How the what-if planner works
The planner treats your hypothetical courses exactly like real ones: it converts each grade to grade points, multiplies by credits, adds your already-earned points, and divides by your new total credits. Nothing about your past changes — you're only testing futures.
Projected GPA = (Current × Completed + Σ Grade points × Credits) ÷ (Completed + Σ Credits)
This is the fastest way to answer questions like "what if I get all B's?" or "can I afford one C if the rest are A's?" Try the pessimistic version first: if even your worst realistic case keeps you above your goal, you can relax.
Worked example
You have a 3.2 GPA after 45 credits. Next semester you plan Biology (4 credits), Chemistry (4 credits) and English (3 credits). You expect an A (4.0) in Biology, a B+ (3.3) in Chemistry and an A− (3.7) in English. Projected = (3.2 × 45 + 4.0 × 4 + 3.3 × 4 + 3.7 × 3) ÷ 56 = (144 + 16 + 13.2 + 11.1) ÷ 56 = 184.3 ÷ 56 = 3.29. A solid step up — and you can see exactly which course moves the needle most by changing one grade at a time.
Tips for realistic scenarios
Build three scenarios: optimistic, realistic and pessimistic. Weight your expectations by course difficulty and professor reputation, not hope. And remember that high-credit courses swing your GPA far more than 1-credit labs — protect those first.