Programs are what transform the TI-84 from a capable calculator into a custom problem-solving machine. By storing formulas, building interactive solvers, and automating repetitive calculations, programs multiply the calculator's usefulness far beyond its built-in features. Whether you write your own programs or download pre-made ones from the rich community of TI calculator developers, this guide covers everything you need to know.
Introduction
Programs are what transform the TI-84 from a capable calculator into a custom problem-solving machine. By storing formulas, building interactive solvers, and automating repetitive calculations, programs multiply the calculator's usefulness far beyond its built-in features. Whether you write your own programs or download pre-made ones from the rich community of TI calculator developers, this guide covers everything you need to know.
The TI-84's programming language supports input and output commands, conditional logic, loops, and all mathematical operations available on the calculator itself. This is sufficient to build programs that solve quadratic equations, apply physical formulas, perform statistical calculations with custom interfaces, or implement any algorithm you can describe in terms of arithmetic and logic.
A crucial practical point: programs are allowed on most major standardized exams including the SAT, ACT, and all AP exams. The College Board explicitly permits programs for mathematical calculations stored on approved calculators. This makes programming the TI-84 not just an interesting technical skill but a legitimate exam preparation strategy.
Writing Your First Program: Quadratic Formula
Press PRGM → NEW → Create New. Type a program name up to 8 characters using letters (no spaces or special characters). Try QUADFORM. Press ENTER to open the program editor. You will see the program name as the first line and a cursor ready for commands.
Enter commands using the PRGM menu while in the program editor. Press PRGM → I/O for Input/Output commands including Prompt (asks the user for a value), Disp (displays output), and Input (prompts with a custom message). Press PRGM → CTL for control flow commands including If, Then, Else, End, For, While, and Goto.
A complete quadratic formula program: The first line reads Prompt A,B,C to collect the three coefficients. The second line computes the discriminant and stores it: B^2-4*A*C → D. Then If D < 0 followed by Disp "NO REAL ROOTS" handles negative discriminant cases. If D ≥ 0, display the two roots using (-B+sqrt(D))/(2*A) and (-B-sqrt(D))/(2*A). Press 2ND+MODE to save and exit. Run with PRGM → EXEC → QUADFORM, entering coefficients when prompted.
Writing a Distance Formula Program
Create a second program named DISTANCE. The program collects two coordinate pairs (X1, Y1, X2, Y2), computes the Euclidean distance, and displays the result. The prompt line should ask for X, Y, A, B representing the four coordinates. The computation line calculates sqrt((A-X)^2+(B-Y)^2) and stores the result in D. Display "DISTANCE=" followed by D.
This program structure — prompt for inputs, perform computation, display results — is the template for approximately 90% of useful student programs. Once you understand this pattern, you can build programs for any formula you use repeatedly: law of cosines, compound interest, kinematics equations, statistical measures, or unit conversions.
More sophisticated programs can use loops to iterate calculations, conditional branches to handle different cases, and multiple Disp commands to show step-by-step working. For example, a triangle solver program could detect whether the input describes a valid triangle, compute all sides and angles using the laws of sines and cosines, and display each result with a labeled description.
How to Download and Install Programs
Thousands of pre-written TI-84 programs are freely available from community sites including ticalc.org, Cemetech.net, and Texas Instruments' own education portal at education.ti.com. These programs are distributed as .8xp files — the native TI-84 program file format.
To install programs: First, download and install TI Connect CE (free from education.ti.com) on your computer. Connect your TI-84 to your computer using the USB cable that came with the calculator (TI-84 Plus CE uses a mini-USB; older models may use a different connector). Open TI Connect CE and navigate to the Calculator Explorer view. Drag and drop .8xp program files from your computer to the calculator icon in TI Connect CE. The programs transfer immediately and appear in your PRGM menu.
Programs can also be transferred directly between two TI-84 calculators using the unit-to-unit link cable that plugs into the small port on the bottom of each device. On the sending calculator, press 2ND+X,T,theta,n (LINK) → Send → select All or specific programs. On the receiving calculator, press LINK → Receive. The program transfers over the cable in seconds.
Most Useful Pre-Written Programs for Students
Quadratic formula solvers handle all quadratics including complex roots, displaying both roots with full decimal precision. Polynomial root finders extend this to higher-degree polynomials, finding all roots including complex ones up to degree 5 or higher. These are valuable for any algebra or pre-calculus course.
Triangle solvers implement the law of sines and law of cosines for any triangle configuration (SSS, SAS, ASA, AAS, HL). They detect ambiguous cases in the law of sines and display all possible solutions. Physics and chemistry formula programs store the most commonly used formulas (kinematics, Coulomb's law, gas laws, molar mass) and prompt for inputs, computing results instantly.
AP Statistics programs are particularly valuable: t-test calculators that show all intermediate steps, chi-squared test programs, normal distribution probability calculators with work shown, and regression diagnostics. Riemann sum programs compute left, right, midpoint, and trapezoidal approximations with the number of subdivisions as an input parameter — essential for AP Calculus numerical integration exercises.
Further Reading & Sources
How Programs Work on the TI-84
The TI-84 includes a built-in programming language (TI-BASIC) that lets you store sequences of calculator commands and execute them with a single key press. Programs are stored in RAM and survive battery replacement (though they are deleted if you reset the calculator). You can write programs directly on the device via PRGM → NEW, or transfer them from a computer using TI Connect CE software and a mini-USB cable.
On our free online TI-84, the programming environment works the same way — access it via the PRGM key. You can write, store, and run programs directly in the browser.
The Quadratic Formula Program
The single most popular TI-84 program stores the quadratic formula and automatically outputs both roots for ax²+bx+c=0. When run, it prompts you for A, B, and C, then outputs X1 and X2 (including complex roots if the discriminant is negative). This saves 30–45 seconds per problem on exams. The program is about 20 lines of TI-BASIC and takes 5 minutes to enter. On exam day, run it to verify your hand-calculated roots instantly.
Distance and Midpoint Formula
A simple program that prompts for (X1,Y1) and (X2,Y2) and outputs the distance d=√((X2−X1)²+(Y2−Y1)²) and midpoint ((X1+X2)/2,(Y1+Y2)/2). Essential for Geometry and Pre-Calculus courses. Takes under 2 minutes to enter and eliminates arithmetic errors in multi-step distance problems.
Law of Sines and Law of Cosines Solver
Trigonometry students benefit from a triangle solver program that uses the Law of Sines (a/sinA = b/sinB = c/sinC) or Law of Cosines (c²=a²+b²−2ab·cosC) to find missing sides and angles. Input the known values and the program determines which law applies and outputs all missing measurements. This is particularly useful for ambiguous case (SSA) problems where two triangles may exist.
Slope-Intercept and Point-Slope Converter
Enter two points or a point and slope, and the program outputs the equation in both y=mx+b form and standard form Ax+By=C. Includes the slope calculation and automatically handles vertical lines (undefined slope). This is one of the most used algebra programs for students in Algebra 1 through Pre-Calculus.
Are Programs Allowed on Exams?
This is critical: exam policies on programs vary. The SAT and ACT permit programs on the TI-84 — there are no restrictions on stored programs. The AP Calculus and AP Statistics exams permit programs. However, some teachers and schools require calculators to be cleared before in-class tests. Always check your specific exam's policy. For the physical TI-84, you can press 2ND → MEM → 2:Mem Mgmt/Delete to manage what's stored. Our online tool does not persist data between sessions.
Where to Find TI-84 Programs
Beyond writing your own, you can download community-made programs from repositories like ticalc.org, the largest archive of TI calculator programs, and transfer them via TI Connect CE software. Many teachers and tutors also share programs directly. Always verify a downloaded program's code before running it on your calculator.