GRE vs. GMAT: format and structure of both the GMAT and the GRE

Can you tell me about the format and structure of both the GMAT and the GRE so that I can take an informed decision?

Since the two tests are both taken on a computer, you must examine the specific contents of each test in order to make the proper decision.To begin with, compare the sections on each test:

GMAT
GMAT Test Section	# of Questions	Question Types	Timing
Analytical Writing Assessment (AWA)	1 topic	1. Analysis of Argument	30 Minutes
Integrated Reasoning	12 questions	1. Multi-Source Reasoning 2.Graphics Interpretation 3.Two-Part Analysis 4.Table Analysis	30 Minutes
Quantitative	31 Questions	1.Problem Solving 2.Data Sufficiency	62 Minutes
Verbal	36 Questions	1.Reading Comprehension 2.Critical Reasoning 3.Sentence Correction	65 Minutes
Total Exam Time (not incl. breaks)			3 hours 07 minutes

GRE
GRE Test Section	# of Questions	Question Types	Timing
Analytical Writing Measure	2 Topics	1.Analyze an Issue 2.Analyze an Argument	30 Minutes 30 Minutes
Quantitative (x2)	20 Questions in each of the two sections (40 total)	1.Multiple-Choice: Select One 2.Multiple-Choice: Select One or More 3.Numeric Entry 4.Quantitative Comparison	35 Minutes per section (70 min. total)
Verbal (x2)	20 Questions in each of the two sections (40 total)	1.Text Completion 2.Sentence Equivalence 3.Reading Comprehension	30 Minutes per section (60 min. total)
Total Exam Time			3 hours 45 min.

Each test has Quantitative, Verbal and Writing sections, the types of questions within either Verbal or Quant section between the two tests are not similar.

Quantitative Section

One important difference between the GMAT and the GRE, especially helpful for those who hate doing (complex) math mentally is that the GRE provides an on-screen calculator for use during the Quantitative sections, while the GMAT does not.

The body of knowledge tested in the Quantitative sections of each exam is quite similar: questions in both tests are based on high school level arithmetic, algebra, and geometry. The most common question type on each test is multiple-choice, which are problems in which you are presented with a question and several answer choice options. Note that the math in the GMAT is considered more challenging than that of the GRE by a fair margin.