You can use a calculator on ACT Mathematics only — not on English, Reading, or Science. Most standard scientific and graphing calculators are permitted. A handful are banned outright. This guide covers the full approved and prohibited list, the best calculator choice for the test, and how to use it strategically on test day.
The ACT permits calculators on the Mathematics section only. The 60-minute, 60-question Math section is the only section where you're allowed to have a calculator on your desk. English, Reading, and Science are calculator-free — even if you have yours with you.
The ACT's permitted calculator categories are broad. Here's what you can bring:
If your calculator is one of these categories and doesn't appear on the banned list below, you can bring it. The ACT doesn't publish a comprehensive approved list — instead it publishes a banned list and assumes everything else is fine.
The single most important restriction: no Computer Algebra System (CAS). CAS calculators can perform symbolic algebra — solve equations for x, factor polynomials, simplify expressions — which effectively does the work of many ACT Math questions for you. Any calculator with CAS is banned.
The TI-Nspire CX CAS is banned. The TI-Nspire CX (non-CAS) is allowed. Check your specific model before test day — they look nearly identical on the outside.
Beyond CAS calculators, the ACT also prohibits: devices with wireless or Bluetooth capability, tablets, laptops, phones used as calculators, calculators with a built-in camera, and devices with a QWERTY keyboard. The rule of thumb: if it looks like a communication device, it's not allowed.
Proctor discretion applies at the testing center. If a proctor is uncertain about your calculator, they may ask you to put it away. Bringing a well-known permitted model like the TI-84 avoids any ambiguity. If you bring an unusual model, print the ACT's calculator policy page and have it ready — though the proctor's decision is final on test day.
The TI-84 Plus CE is the most commonly recommended calculator for the ACT — not because it's the most powerful, but because it's familiar, reliable, and covers every function you'll actually need on the test.
The ACT Math section tests pre-calculus at most. You don't need a CAS to solve ACT problems — you need a calculator that handles arithmetic quickly, can graph functions for coordinate geometry problems, and can evaluate expressions without errors. The TI-84 does all of that. Most students already own one from high school math class, which means zero learning curve on test day.
The CE version has a color screen and rechargeable battery. The older TI-84 Plus Silver Edition is also permitted and works the same way. Either is fine.
A scientific calculator — TI-30XS, Casio fx-115ES Plus, or equivalent — is sufficient for ACT Math if you're already comfortable with it. The main limitation is the lack of graphing, which matters for maybe 3–5 questions on a typical test. If you don't have time to learn a new graphing calculator before the test, stick with what you know.
If you don't own a graphing calculator and don't want to buy one, check with your school. Many schools loan TI-84s for standardized testing. Some ACT test centers provide calculators — but don't count on it. Check with your test center before the exam rather than assuming you'll be covered.
Don't buy an expensive new calculator the week before the test. ACT Math rewards understanding over calculation horsepower — a student who knows the concepts with a TI-30 will outperform a student who doesn't with a TI-84. Familiarity with your device matters more than the device's feature list. Also don't bring a backup phone calculator. Phones aren't permitted in the testing room even in airplane mode.
Two things to verify the night before: (1) Your calculator model isn't on the banned list — look up the exact model number, not just the brand. (2) Your batteries are fresh or your calculator is fully charged. Proctors won't provide batteries or allow phone calculators as backup. Bring a spare set of AAA batteries if your calculator uses them. The TI-84 Plus CE has a rechargeable battery — charge it the night before.
Owning a permitted calculator doesn't automatically help your score. How you use it matters — and overusing it actually costs time.
ACT Math is designed so that most problems can be solved faster by recognizing a pattern or applying a formula than by calculating. A question like "what is 15% of 60?" is faster to reason (10% = 6, half again = 9, total = 9) than to type into a calculator. On a 60-question, 60-minute test, every second counts.
Reserve the calculator for genuinely messy arithmetic: multi-step decimal calculations, square roots you don't know by heart, evaluating trigonometric expressions, or checking an answer you solved algebraically.
The graphing function earns its keep on problems involving parabolas, circles, or systems of equations. If a problem gives you an equation and asks about its graph — vertex, intercepts, shape — graphing it directly and reading values from the screen is faster and more reliable than working it out algebraically. Practice this skill before test day so you're not fumbling with the graphing menu under time pressure.
Whatever calculator you plan to bring, use it during your practice tests — not a phone or a different model. Your muscle memory for the keystrokes matters. Finding the sin button or switching between radian and degree mode should be automatic by test day, not a thing you're figuring out mid-section.
Pre-Algebra and Algebra I — mostly mental math territory. Percentages, ratios, basic equations. Use the calculator to verify, not to solve. If you're reaching for it on a basic linear equation, that's a signal to practice the concept more.
Algebra II and Functions — evaluating f(x) at specific values, checking function composition results. Calculator helps here. So does the table feature on graphing calculators — plug in a function and read off values instead of computing them by hand.
Geometry — area, perimeter, volume formulas often involve decimals once you plug in the numbers. Let the calculator handle the arithmetic once you've set up the formula. For coordinate geometry, graphing the equation is often the fastest path to the answer.
Trigonometry — this is where the calculator is most essential for many students. Evaluating sin(37°), finding an angle using inverse trig — these aren't values most people know by heart. Just confirm you're in degree mode (not radian) before the Math section starts.
Statistics — mean, median, standard deviation questions appear on the ACT. The TI-84's STAT function handles these directly. Know how to enter a list and run 1-Var Stats before test day.
After the test, your Math section score contributes to your composite. Knowing what is the high score for act helps you set a realistic Math target based on where you need your composite to land. To understand how your Math score compares to all test-takers, what is the score act shows percentile breakdowns for every section score. For national average context across all sections, see what is the average score on act test. And once you've tested, check when will the act scores come out so you know exactly when to expect your Math section result.