ACT Calculator Policy: What's Allowed, What's Not & Which Calculator to Use

Calculator rules on the ACT sound simple — bring a calculator, use it on math. But every year, students show up on test day with the wrong calculator, or with a calculator they've barely used, or without fresh batteries. And every year, those small mistakes cost real points.

The ACT's calculator policy has specific rules about what's allowed and what isn't. Getting this right isn't complicated, but it does require knowing the details. Here's everything you need to know — including our recommendation for which calculator to actually use.

The Basic Rule: Math Section Only

Let's start with the most fundamental rule: calculators are only permitted on the ACT Math section.

You cannot use a calculator on English, Reading, or Science. If a student pulls out a calculator during any of those sections, the proctor will likely confiscate it, and the student could face dismissal from the test.

During the Math section, calculator use is completely optional. No question on the ACT requires a calculator — every problem can be solved by hand. However, a calculator can significantly speed up arithmetic, graphing, and certain types of problem-solving. For most students, using a calculator wisely is a real advantage.

The key word is "wisely." We'll come back to that.

What Calculators Are Allowed

The ACT has a relatively permissive calculator policy compared to some other standardized tests. Here's what's approved:

Graphing Calculators (Most Popular Choice)

Graphing calculators are allowed and are by far the most commonly used option on the ACT. The following models are among the most popular approved calculators:

• •TI-84 Plus (and TI-84 Plus CE) — This is the gold standard. If you're buying a calculator for the ACT, this is our recommendation.
• •TI-83 Plus
• •TI-73
• •Casio fx-9750GII and similar Casio graphing models
• •HP Prime (with certain restrictions — see below)

Scientific Calculators

Basic scientific calculators (non-graphing) are also allowed. These include models like:

• •TI-30X IIS
• •TI-36X Pro
• •Casio fx-115ES Plus

Scientific calculators are perfectly adequate for the ACT, though they lack the graphing and programming capabilities that make graphing calculators more versatile.

Four-Function Calculators

Simple four-function calculators (add, subtract, multiply, divide) are technically allowed but offer almost no advantage. We don't recommend them — if you're going to bring a calculator, bring one that can do more than basic arithmetic.

What Calculators Are NOT Allowed

This is where families need to pay close attention. Bringing a prohibited calculator to the ACT can result in the device being confiscated, the student not being able to use any calculator at all during the Math section, or in extreme cases, dismissal from the testing session.

Calculators With CAS (Computer Algebra System)

This is the most important prohibition. Calculators with Computer Algebra System (CAS) capability are not allowed on the ACT.

CAS calculators can perform symbolic algebra — they can factor expressions, solve equations symbolically, and manipulate variables in ways that go beyond numerical computation. The ACT considers this an unfair advantage.

The most commonly encountered banned calculators include:

• •TI-Nspire CAS (note: the regular TI-Nspire without CAS is allowed)
• •TI-89 Titanium
• •TI-92
• •HP Prime in CAS mode (some HP Prime models can toggle CAS on/off — it must be off)
• •Casio ClassPad and other Casio CAS models

This is the mistake we see most often. A student has been using a TI-89 or TI-Nspire CAS in their math class all year, assumes it's fine for the ACT, and doesn't find out it's prohibited until they're at the test center on a Saturday morning. By then, it's too late.

If your child uses a CAS calculator in school, they need a separate, approved calculator for the ACT — and they need to practice with it well before test day.

Devices That Aren't Calculators

The following are explicitly prohibited:

• •Cell phones — Even if your phone has a calculator app, it cannot be used. Phones should be off and stored away during the entire test.
• •Laptops, tablets, or computers of any kind
• •Smartwatches (Apple Watch, Fitbit, etc.) — These must be removed before the test
• •Calculators with QWERTY keyboards (like the TI-92)
• •Calculators that make noise (unless the sound can be turned off)
• •Calculators that have paper tape
• •Calculators that can access the internet or communicate wirelessly

The Proctor Has Final Say

It's worth noting that individual proctors have the authority to determine whether a specific calculator is permitted. If a proctor is unfamiliar with your child's calculator model and isn't sure whether it's allowed, they may not permit its use. This is another reason we recommend the TI-84 — it's so commonly used that every proctor recognizes it as approved.

Our Recommendation: The TI-84 Plus CE

If you're wondering which calculator to buy for the ACT, the answer is straightforward: the TI-84 Plus CE.

Here's why:

• •Universally approved. No proctor will question it. No confusion about CAS capabilities.
• •Most commonly used. The TI-84 is the standard in most high school math classrooms, which means your child may already know how to use it.
• •Powerful enough. It handles graphing, statistics, trigonometric functions, and everything else the ACT Math section might throw at a student.
• •Not overpowered. Unlike CAS calculators, it won't be confiscated or questioned. It does exactly what's allowed and nothing that isn't.
• •Color screen and rechargeable battery (CE model). The updated CE version has a sharper display and USB charging, so no worrying about dead batteries on test day (though we still recommend charging it the night before).

The TI-84 Plus CE typically costs $120–$140 new, though used models and school-year sales often bring it lower. If your child already has a TI-83 Plus or an older TI-84, those work perfectly fine too — there's no need to upgrade unless they want the color screen and rechargeable battery.

The Golden Rule: Use What You Know

Here's the most important piece of calculator advice we give our students, and it has nothing to do with which model you buy:

Use the calculator you're most comfortable with.

Your child should be able to operate their ACT calculator as smoothly and instinctively as they text on their phone. They shouldn't have to hunt for the sine button, fumble through menus to find the statistics functions, or wonder how to change between radian and degree mode.

Calculator fluency — the ability to use the device quickly and without conscious thought — is a legitimate test-day advantage. Every second spent navigating menus or figuring out how to enter an expression is a second not spent solving the problem.

This means:

• •If your child has been using a TI-84 in school all year, bring the TI-84 to the ACT. Don't switch to a fancier model two weeks before the test.
• •If your child has been using a Casio graphing calculator and is comfortable with it, bring the Casio (as long as it's an approved model). There's no inherent advantage to the TI-84 over a Casio — the advantage is in familiarity.
• •If your child borrows a calculator from a friend or sibling, make sure they practice with it extensively before test day. An unfamiliar calculator is worse than no calculator at all, because it creates friction and frustration at the worst possible time.

If You're Switching Calculators, Practice Early

Sometimes a switch is unavoidable — your child has been using a TI-89 (CAS, not allowed) in school and needs to transition to a TI-84 for the ACT. That's fine, but the transition needs to happen weeks before the test, not days.

We recommend at least 2–3 weeks of daily practice with the new calculator. Use it for homework. Use it during practice tests. Use it until it feels natural. The goal is for the calculator to be invisible on test day — a tool that works seamlessly in the background, not something that demands attention and creates stress.

Calculator Strategy: When to Use It and When Not To

Having an approved, familiar calculator is step one. Using it strategically is step two.

Don't Use It for Everything

One of the biggest mistakes students make is reaching for the calculator on every single problem. Many ACT Math questions — especially in the first half of the section — are designed to be solved quickly with mental math or simple pencil-and-paper work. Typing a simple arithmetic problem into a calculator actually takes longer than doing it in your head.

Reaching for the calculator should be a conscious decision, not a reflex. Use it when:

• •The arithmetic is complex (multi-step calculations, large numbers, decimals)
• •You need to graph a function to visualize a problem
• •You're checking your work on a problem you've already solved by hand
• •Trigonometric calculations are involved (sine, cosine, tangent values)

Skip it when:

• •The problem involves simple addition, subtraction, or multiplication
• •You can estimate the answer and eliminate choices
• •The problem is testing a concept, not a calculation (many ACT questions are)

Know Your Calculator's Key Functions

Before test day, make sure your child can quickly execute these functions on their specific calculator:

• •Basic operations: Obviously — but also order of operations with parentheses
• •Fractions and decimals: Converting between the two
• •Exponents and roots: Square roots, cube roots, raising to a power
• •Trigonometric functions: Sine, cosine, tangent — and switching between degree and radian mode
• •Graphing: Entering a function and finding key points (intersections, zeros, max/min)
• •Statistics: Mean, standard deviation (less common but occasionally useful)

If your child can do all of the above in under 5 seconds each, they're in good shape.

The Digital ACT: Built-In Calculator

As the ACT continues its transition toward digital testing, it's worth noting that the digital ACT includes a built-in calculator for the Math section — specifically, a Desmos graphing calculator integrated into the testing interface.

This is a significant development. Students taking the digital ACT have the option of using either their own physical calculator or the built-in Desmos calculator (or both).

If your child is taking the digital ACT, they should:

1. 1.Practice with Desmos ahead of time. It's free at desmos.com. Get familiar with the interface, the way it handles graphing, and its limitations.
2. 2.Still bring their own calculator. Having a physical backup is smart. Some students prefer the tactile feel of a physical calculator, and switching between the screen-based Desmos and a physical device gives them flexibility.
3. 3.Know which tool is faster for which task. Desmos is excellent for graphing and visualizing functions. A physical TI-84 might be faster for quick calculations. The best strategy often involves using both.

Test-Day Calculator Checklist

Here's a quick checklist to tape to the fridge the week before the ACT:

• •[ ] Calculator is an approved model (no CAS, no QWERTY keyboard, no internet connectivity)
• •[ ] Fresh batteries installed (or fully charged if using the TI-84 Plus CE)
• •[ ] Backup batteries packed (for non-rechargeable models)
• •[ ] Calculator is in the correct mode (degree mode for trig, normal notation)
• •[ ] Memory cleared (some proctors may ask students to clear calculator memory before the test — know how to do this)
• •[ ] Student has practiced with this exact calculator for at least 2 weeks

Don't Let a Calculator Mistake Cost Points

The ACT calculator policy is one of those things that's simple to get right but painful to get wrong. A student who shows up with a banned calculator or an unfamiliar device is starting the Math section at a disadvantage — and on a test where every point matters for scholarships and admissions, that's a disadvantage no family can afford.

Get the right calculator. Practice with it. Bring fresh batteries. And then forget about it — because on test day, your child's focus should be on the questions, not the equipment.

For more test-day preparation tips and ACT strategies, explore our ScoreJump ACT Prep Course or check out our FAQ page for answers to the most common questions we hear from families. And if you want personalized guidance on your child's ACT prep plan, contact us anytime — we're here to help.