Hello Aspirant,

See there is no any fixed amount of time for completing the NEET UG syllabus because it depends upon the capability of student, talking about the score, then 651 is quite a decent score which cannot be achieved until and unless the concepts are thoroughly cleared. So roughly speaking for an average student, if he/she devotes at least-4-5 hours a day then to understand the entire syllabus of NEET UG it will take around 1.5 years to complete the syllabus as it consists of class 11th and 12th syllabus both.

For your reference I am mentioning down the syllabus of NEET UG :-

@Physics

> Physical world and measurement

> Electrostatics

> Kinematics

> Current Electricity

> Laws of Motion

> Magnetic Effects of Current and Magnetism

> Work, Energy and Power

> Electromagnetic Induction and Alternating Currents

> Motion of System of Particles and Rigid Body

> Electromagnetic Waves

> Gravitation

> Optics

> Properties of Bulk Matter

> Dual Nature of Matter and Radiation

> Thermodynamics, Oscillations and Waves

> Atoms and Nuclei

> Behaviour of Perfect Gas and Kinetic Theory

> Electronic Devices

@Chemistry

> Some Basic Concepts of Chemistry

> Solid State

> Structure of Atom

> Solutions

> Classification of Elements and Periodicity in Properties

> Electrochemistry

> Chemical Bonding and Molecular Structure

> Chemical Kinetics

> States of Matter: Gases and Liquids

> Surface Chemistry

> Thermodynamics

> General Principles and Processes of Isolation of Elements

> Equilibrium

> p-Block Elements

> Redox Reactions

> d and f Block Elements

> Hydrogen

> Coordination Compounds

> s-Block Element (Alkali and Alkaline earth metals)

> Haloalkanes and Haloarenes

> Some p-Block Elements

> Alcohols, Phenols and Ethers

> Organic Chemistry- Some Basic Principles and Techniques

> Aldehydes, Ketones and Carboxylic Acids

> Hydrocarbons

> Organic Compounds Containing Nitrogen

> Environmental Chemistry

> Biomolecules, Polymers and Chemistry in Everyday Life

@Biology

> Diversity in Living World

> Reproduction

> Structural Organization in Animals and Plants

> Genetics and Evolution

> Cell Structure and Function

> Biology and Human Welfare

> Plant Physiology

> Biotechnology and Its Application

> Human Physiology

> Ecology and Environment

You can also check out NEET Knockout package for your preparation

https://learn.careers360.com/knockout-neet-may/

I hope this information helps you.

Good Luck!!