Best Approved Calculators for the FE Exam With Description and Features

In the engineering and tech domain, it is always better to trust your instruments more than you trust your intuitions. But you need a perfect and accurate instrument to rely on.

A range of potential aspects significantly impacts your FE exam performance and results. One vital factor is choosing the best approved calculator for the FE exam. Your calculator choice can either make or break your FE exam performance.

With a lot of brain work already involved in the FE exam, you can only afford to do simple calculations manually. It will weaken your focus on the core exam areas and drain your limited time to complete your FE exam.

Let’s look at the following NCEES® approved calculators for the FE exam.

FX-115 ES PlusCasio$19-$30
TI-36X ProTexas Instruments$20-$25
HP 35SHewlett-Packard$200-$290
fe Exam approved calculators

To help you choose the best calculator for FE exam, we will discuss NCEES® approved and recommended calculator options in the following blog post. Let’s discuss all the available options in detail.

4 Best NCEES® Approved FE Exam Calculators

To ensure the integrity of FE exams, NCEES® restricts your calculator choice by strictly directing you to choose FE approved calculators. The list of NCEES® approved calculators is revised each year by NCEES® that includes the most appropriate and best calculators for the FE exam. You are strictly obliged to use calculators approved by NCEES®.

Best FE approved Calculators

For the year 2022, the NCEES® accepts the following list of calculators as listed on its official website.

  1. Casio fx-115 ES Plus
  2. Texas Instruments TI-36X Pro
  3. Hewlett Packard HP 35S
  4. Casio FX-991

Let’s discuss the practicality and features of these calculators allowed in the FE exam.

1. Casio FX-115 ES Plus

Casio FX-115 ES Plus Calculator

You can use different FX-115 models like FX-115 MS, MS Plus, MS SR, ES, and ES Plus.

The most recent FX-115 model is FX-115 ES Plus, which you can easily find in the market or order online. The other older models are complex and rare to find currently in the market. So it’s irrelevant to discuss those options as FX-115 ES Plus is presently the most readily available FE exam-approved calculator.

Its salient features include:

Basic functions

  • Basic Mathematical Calculations
  • Total 252 Functions
  • Time Value Calculation
  • Power Function (Square, Cube, Power X)
  • Power Function (Square Root, Cube Root, X Root)
  • Trigonometric Functions and Inverse Trigonometric Functions
  • Parabolic Functions and Inverse Parabolic Functions
  • Hyperbolic Functions and Inverse Hyperbolic Functions
  • Exponential Function
  • Log Function
  • Combination and Permutation
  • Factorization of Prime Number
  • Greatest Common Divisor
  • Least Common Multiple
  • Random Number or Integer Generation
  • Addition/Subtraction
  • Multiplication/Division

More Advanced functionalities

  • System of Linear Equations
  • Solution of Inequalities
  • Matrix & Vector Calculations

Physics- and chemistry-related functions

  • Scientific Constants
  • Metric conversion function

As far as the user experience and overall capability is concerned, Casio FX-115 ES Plus has some limitations. But some of its advanced features make it relevant for the FE exam. On top of everything, its price point is the most convincing reason that ensures maximum value for money for the students. But if you have no budget limit, it’s better to opt for Texas Instruments TI-36X Pro.

2. Texas Instruments TI-36X Pro

Texas Instruments TI-36X Pro

Texas Instruments NCEES®-approved calculators, TI-30X and TI-36X, and all their respective models are readily available in the market. The 36X is a bit more expensive than its TI-30X counterpart but offers a much better display.

Its salient features include:

  • Review and edit previous inputs by scrolling on the home screen
  • Copy & Paste values into new calculations
  • MathPrint™ option to view calculations in mathematical formats, including answers in the form of pi, roots, and fraction
  • Solving system of linear equations
  • Derivatives and Integrals of real numbers
  • Reciprocals and factorial of numbers
  • Vector calculations
  • Matrix calculations
  • Toggle button to convert fractions, roots, and pi to decimal and back to mathematical notations
  • Percentage and Fraction conversions
  • conversion between improper fractions and mixed numbers
  • Auto-simplified answers for fractions
  • Random number generation
  • All Functions accessible via keys or through drop-down menus
  • Permutations & Combinations
  • Trigonometric, Hyperbolic and Parabolic functions
  • Logathermatic operations
  • The degree to Radian conversions and vice versa
  • The degree to minutes & seconds conversions and vice versa
  • Save Formulas and constant values
  • Storing variables
  • Interconversion of decimal, hexadecimal, octal, and binary number systems
  • Linear regression and distributed function
  • Save up to eight pending results or processes
  • Allows up to 23 nested parentheses
  • Error recovery option
  • Auto Turn Off
  • Eight variables for store values or constants
  • Multiple scientific notations

With all the features as mentioned above, students prefer the TI-36X Pro over Casio for two exceptional reasons:

TI offers power-off memory preservation, unlike Casio. The most significant disadvantage of Casio is it erases the stored answer and calculation history if you accidentally power off the calculator or it turns off automatically after 7 minutes.

The TI calculator holds your answer and calculation history if you shift between the different modes. For example, if you perform any calculation in Matrix mode and change the mode to Vector Calculations, your answer and calculation history will be preserved. But this is not the case with Casio.

3. Hewlett Packard HP 35S

Hewlett Packard HP 35S

The feature-rich HP 35S is the next-in-line best calculator for the FE exam. The said model replaces the older 33S with better functionalities and options. HP 33S, an old model, is obsolete in most aspects.

Remember that these NCEES®-approved calculators do not offer the RPN functionality (2 enter, 2 +, equals 4), and you need to train your mind and fingers to get used to this void.

Its salient features include:

  • Scientific and statistical functions
  • Solution of a system of linear equations
  • Derivatives and Integrals
  • Complex number operations
  • Vector calculations
  • Matrix calculations
  • Unit conversions
  • Approx. 30 KB of memory for programs and data
  • Trigonometric, Hyperbolic, and parabolic functions
  • Logathermatic operations
  • The degree to Radian conversions and vice versa
  • The degree to minutes & seconds conversions and vice versa
  • Save Formulas and constant values
  • Storing variables
  • Interconversion of decimal, hexadecimal, octal, and binary number systems
  • Linear regression and distributed function
  • Conversion of fractions, roots, and pi to decimal and back to mathematical notations

HP 35s wins the race regarding ergonomics with a user-friendly keyboard layout. In features and utility, it competes with the TI-36X. The TI-36X has a 4.6/5.0 rating on Amazon. The HP 35s is slightly behind Texas Instruments with an overall rating of 4.1/5.0. Declaring the best between both of these options is a subjective matter. But the capabilities of both calculators are up to the mark. The only disadvantage is its higher price point.

4. Casio FX-991

Casio FX-991

You can choose FX-991 instead of simple FX-991 for much better ergonomics, enhanced and contrasting button colors, and better-built quality. You can avoid mistakenly hitting the wrong buttons in a hurry with improved ergonomics and better color adoption.

Its salient features include:

  • Basic mathematical calculations
  • Scientific calculations
  • Differentiation and Integration
  • Matrix & Vector Calculations (Addition, Multiplication, & Determinant)
  • System of Linear Equations
  • Logarithmic calculations
  • Trigonometric functions
  • Basic Statistics
  • Permutation and Combination
  • Exponential functions
  • Complex number calculations
  • Fractions to Decimal Conversions and vice versa
  • Mathematical Notations to Decimal Conversions and vice versa
  • Featuring 9 variables to save values

Among all the Casio FX-991 models, FX-991EX is the best and most capable calculator for scientific calculations. FX-991 EX also gives tough competition to Texas Instruments’ finest calculator, the TI-36X Pro. The capabilities and features of FX-991EX are equal to TI-36X Pro and offer better response and intuitive performance than its TI counterpart.

Expert Advice – Tips for Effectively Using the FE Exam Calculators

Tips for Effectively Using the FE Exam Calculators

Below are some vital tips that will help you further handle your calculator with limited chances of mistakes during your FE exam.

  1. Understand and practice the layout of the buttons to help save time and avoid errors during the subconscious use of the calculator in the exam. While some problems are “plug and chug,” you must still plug in all those numbers. Even the most minor error can cost you valuable time.
  2. Most of us hardly skim the surface of what our devices are capable of, whether they are smartphones or calculators. Go to the depth of your calculator and explore all its features. Reviewing your user handbook and exploring the available functionalities will take a little time and effort.
  3. Use the same calculator during your FE exam preparation that you will use in the exam. It is crucial to get used to the calculator you will use in the exam.
  4. If you are using a new calculator, ensure that you go through all the important functions, understand its digital interface, learn how to access all the functions, and what are the default conversions methods. Some of the significant functions that you must explore for your FE exam include:
    • Vector Additions & Multiplications
    • Matrix Additions, Multiplications, & Determinants
    • Calculations involving complex numbers
    • Logarithmic calculations
    • Permutations & Combinations
    • Integral functions
    • Derivatives
    • Store and recall saved variables
    • Conversion of polar to rectangular numbers and vice versa
    • Switching from degrees to radians and vice versa
    • Finding solutions to the systems of linear equations involving two and three variables
  5. Finally, on exam day, ensure that you have inserted new batteries in your calculator.

To avoid facing trouble and panic during your FE exam, don’t forget to cross-check the checklist of the most important items to bring to the FE Exam.


Appearing in the NCEES® FE exam is the most vital prerequisite in your journey to get the PE license in the future. One of the essential tools candidates must choose wisely is their calculator for their FE exam. By choosing the best calculator for FE exam you can spare the burden of manual calculations and redirect your efforts to face the biggest challenges in the FE Exam preparation.

It’s pretty simple to choose from the list of one of the best calculators for the FE exam. Just direct your purchase decision around a decision matrix that helps you discover the calculator with vital functionalities like matrix addition, matric multiplication, matrix determinants, solution of linear systems of equations, and the easiest ways to find definite derivatives and integral functions.

Among all the discussed options, we can easily say that the TI-36X calculator beats its competitors in all aspects, including features, capabilities, and pricing. After using all these calculators, we feel it safe to comment that Texas Instruments TI-36X is undoubtedly a winner. You can learn more about this best calculator for the FE exam in our detailed blog related to TI-36X Pro tips and tricks.

Wasim Asghar – P.E, P.ENG, M.ENG

Licensed Professional Engineer in Texas (PE), Florida (PE) and Ontario (P. Eng) with consulting experience in design, commissioning and plant engineering for clients in Energy, Mining and Infrastructure.