ACT Math Calculator Tips

Many students assume that having a calculator in the ACT Math section will automatically make difficult questions easier. In practice, this assumption often slows students down. Over-reliance on the calculator, or inefficient use of its functions, can cost valuable time. The calculator is only a tool. Knowing when not to use it is just as important as knowing how to use it.

ACT Calculator Policy

Calculators are allowed only in the Mathematics section (including ACT WorkKeys Applied Math). All math questions on the ACT can be solved without a calculator, but using an approved device strategically can improve pacing and accuracy.

Testing centers do not provide calculators, and examinees are strictly prohibited from sharing calculators during the test. Bringing an unapproved device will lead to dismissal from the exam and cancelled scores.

Students should keep in mind:

1. Approved vs. Prohibited Devices

You may bring any 4-function, scientific, or graphing calculator, provided it does not have built-in Computer Algebra System (CAS) capabilities or restricted communication features.

A. Prohibited Texas Instruments Models:

• All model numbers beginning with TI-89 or TI-92
• TI-Nspire CAS (Note: TI-Nspire non-CAS versions are permitted)

B. Prohibited Hewlett-Packard (HP) Models: HP Prime, HP 48GII, and all HP 40G, HP 49G, or HP 50G series

C. Prohibited Casio Models:

• fx-CP400 (ClassPad 400), ClassPad 300 / ClassPad m330
• Algebra fx 2.0 and all CFX-9970G models 

D. Other Prohibited Devices:

• Laptops, tablets, cell phones, PDAs, and wearable smart devices
• Calculators with QWERTY keyboards (standard computer key layout)
• Electronic writing pads or pen-input devices (Exception: The Sharp EL-9600 is permitted)

2. Required Modifications for Test Day

If your calculator has certain features, you must modify it before entering the testing room:

• Programs & Documents: Remove all stored documents and any installed programs with CAS functionality.
• Infrared Data Ports: Completely cover the infrared port with heavy opaque material (such as duct tape).
• Sound & Paper Tape: Turn off all sound features and remove any paper printing tape.
• Power Source: Calculators must run on battery power; power cords and electrical plug-ins are prohibited.

3. Note for Digital ACT Test-Takers

Students taking the Digital ACT (online) have access to an interactive Desmos graphing calculator built directly into the testing platform during the Math section. You may still bring your own approved handheld calculator if you prefer physical buttons.

Carrying an unapproved calculator can lead to unnecessary stress and wasted time at the test centre.

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Learn the Calculator Before the Exam

A common mistake is purchasing a new or advanced calculator just before the test without sufficient practice. This often leads to confusion during the exam.

Students should be comfortable performing the following:

• Fraction and decimal conversions
• Square roots and exponents
• Basic arithmetic efficiently
• Memory functions for multi-step calculations
• Evaluating expressions
• Basic graphing features (if using a graphing calculator)

The goal is to make routine operations automatic so that no time is lost during the test.

Know When to Use the Calculator

Not every question requires a calculator. In many cases, mental math or simple written steps are faster.

High-performing students typically avoid using the calculator for:

• Basic arithmetic
• Simple percentages
• Straightforward algebra

The calculator is most useful for:

• Long or messy decimal calculations
• Complicated fractions
• Exponents and powers
• Trigonometric values (ensure degree mode is selected)
• Verifying answers quickly

Using the calculator selectively improves both speed and accuracy.

Use Built-in Functions Efficiently

Understanding built-in functions can reduce errors and save time:

• Parentheses: Ensures correct order of operations
• Fraction/decimal conversion: Helps compare answer choices quickly
• Memory functions: Useful for multi-step calculations
• Table/graph features: Can help check patterns or equations (optional, not essential)

Graphing features can be helpful, but the ACT is designed so that most questions can be solved faster without relying on them.

Use the Same Calculator for Practice and Test Day

Switching calculators close to the test can reduce efficiency. Practice with the same calculator you plan to use on test day. This builds familiarity, speed, and confidence.

Check the Calculator Before the Exam

Basic checks before the test can prevent avoidable issues:

• Ensure battery is functioning or fully charged
• Confirm degree mode is selected for trigonometry
• Clear any unnecessary stored data
• Verify that all keys and functions are working properly

You will not be provided a calculator during the ACT, so preparation is essential.