workouts range 150–350 mg. Black coffee during a fast is fine — plan your fasting hours at IntermittentCalc.