ACT Calculator Policy: Is a TI-84 Allowed on the Maths Test?

Is a TI-84 allowed on the ACT? Yes, but only for part of the sitting. Under the ACT calculator policy a permitted calculator — and the TI-84 Plus and TI-84 Plus CE are permitted — may be used on the mathematics test only. It is not allowed on the other tests.

The wording is precise about this. The restriction is not about the model of calculator being dangerous; it is about which test you are taking. During the mathematics test the TI-84 is a permitted tool; during the other tests it needs to be off the desk.

That makes the ACT slightly different from the SAT, where some form of calculator is available across the whole mathematics section. On the ACT the practical skill is managing the boundaries of the mathematics test rather than choosing between two tools.

Where the ACT allows a calculator

The permitted calculator is allowed on the mathematics test only. For every other test in the sitting, the calculator must stay out of use. That single sentence is the rule that causes the most confusion, because students read “calculator allowed” and assume it applies to the whole exam.

So the ACT position is narrower than the digital SAT’s. You should plan not only for the mathematics test but also for the tests where you will work without a calculator. If your preparation assumes a handheld at every stage, adjust it: rehearse those items the way you will actually sit them.

Is a TI-84 permitted on the ACT?

Yes. The TI-84 Plus and TI-84 Plus CE fall on the permitted side of the ACT’s rules because they are numeric graphing calculators without the features ACT excludes. They evaluate expressions and draw graphs; they do not carry the prohibited capabilities.

Because the calculator is allowed only in the one test, it helps to be fluent rather than experimental. The operations you use most — evaluating an expression, solving an equation, reading a graph, or checking a summary statistic — should be so practised that they take seconds, not minutes. A calculator you are still learning is slower than one you know.

If you keep meeting a value error, the message is often about the input rather than the calculator; see our ERR: DOMAIN guide for the usual causes.

What the ACT prohibits

ACT excludes calculators on the basis of features. The prohibited list includes:

• A computer algebra system (CAS). A CAS performs symbolic manipulation, working with algebraic expressions as objects rather than merely evaluating them to numbers. ACT treats this capability as not permitted.
• A QWERTY keyboard. A full letter layout is excluded, just as it is on the SAT and elsewhere. A standard calculator keypad does not trigger this restriction.

Recording or communication functions sit outside the testing room entirely: phones and similar devices are not permitted, so a dedicated handheld is the safe choice. The TI-84 Plus and the CE have none of the excluded features, which keeps both models on the permitted side.

If you are choosing a calculator, check the exact model against ACT’s list rather than assuming that every graphing calculator qualifies. TI sells several graphing models, and only the ones without a CAS meet the rule.

At the start of the test

Because the calculator is permitted for one test and not the others, the start of the sitting is the moment to get the logistics right.

• Listen for the invigilator’s instructions. They will say when the calculator may be used. Do not assume; follow what you are told in the room.
• Keep it put away until then. During the tests where a calculator is not permitted, it should be off the desk and out of reach rather than sitting in front of you.
• Get it out promptly when the mathematics test begins. A minute spent finding the unit is a minute of mathematics time lost.
• Check the mode before you start. Confirm the settings your preparation assumed, then leave the menu with 2nd MODE.

One practical note about accessories: a spare set of batteries or a charged cable belongs in your bag, because you cannot swap in a different calculator mid-test. Our TI-84 accessories guide covers the small items worth packing.

Check the current ACT policy

ACT updates its policy and its test-day materials from time to time, so the version you read last year is not guaranteed to be the version in force for your sitting. The safe routine is simple: open ACT’s official site, read the permitted-calculator list against your exact model, and confirm the details with your school before the test.

The rules here are also summarised alongside the other boards on our overview of TI-84 exam rules, and the neighbouring SAT calculator policy page explains how the digital SAT differs. Where any summary and the official ACT wording disagree, the official ACT wording wins.