Best Calculators for the PE Exam 2026: All NCEES-Approved Models Compared

Why Your Calculator Choice Matters for the PE Exam

The PE (Professional Engineer) exam is the final step to earning your PE license — the credential that allows you to stamp drawings, approve engineering plans, and practice independently. Across 80 discipline-specific questions over 9 hours, you will solve problems in structural analysis, fluid mechanics, circuit theory, thermodynamics, environmental systems, and more. Every one of those problems requires a calculator.

Unlike the FE exam (where many candidates are students picking a calculator for the first time), most PE candidates already own an NCEES-approved calculator from their FE exam days. But here is the question worth asking: is the calculator you used for the FE still the best choice for the PE?

The PE exam is fundamentally different from the FE. It is discipline-specific, significantly longer (9 hours vs 5 hours 20 minutes), and tests deeper engineering knowledge. The problems are more complex, the calculations are more involved, and battery life matters more than ever. If your FE calculator was a basic TI-30XIIS, you may want to upgrade to a TI-36X Pro or Casio fx-991CW that can handle matrix operations, complex numbers, and numeric integration natively — functions you will actually need on the PE.

Complete List of NCEES-Approved Calculators

NCEES maintains a single approved calculator list that applies to both the FE and PE exams. Here is the complete list as of 2026:

Texas Instruments:

• TI-30X IIS (solar + battery)
• TI-30X IIB (battery only)
• TI-30XS MultiView (also available as on-screen digital calculator)
• TI-36X Pro

Casio:

• Casio fx-115 ES Plus (1st and 2nd editions)
• Casio fx-115 MS Plus (1st and 2nd editions)
• Casio fx-991 ES Plus (1st and 2nd editions)
• Casio fx-991 MS Plus (1st and 2nd editions)
• Casio fx-991 EX (ClassWiz)
• Casio fx-991 CW

Hewlett-Packard:

• HP 33s (discontinued)
• HP 35s (discontinued)

Important: NCEES states that different variations of these models (color, edition number) are generally accepted. However, any calculator not on this list — including graphing calculators, CAS models, and phone apps — will be confiscated at check-in. The digital TI-30XS MultiView is always available on-screen as a fallback.

Bottom line: Of the models listed above, the HP 33s and HP 35s are discontinued and should not be purchased. Everything else is readily available new from Amazon or office supply stores.

Side-by-Side Comparison

Key insight for PE candidates: Unlike the FE exam (which covers broad fundamentals), the PE exam goes deep into your specific discipline. Matrix operations matter for structural analysis (Civil), complex numbers matter for phasor analysis (Electrical), and numeric integration matters for fluid mechanics (Mechanical/Environmental). Choose a calculator that supports the functions your discipline demands.

Our Top 5 PE Exam Calculators for 2026

1. TI-36X Pro — Best Overall for PE

The TI-36X Pro is the most popular calculator among PE exam candidates, and it has earned that reputation. With a four-line MultiView display, built-in equation solver, matrix and vector operations, complex number arithmetic, and numeric integration/differentiation, it handles virtually every calculation type you will encounter on the PE exam — regardless of discipline.

Why PE candidates choose it: The four-line display is a game-changer during a 9-hour exam. You can see your input, intermediate steps, and results simultaneously without scrolling. When you are solving a system of equations for a truss analysis or computing the integral of a flow rate function, being able to verify your setup before pressing ENTER saves critical time and prevents errors.

Key specs for PE:

• Four-line MultiView display
• 3x3 matrix operations (add, subtract, multiply, determinant, inverse)
• Complex number arithmetic (rectangular and polar forms)
• Numeric integration and differentiation
• Equation solver (polynomial up to 3rd degree, system of linear equations)
• Unit conversions (22 built-in conversions)
• Vector operations (cross product, dot product)
• Statistics with regression

Discipline-specific strengths:

• PE Civil: Unit conversions between metric and US customary, matrix operations for structural analysis, integration for hydraulics
• PE Mechanical: Numeric integration for thermodynamic cycles, equation solver for heat transfer, statistics for quality/reliability
• PE Electrical: Complex numbers in rectangular/polar form for impedance and phasor analysis, matrix operations for network equations
• PE Chemical: Equation solver for mass/energy balances, integration for reaction kinetics, unit conversions
• PE Environmental: Integration for flow calculations, statistics for water quality data, unit conversions

Pros:

• Best combination of advanced functions in an NCEES-approved package
• Four-line display reduces errors during long calculations
• Affordable at $27.95
• Handles every PE discipline's core calculation needs
• Widely available with extensive YouTube tutorials

Cons:

• 3x3 matrix limit (the Casio fx-991CW does 4x4)
• Battery-only with solar backup — ensure fresh batteries for the 9-hour exam
• No natural textbook display (uses linear entry for fractions and exponents)

2. Casio fx-115ES Plus 2nd Edition — Best Budget Pick

At just $16.99, the Casio fx-115ES Plus 2nd Edition is the most affordable capable calculator on this list — and it punches well above its price. With 280+ functions, Natural Textbook Display, matrix/vector operations, complex numbers, and solar+battery dual power, it covers everything most PE candidates need at roughly half the price of alternatives.

Why budget-conscious PE candidates love it: If you already passed the FE with a different calculator and want a reliable backup or upgrade without spending much, the fx-115ES Plus delivers. The Natural Textbook Display shows fractions, integrals, and exponents exactly as they appear in your engineering textbooks and the PE Reference Handbook, reducing the mental translation between what you read and what you enter.

Key specs for PE:

• 280+ functions
• Natural Textbook Display (fractions, exponents, integrals shown naturally)
• Matrix and vector operations
• Complex number calculations
• Numeric integration and differentiation
• Equation solving (simultaneous and polynomial)
• Solar + battery dual power (critical for 9-hour exam)
• 40 scientific constants built in

Pros:

• Most affordable option at $16.99
• Natural Textbook Display matches reference handbook notation
• Solar + battery dual power — virtually impossible to run out of power
• 280+ functions cover all PE disciplines
• Slim, lightweight design

Cons:

• Smaller display than TI-36X Pro (2 lines vs 4 lines)
• Slightly less intuitive menu navigation than TI models
• Fewer unit conversions built in compared to TI-36X Pro

3. Casio fx-991CW — Most Powerful NCEES-Approved Calculator

The Casio fx-991CW is the newest and most advanced calculator on the NCEES approved list. With 540+ functions — nearly double the next closest model — it is the closest thing to a computing powerhouse that NCEES allows. If you want every possible advantage within the rules, this is it.

What sets it apart: The fx-991CW can handle 4x4 matrix operations — the only NCEES-approved calculator that goes beyond 3x3. For PE Civil candidates solving structural systems with 4 unknowns, or PE Electrical candidates working with 4-node circuit networks, this is a tangible advantage. The high-resolution 4-tone display provides excellent readability even in the variable lighting conditions of a testing center.

Key specs for PE:

• 540+ functions (most of any approved calculator)
• High-resolution 4-tone display
• 4x4 matrix operations (unique among NCEES-approved models)
• Complex number arithmetic
• Numeric calculus (integration and differentiation)
• Spreadsheet-style data viewing (up to 5 columns x 45 rows)
• QR code function for linking to online math resources (not usable during exam, but helpful during study)
• Equation solver and inequality solver
• Solar + battery dual power

Discipline-specific advantages:

• PE Civil: 4x4 matrices for larger structural systems without manual partitioning
• PE Electrical: Complex number operations plus 4x4 matrices for multi-node networks
• PE Mechanical: Spreadsheet mode for organizing thermodynamic property tables during calculations
• PE Chemical: 4x4 system solver for complex mass balance equations
• PE Environmental: Statistical functions with larger data sets for environmental monitoring analysis

Pros:

• 540+ functions — most powerful approved calculator by far
• 4x4 matrix operations (exclusive advantage)
• Excellent high-resolution display
• Solar + battery dual power
• Spreadsheet-style data entry for organized calculations
• Competitively priced at $20.99

Cons:

• Newer model with fewer online tutorials compared to TI-36X Pro or fx-115ES Plus
• Menu-driven interface has a learning curve
• Some functions are buried in submenus that take time to navigate

4. TI-30XIIS — Best for Simple, Reliable Calculations

The TI-30XIIS is the calculator equivalent of a reliable pickup truck — it does the basics well, it is affordable, and it will not let you down. While it lacks the advanced functions of the TI-36X Pro or Casio models (no matrix ops, no complex numbers, no integration), it handles arithmetic, trigonometry, logarithms, and statistics with zero fuss.

Who should consider it: If your PE discipline does not require heavy matrix operations or complex number arithmetic — or if you prefer to do advanced calculations by hand using the PE Reference Handbook and only need a calculator for number crunching — the TI-30XIIS is a solid, distraction-free choice. Some PE candidates actually prefer its simplicity because there are fewer menus to accidentally get lost in during a high-pressure exam.

Key specs for PE:

• 2-line display (entry + result)
• Basic scientific functions (trig, log, exponents, roots)
• One and two variable statistics with regression
• Fraction calculations
• Solar + battery dual power
• Lightweight and compact

Pros:

• Extremely simple and reliable — no confusing menus
• Solar + battery dual power
• Affordable at $17.99
• Familiar to almost everyone — minimal learning curve
• Fast for basic calculations (fewer keystrokes for common operations)

Cons:

• No matrix operations
• No complex number arithmetic
• No numeric integration/differentiation
• No equation solver
• 2-line display limits visibility of multi-step calculations
• May be insufficient for PE Electrical and PE Civil structural problems

5. Casio FX-991ES Plus 2nd Edition — Premium International Variant

The Casio FX-991ES Plus 2nd Edition (note the uppercase "FX") is the international version of the fx-115ES Plus, with 417 functions compared to 280. It shares the same Natural Textbook Display and solar+battery power but adds extra capabilities including additional equation solving modes and enhanced statistical functions.

Why consider it over the fx-115ES Plus: With 417 functions versus 280, you get more equation-solving flexibility and additional statistical tools. The redesigned color-coded keypad also makes it easier to quickly locate function keys — a small but real advantage when you are 7 hours into a 9-hour exam and your eyes are tired. It bridges the gap between the fx-115ES Plus and the fx-991CW.

Key specs for PE:

• 417 functions
• Natural Textbook Display
• Matrix and vector operations
• Complex number calculations
• Numeric integration and differentiation
• Equation solver (simultaneous equations, polynomials)
• Solar + battery dual power
• Color-coded keypad for faster key identification

Pros:

• More functions than the fx-115ES Plus at a mid-range price
• Natural Textbook Display matches reference handbook notation
• Color-coded keypad reduces hunting for keys
• Solar + battery dual power
• Non-programmable — zero risk of NCEES compliance issues

Cons:

• At $28.94, it is close to the TI-36X Pro price ($27.95) which offers a 4-line display
• Fewer tutorials available than TI-36X Pro
• 3x3 matrix limit (same as most models, unlike the fx-991CW's 4x4)

Which Calculator Should You Choose?

Use this decision framework based on your PE discipline and situation:

Did you pass the FE recently and still have your calculator? -> If it is a TI-36X Pro, Casio fx-115ES Plus, or Casio fx-991 series: keep it. Muscle memory from hundreds of hours of FE study is invaluable. Do not switch calculators just for the PE.

Are you taking the PE Civil exam? -> Get the TI-36X Pro ($27.95) for its unit conversions and matrix operations, or the Casio fx-991CW ($20.99) if you need 4x4 matrices for structural systems.

Are you taking the PE Electrical exam? -> Get the TI-36X Pro ($27.95) or Casio fx-991CW ($20.99). Both handle complex numbers natively, which is essential for phasor and impedance calculations.

Are you taking the PE Mechanical or Chemical exam? -> The TI-36X Pro ($27.95) covers everything you need. Its equation solver and integration functions handle thermodynamic and mass balance problems well.

Are you taking the PE Environmental exam? -> The TI-36X Pro ($27.95) or Casio fx-115ES Plus ($16.99) both work well. Environmental PE relies on statistics, unit conversions, and basic integration — both models handle these easily.

Are you on a tight budget? -> The Casio fx-115ES Plus ($16.99) is an excellent calculator at an unbeatable price. Solar+battery power means it will never die during your 9-hour exam.

Do you want maximum capability? -> The Casio fx-991CW ($20.99) has 540+ functions and 4x4 matrix operations — the most powerful calculator NCEES allows — at a surprisingly low price.

Our overall recommendation: For most PE candidates, the TI-36X Pro at $27.95 is the best choice. It balances advanced functions, an excellent 4-line display, widespread tutorial support, and affordability. If you want the absolute most power, the Casio fx-991CW at $20.99 is actually cheaper and has more functions — but the TI-36X Pro's 4-line display and more intuitive interface give it the edge for a 9-hour exam.

The Digital TI-30XS: Your Built-In Backup

One advantage PE candidates have over many other exam takers: NCEES provides a digital TI-30XS MultiView calculator built into the exam software. This on-screen calculator appears on your computer screen and functions identically to the physical TI-30XS model.

When to use the digital calculator:

• Your physical calculator's batteries die
• You want a second calculator running a separate calculation while your physical one holds a result
• You accidentally left your calculator at home (rare, but it happens)

Limitations of the digital calculator:

• Every input requires a mouse click — significantly slower than physical keys
• No tactile feedback means more input errors
• Over 9 hours, clicking a mouse calculator becomes genuinely fatiguing
• It is a TI-30XS (basic model) — no matrix operations, no complex numbers, no integration

Bottom line: Treat the digital calculator as emergency backup only. Bring a physical calculator and fresh batteries.

FE vs PE: Why Your Calculator Strategy Should Evolve

If you are moving from the FE to the PE, here is how your calculator needs change:

Key takeaway: If you used a basic calculator like the TI-30XIIS for the FE and passed, you can use it for the PE — but you are leaving efficiency on the table. A 30-second matrix solve on the TI-36X Pro could take 5 minutes by hand. Over 80 questions in 9 hours, those minutes add up.

Discipline-Specific Calculator Tips

PE Civil

Civil PE covers structural, geotechnical, transportation, water resources, and construction. Your calculator will see heavy use for:

• Structural analysis: Matrix operations for solving systems of equilibrium equations. The TI-36X Pro handles 3x3; the Casio fx-991CW handles 4x4.
• Hydraulics: Numeric integration for flow rate calculations and Manning's equation variations.
• Unit conversions: Civil engineering constantly switches between feet/meters, psi/kPa, gallons/liters. The TI-36X Pro has 22 built-in conversions.
• Statistics: Regression analysis for pavement design data and water quality parameters.

Recommended: TI-36X Pro or Casio fx-991CW

PE Mechanical

Mechanical PE covers HVAC, thermal/fluids, and machine design. Key calculator needs:

• Thermodynamics: Interpolation between table values (use the equation solver), integration for cycle analysis.
• Heat transfer: Solving simultaneous equations for thermal resistance networks.
• Machine design: Stress calculations, fatigue analysis with statistical factors.
• Fluid mechanics: Numeric integration for pressure distributions, Bernoulli equation variations.

Recommended: TI-36X Pro

PE Electrical

Electrical PE covers power, electronics, controls, and communications. This discipline has the highest calculator demands:

• Complex numbers: Phasor analysis, impedance calculations, AC power — almost every problem involves complex arithmetic. Your calculator must handle complex numbers natively.
• Matrix operations: Node voltage and mesh current methods for multi-node circuits.
• Polar/rectangular conversion: Switching between forms for different problem types.
• Trigonometric functions: Phase angle calculations, power factor analysis.

Recommended: TI-36X Pro or Casio fx-991CW (both handle complex numbers; the fx-991CW adds 4x4 matrices for larger circuit networks)

PE Chemical

Chemical PE covers mass/energy balances, thermodynamics, kinetics, and process design. Key needs:

• Equation solving: Multi-component mass and energy balance systems.
• Integration: Reaction rate kinetics, heat exchanger design equations.
• Unit conversions: Switching between molar, mass, and volumetric flow rates.
• Statistics: Process control and quality analysis.

Recommended: TI-36X Pro or Casio fx-115ES Plus

PE Environmental

Environmental PE covers water/wastewater, air quality, solid waste, and remediation. Key needs:

• Statistics: Environmental monitoring data analysis, regulatory compliance calculations.
• Integration: Flow calculations, pollutant transport equations.
• Unit conversions: mg/L to ppm, cubic meters to gallons, various concentration units.
• Logarithms: pH calculations, first-order decay equations.

Recommended: TI-36X Pro or Casio fx-115ES Plus

Battery Life: A Critical PE Exam Consideration

The PE exam lasts up to 9 hours — nearly double the FE. Battery failure is not just an inconvenience; it could cost you months of preparation. Here is how each calculator handles power:

All five models use solar+battery dual power. This means even if the battery is weak, overhead lighting in the testing center powers the solar cell. The risk of total power failure during the exam is extremely low — but install fresh batteries the week before exam day anyway. A CR2032 or LR44 costs under $3. That is cheap insurance.

Pro tip: When you install a fresh battery, turn the calculator on and verify all functions work. Occasionally a new battery can be dead on arrival. Test it at home, not at the testing center.

Exam Day Calculator Checklist

Use this checklist the night before and morning of your PE exam:

• Physical calculator — NCEES-approved model with fresh batteries (installed within the past week)
• Verify it is on the approved list — check the exact model against the NCEES calculator policy
• Test all critical functions — matrix operations, complex numbers, integration (whatever your discipline requires)
• Clear all memory — the proctor will inspect your calculator; pre-clear it to avoid delays at check-in
• Practice with the on-screen TI-30XS — know how to use it in case your physical calculator fails (NCEES provides a tutorial)
• Bring your government-issued ID — required for check-in (not calculator-related, but commonly forgotten)
• Clean the screen and keys — 9 hours of use means oils from your fingers will smudge the display
• Know your testing center policies — some Pearson VUE locations have specific rules about items at your workstation
• No backup calculator at workstation — NCEES allows only one physical calculator; leave the backup in your locker

Common Calculator Mistakes on the PE Exam

PE candidates report these recurring calculator errors. Knowing them in advance helps you avoid them:

1. Forgetting to switch between degree and radian mode. Most PE problems use degrees for angles, but some calculus-based problems expect radians. Check your angle mode before every trig calculation. On the TI-36X Pro, press MODE and verify DEG is selected.

2. Not knowing how to enter complex numbers. PE Electrical candidates lose time fumbling with complex number entry. On the TI-36X Pro, press 2ND then the imaginary unit key to enter complex numbers. Practice entering numbers like 3+4i and 5 angle 30 degrees before exam day.

3. Relying on the calculator for problems that are faster by hand. Simple multiplication, percentages, and basic unit conversions are often faster by hand or mental math. The PE Reference Handbook has conversion tables — use them. Save the calculator for matrix solves, integration, and complex arithmetic.

4. Running out of time because of slow calculator work. With 80 questions in 9 hours, you have about 6 minutes per question. If a calculator operation takes more than 30 seconds, you are probably doing it wrong. Know the fastest keystroke sequence for your most common operations.

5. Not clearing previous calculations. Unlike financial calculators, scientific calculators do not always clear previous inputs when you start a new calculation. Always press CLEAR or AC before starting a new problem, especially after matrix or complex number operations.

A Note on Discontinued HP Models

The HP 33s and HP 35s remain on the NCEES approved list but have been discontinued by Hewlett-Packard. If you already own one from your FE exam days and are comfortable with it, you can absolutely use it for the PE. These were solid scientific calculators with RPN entry.

However, do not buy an HP 33s or HP 35s secondhand for the PE exam. You risk receiving a unit with worn keys, a fading display, or a dying battery compartment — problems you definitely do not want to discover during a 9-hour exam. The TI-36X Pro and Casio models are better values in every way for a new purchase.

Free PE Exam Prep Resources

A great calculator is only part of the equation. Pair it with solid study materials for your specific PE discipline:

• Free PE Civil Study Guide — Comprehensive content covering all PE Civil exam topics
• Free PE Mechanical Study Guide — Thermal/fluids, HVAC, and machine design coverage
• Free PE Electrical Study Guide — Power systems, electronics, controls, and communications
• Free PE Chemical Study Guide — Process design, thermodynamics, and kinetics
• Free PE Environmental Study Guide — Water, air quality, solid waste, and remediation
• Free PE Civil Practice Questions — Unlimited attempts with detailed answer explanations
• AI Tutor — 10 free questions per day — ask it to walk you through calculator keystrokes for any PE problem

The AI tutor is especially useful for calculator practice. Ask it questions like "Walk me through how to solve a 3x3 matrix on the TI-36X Pro for structural analysis" or "How do I enter complex numbers in polar form on the Casio fx-991CW for an impedance problem?" and it will give you step-by-step keystroke instructions.

Final Verdict

For most PE exam candidates, the TI-36X Pro ($27.95) is the best choice. Its four-line display, matrix operations, complex number handling, equation solver, and broad tutorial support make it the most versatile NCEES-approved calculator for any PE discipline. It handles the deep, discipline-specific calculations the PE demands while remaining intuitive enough that you will not waste time navigating menus during the exam.

If you want the most powerful calculator NCEES allows, the Casio fx-991CW ($20.99) offers 540+ functions and 4x4 matrix operations at an even lower price — an excellent choice for PE Civil and PE Electrical candidates who need larger matrix capability.

If you are on a tight budget, the Casio fx-115ES Plus ($16.99) covers all the essentials with solar+battery power and Natural Textbook Display.

And if you already have an NCEES-approved calculator from your FE exam? Use it. Familiarity and muscle memory are worth more than any feature gap, especially over a grueling 9-hour exam.

Whichever calculator you choose, buy it at least 2 months before your PE exam date and use it for every practice problem. The PE exam rewards speed and accuracy — and both come from hours of practice with your specific calculator.

PE CivilFree exam prep with practice questions & AI tutor