GRE Quant: 15 Formulas You Need to Master for 2026

Over 200,000 test-takers sit for the GRE every year. Many find Quantitative Reasoning the toughest section. The GRE isn't an advanced math test, but it does demand quick recall of foundational concepts. Application of these concepts is key. On the shortened GRE, efficiency matters even more. You'll need to spot patterns and use the right formula fast. This guide lists 15 crucial GRE Quant formulas, ordered by how often they show up and how important they are. It'll help you get ready for the 2026-27 admissions cycle.

The Shortened GRE Quant Section: What Changed?

The GRE General Test, updated in September 2026, is much shorter. It went from almost four hours to under two. For the Quantitative Reasoning section, that means fewer questions, packed into less time. You still get two sections. Each has 12 questions and 21 minutes to complete them. Question types haven't changed: Problem Solving, Quantitative Comparison, and Data Interpretation. The core math — arithmetic, algebra, geometry, and data analysis — is all the same. You still need to know your formulas well. No topics were cut, just the number of questions. ETS provides an on-screen calculator; learn how to use it, but don't lean on it for every single calculation.

Frequently Tested Formulas: Arithmetic and Algebra

Most GRE Quant questions center on basic arithmetic and algebra. These aren't just about crunching numbers. They're about seeing how numbers and variables relate. Since these concepts pop up everywhere, these formulas are vital for your score.

1. Percent Change

• Formula: ((New Value - Original Value) / Original Value) * 100%
• Importance: Shows up constantly in data interpretation and word problems. You absolutely need to understand percentage increases and decreases.

2. Average (Arithmetic Mean)

• Formula: Sum of terms / Number of terms
• Importance: This is a basic building block for many stats questions. Often, it's combined with weighted averages or finding a missing number.

3. Simple Interest

• Formula: Interest = Principal * Rate * Time
• Importance: Directly applies to word problems about investments.

4. Quadratic Formula

• Formula: For ax^2 + bx + c = 0, x = (-b ± sqrt(b^2 - 4ac)) / 2a
• Importance: You might not always need the full formula, but recognizing quadratic patterns and factoring them is critical. Sometimes, when factoring isn't easy, you'll need this one.

5. Work Rate

• Formula: 1/T_total = 1/T_1 + 1/T_2 + ... (where T is time to finish a job)
• Importance: Classic work-rate problems require combining individual speeds. They're often about 'people working together' or 'pipes filling a tank'.

Geometry Essentials for GRE Quant

Geometry questions can feel tricky, but they usually test fundamental properties of shapes. Visualizing these ideas and knowing the right formulas can save you a lot of time. Remember, drawings are often not to scale unless they say so.

6. Area of a Triangle

• Formula: Area = 1/2 * base * height
• Importance: Extremely common. You'll use this formula for complex shapes by breaking them into triangles.

7. Pythagorean Theorem

• Formula: a^2 + b^2 = c^2 (for a right triangle, c is the hypotenuse)
• Importance: Essential for right triangles. Also vital for figuring out distances in coordinate geometry, like the distance between two points.

8. Area of a Circle

• Formula: Area = πr^2
• Importance: Appears often, sometimes with sectors or mixed with other shapes.

9. Circumference of a Circle

• Formula: Circumference = 2πr or πd
• Importance: Also common, especially for arc lengths or perimeters that include curves.

10. Volume of a Rectangular Solid/Cube

• Formula: Volume = length * width * height (or s^3 for a cube)
• Importance: Standard volume calculation, often in word problems about capacity.

Data Analysis and Statistics Formulas

The Data Analysis section checks your ability to read charts, graphs, and statistical measurements. Even though the shortened GRE has fewer Data Interpretation sets, knowing these statistical concepts is still key.

11. Standard Deviation

• Concept: Measures how spread out data is from the mean. A bigger standard deviation means data points are, on average, farther from the mean.
• Importance: You usually don't calculate this by hand. Instead, the test checks your understanding of its definition and how it works in data sets, often in Quantitative Comparison. Remember that adding or subtracting a constant from every value in a set doesn't change the standard deviation, but multiplying or dividing does.

12. Probability (Basic)

• Formula: P(Event) = (Number of favorable outcomes) / (Total number of possible outcomes)
• Importance: Basic probability questions show up regularly. Compound events, like 'and' or 'or' probabilities, also appear.

13. Combinations and Permutations

• Combinations (nCr): n! / (r! * (n-r)!) (order doesn't matter)
• Permutations (nPr): n! / (n-r)! (order matters)
• Importance: Less common than basic probability but definitely testable. Know when to use which and how to simplify factorials.

GRE Quant Formula Cheat Sheet (Partial)
| Concept           | Formula                                       | Notes                                  |
|-------------------|-----------------------------------------------|----------------------------------------|
| Percent Change    | (New - Original) / Original                   | Multiply by 100 for percentage         |
| Average           | Sum / Count                                   | Essential for data sets                |
| Area: Triangle    | 1/2 * base * height                           | Versatile for complex shapes           |
| Pythagorean Thm.  | a^2 + b^2 = c^2                               | Only for right triangles               |
| Work Rate         | 1/T_total = 1/T_1 + 1/T_2                     | For two entities working together      |

Advanced / Less Frequent but Still Important Formulas

These formulas might not be on every test, but knowing them gives you an edge. They often form the basis of tougher problems that separate the top scores.

14. Distance Formula (Coordinate Geometry)

• Formula: d = sqrt((x_2 - x_1)^2 + (y_2 - y_1)^2)
• Importance: This comes straight from the Pythagorean Theorem. You use it to find the distance between two points on a coordinate plane. It's essential for advanced geometry.

15. Compound Interest

• Formula: A = P(1 + r/n)^(nt)
• Importance: Not as common as simple interest, but compound interest problems can get complex. Know what the variables mean: A=amount, P=principal, r=annual rate, n=compounds per year, t=time in years.

Strategy for Formula Mastery

Just memorizing these isn't enough. You need to understand where they come from and when to use them. Lots of GRE problems ask you to turn a word problem into a math equation. That usually means knowing the right formula. Practice questions are key here. Use flashcards for active recall. Make your own formula sheet and add to it as you find new problem types. Think about why a formula works, not just what it is.

What to do this week

• Look over the 15 formulas. Pay extra attention to any you don't know well.
• Make flashcards for any formulas you need to really commit to memory.
• Work through at least 20 official GRE Quantitative Reasoning practice questions. For each, identify which formulas apply.
• Time yourself on a small Quant section (12 questions in 21 minutes) to get used to the test conditions.
• Find your 3 weakest formula areas and spend extra time practicing those concepts.

PrepGuin's Guided Roadmap offers adaptive drills and focused lessons to help you master these (and other) essential GRE Quant formulas. Use the Mistake Vault to track and fix your errors. You'll build confidence in every topic before your 2026 test.