NEET chapter-wise weightage: where the 720 marks actually sit

How are NEET marks split between subjects?

NEET UG is 180 compulsory questions in 180 minutes: Physics 45, Chemistry 45 and Biology 90, split into Botany 45 and Zoology 45. Each correct answer is +4 and each wrong one is −1, so the paper is worth 720 marks and Biology alone is worth 360 of them.

That single fact settles most prioritisation arguments. A student who converts an extra five Biology questions gains 20 marks; the same effort in a light Physics unit might gain four. BrainStride is an AI tutor for JEE, NEET and Olympiad preparation that runs a 20-minute diagnostic, maps your weak chapters and writes a daily plan, with every solution checked by teachers — and this is exactly the arithmetic the plan runs every night.

One warning before the tables. NTA does not publish chapter weightage, and nobody outside NTA knows the 2027 paper. Everything below is our reading of recent papers, written as ranges on purpose. Ranges overlap and are rounded, so they will not add up neatly to 45 or 90 — that is honesty about the data, not an error.

Which Biology chapters repay the most revision?

Genetics and evolution, because it is both heavy and reasoning-based: a student who understands linkage, pedigree analysis and Hardy–Weinberg assumptions converts questions that pure memorisation misses. Human physiology is close behind and rewards the opposite habit — precise recall of sequences, values and NCERT diagram labels.

Ecology is the quiet one. It brings 6–9 questions in our analysis, it is short, and it is almost entirely NCERT recall. Students preparing in a hurry skip it because it feels unglamorous, then lose 24 to 36 marks in a paper where the cut-off for a government seat moves on ten.

The pattern repeats across the syllabus: the fastest marks are usually in the units that are easy to read and easy to postpone. Our NEET Biology page lists all 32 chapters with the mistake each one tends to catch.

How do you turn weightage into a revision order?

Multiply, don’t sort. A unit’s value to you is its weight multiplied by how much of it you are currently losing. A heavy unit you already score 90% in has almost nothing left to give; a mid-weight unit where you score 40% is where the next fifty marks live.

A rule of thumb that survives contact with a real timetable

1. List the heavy units — genetics and evolution, human physiology, ecology, cell structure, reproduction, plus mechanics, current electricity and modern physics in Physics.
2. Score yourself honestly on each, from your last two mocks rather than from memory.
3. Work the overlap first: heavy and weak. That is the shortest route to a better rank, and it is rarely the unit you feel like revising.
4. Protect the light units you already own. One timed set a fortnight keeps ecology or biomolecules from quietly decaying.
5. Re-score monthly. The list changes as you improve, which is the whole point.

Why chapter counts move every year

The paper is set fresh each year, so a unit that brought five questions last year may bring three this year. That is why every figure here is a range, and why a plan built on a single predicted count breaks. The mistake analysis approach treats weightage as a prior, not a promise, and updates the order from what you actually got wrong this week.