ACT Calculator Policy 2026: Allowed and Banned Calculators

The ACT calculator policy allows any four-function, scientific, or graphing calculator on the Math test, as long as it is not on ACT's prohibited list. The banned calculators are the ones with a built-in computer algebra system (CAS): every TI-89 and TI-92, the TI-Nspire CAS, the HP Prime, and a handful of HP and Casio models listed below. A TI-84 Plus or a non-CAS TI-Nspire is fine.

This page follows ACT's current policy document, which is marked as updated June 1, 2026, and the matching calculator policy page on act.org. It applies to the October 17 and December 12, 2026 national test dates, for both paper and online testing. Check your exact model against the tables before you pack your bag.

What Calculators Are Allowed on the ACT?

ACT does not publish a list of approved models. The rule works the other way around: every four-function, scientific, or graphing calculator is permitted unless it appears on the prohibited list or has a banned feature. Some permitted calculators need a small modification first, which is covered further down.

Two things surprise students every year. First, you have to bring your own calculator for the paper test. ACT states that testing staff do not provide them. Second, you may not share a calculator with another student during the test.

ACT also notes that every Math question can be solved without a calculator. That is useful to know if your batteries die, but 45 questions in 50 minutes is tight, so a familiar calculator is still worth bringing. If you want to see which questions reward calculator use, our ACT Math tips and the ACT Math formulas cheat sheet are the place to start.

Prohibited Calculators on the ACT (Full List)

The core of the ACT calculator policy is the CAS rule. Calculators with built-in or downloaded computer algebra system functionality are prohibited. ACT names these models specifically:

Watch the lookalikes. The HP 48GII is banned while the older HP 48G is permitted once its infrared port is covered. The TI-Nspire CAS is banned while the standard TI-Nspire is permitted. The word "CAS" printed on the case is the fastest check, but the TI-89 and HP Prime have CAS without saying so in the name.

ACT also prohibits these device types, whatever the brand:

What Is CAS, and Why Does ACT Ban It?

A computer algebra system does algebra symbolically. According to ACT's CAS calculator FAQ, a CAS typically solves equations algebraically, simplifies expressions, performs algebraic manipulations, and does exact arithmetic instead of rounding. Type in an equation and a CAS calculator hands back the solved form. Since the ACT Math test is partly measuring whether you can do that analysis yourself, ACT keeps the tool out of the room.

The rule covers software as well as hardware, and this is where owners of permitted calculators get caught:

• Programs and apps with CAS functionality must be removed. ACT treats an app as a kind of program, so both count.
• All documents must be removed, whatever they are for.
• Disabling is not enough. ACT's FAQ says that putting the calculator into Press-to-Test mode does not satisfy the policy. The programs have to be deleted.
• Simple math programs can stay. Single-purpose programs, such as one that finds numeric solutions to a quadratic, are allowed if they are written in the calculator's own language, run no longer than 25 logical lines of code, and do not call another program.

If you are not sure whether a program or app crosses the line, ACT's own recommendation is to remove it before test day. Back your programs up to a computer first so you can restore them afterward.

Calculators That Need a Modification First

Some calculators are permitted only after you change something. Do this at home, not at the check-in table.

ACT puts the responsibility on you, not the proctor. You are expected to know whether your calculator is permitted, to make sure it works, and to bring fresh batteries. A backup calculator or spare batteries are allowed if you want them.

The Online ACT and the Built-In Desmos Calculator

If you take the ACT online at a test center, a Desmos graphing calculator is built into the testing platform and available during the Math section. You do not have to use it. ACT's policy says online testers may still bring and use their own permitted handheld calculator instead of the on-screen one.

If you plan to rely on Desmos, practice with it before test day. Clicking through an on-screen calculator is slower than pressing keys you already know, and the Math section gives you a little over a minute per question. ACT links free video tutorials for both Desmos and handheld TI calculators from its calculator policy page. Students who learned Desmos for the digital SAT have a head start, and our Desmos practice guide covers the graphing moves that transfer.

Which ACT Sections Allow a Calculator?

Only one. ACT's policy says calculators may be used only on the mathematics test. That means no calculator on English, Reading, the optional Science section, or the optional Writing test.

Science is the one that trips people up. The section is full of graphs and data tables, but any arithmetic has to be done by hand or by estimating, because your calculator has to stay put away. If you added Science to your registration, our ACT Science guide shows how to handle the numbers without one.

What Happens If You Bring a Prohibited Calculator?

The policy document is blunt about this: examinees who do not follow it may be dismissed and have their tests voided for prohibited behavior. Testing staff are instructed to monitor the room during the Math test and to dismiss anyone found using a prohibited calculator. A dismissed test is not scored, and ACT's fees are generally nonrefundable.

In practice the risk comes in three forms: a banned model (the TI-89 is the classic), a permitted model with CAS programs still loaded, and a calculator left out on the desk during a section where it is not allowed. If you discover on test morning that your calculator is on the banned list, leave it in your bag and work the Math test by hand or, if you are testing online, with Desmos. Every question is solvable without one.

ACT vs. SAT Calculator Policy

The two tests now land in nearly the same place on CAS. College Board's SAT calculator policy also bans calculators with CAS functionality, and its named examples overlap heavily with ACT's list. The practical differences are about who gets Desmos and when the calculator can be out.

If you are taking both tests this fall, one non-CAS graphing calculator with its programs cleaned up works for each. Our SAT calculator policy guide has the College Board side in full.

Once the calculator question is settled, the rest of test day is simple: confirm your reporting time in our guide to what time the ACT starts, and check the ACT test dates page if you still need to register for December 12. The regular deadline for that date is November 6.

Frequently Asked Questions About the ACT Calculator Policy

Can you use a TI-84 on the ACT?

Yes. The TI-84 Plus family are graphing calculators without a computer algebra system, and they are not on ACT's prohibited list. You still need to remove any stored documents and any programs or apps with CAS functionality before test day.

Is the TI-Nspire allowed on the ACT?

The standard TI-Nspire (non-CAS) is permitted, and ACT says so by name. The TI-Nspire CAS is prohibited. Check the label on your calculator, because the two look almost identical.

Is the TI-89 allowed on the ACT?

No. Every model number that begins with TI-89 or TI-92 is prohibited because those calculators have a built-in computer algebra system.

Is Desmos allowed on the ACT?

Only the version built into the online ACT. Students who test online get an on-screen Desmos graphing calculator during the Math section. On the paper ACT there is no Desmos, and you cannot use Desmos on a phone, tablet, or laptop of your own.

Can you use a calculator on ACT Science?

No. ACT allows calculators only on the mathematics test, so plan to handle any Science arithmetic by estimating or with quick mental math.

Do I have to clear my calculator's memory before the ACT?

You have to remove all documents and any programs or apps with CAS functionality. ACT does not require a full memory wipe, and short single-purpose programs written in the calculator's own language are allowed. Press-to-Test mode by itself does not meet the policy.

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