TI-BASIC Programming on the TI-84: Write Your First Program
Ready to write code on your calculator? This TI-BASIC programming guide takes you from a blank program to a working quadratic solver: create programs in the PRGM menu, and use Disp, Input, If/Then, and loops.
Quick answer: Press PRGM, arrow to NEW, choose 1:Create New, and type a program name. Add commands from the PRGM → CTL menu (If, Then, For() and PRGM → I/O menu (Disp, Input, Prompt). Press 2ND + MODE to save, then run it from PRGM → EXEC. Start with the quadratic solver example below.
Creating your first program
- Press PRGM and arrow right to NEW.
- Choose 1:Create New and press ENTER.
- Type a name up to 8 characters — it must start with a letter (ALPHA lock turns on automatically here). Press ENTER.
You are now in the program editor with a blank PROGRAM:NAME screen. Every line of a TI-BASIC program starts with a colon — the calculator inserts it for you automatically at the start of each new line.
The essential commands
You never type commands letter by letter — you pick them from menus, which guarantees correct syntax. Mastering these menus is the fastest way to learn TI-BASIC programming.
- PRGM → CTL (control): If, Then, Else, End, For(, While(, Pause, Lbl, Goto.
- PRGM → I/O (input/output): Disp, Input, Prompt, ClrHome.
Prompt asks the user for values and stores them (Prompt A,B), Disp shows results, and the arrow → (STO→ key) stores values into variables (5→X).
Your first program: a quadratic solver
Create a new program named QUAD and enter these lines exactly (pick each command from its menu):
- :ClrHome — clears the screen.
- :Prompt A,B,C — asks for the three coefficients.
- :B²−4AC→D — computes the discriminant into D.
- :If D<0 — then :Then
- :Disp “NO REAL ROOTS” — then :Else
- :Disp (−B+√(D))/(2A)
- :Disp (−B−√(D))/(2A)
- :End
Press 2ND + MODE (QUIT) to save and exit. Run it: PRGM → EXEC → choose QUAD → ENTER twice. Enter A=1, B=−3, C=2 — the program displays 2 and 1, the two roots.
Loops: For( and While(
- :For(X,1,10) … :Disp X² … :End — displays the squares 1 through 100.
- While( repeats while a condition stays true — ideal for guessing games.
Inside a loop, Pause freezes the screen until you press ENTER.
Debugging checklist
- Count your Ends. Every Then, For(, and While( needs one. Missing End → ERR:SYNTAX.
- Check the TEST operators. The = inside an If must come from 2ND + MATH (TEST), not the ENTER key.
- Watch your quotes. Every opening “ in a Disp needs a closing one.
- Test pieces on the home screen. Any single expression can be typed at the home screen first.
Running, editing, and deleting programs
- Run: PRGM → EXEC → choose the program → ENTER → ENTER.
- Edit: PRGM → EDIT → choose the program.
- Delete: 2ND + + (MEM) → 2:Mem Mgmt/Del → 7:Prgm → highlight → DEL.
For the official command reference, see Texas Instruments, or try every command on our free TI-84 calculator.
TI-BASIC programming: frequently asked questions
Why do I get ERR:SYNTAX when I run my program?
Almost always a missing End, a misplaced parenthesis, or a command typed letter-by-letter instead of picked from the menu.
How do I stop a program that is stuck in a loop?
Press ON and choose 2:Quit.
Will my programs survive a RAM reset?
No — a RAM clear wipes them. Archive important programs or back them up with TI Connect CE first.
Are TI-BASIC programs allowed on exams?
Programs you wrote yourself are generally fine on the SAT/ACT/AP, but some teachers require cleared memories. When in doubt, ask before test day.
Can I share my programs with a friend?
Yes — link two calculators with a USB cable and use 2ND + X,T,θ,n (LINK) to send programs. It’s also how classrooms distribute TI-BASIC programming examples.
How do I back up my TI-BASIC programs?
Archive important programs to Flash memory (2ND + MEM) or transfer them to a computer with TI Connect CE. Losing hours of TI-BASIC programming work to a RAM clear is painful.
How do you program a TI-84?
You write programs in TI-BASIC in the calculator’s program editor — never by typing commands letter by letter, but by picking them from the PRGM → CTL and PRGM → I/O menus, which guarantees correct syntax. Press PRGM, create a new program, add your commands, press 2ND + MODE to save, and run it from PRGM → EXEC. Start with the quadratic solver example in this guide.
How do you create a new program on a TI-84?
Press PRGM and arrow right to NEW. Choose 1:Create New and press ENTER. Type a name up to 8 characters — it must start with a letter (ALPHA lock turns on automatically here) — then press ENTER. You are now in the program editor, and the calculator inserts the starting colon for every line automatically.
What is TI-BASIC?
TI-BASIC is the language you use to write programs on the TI-84. You write it in the calculator’s program editor using commands picked from the PRGM menus — such as If, Then, For(, Disp, Input and Prompt — and every line starts with a colon, which the calculator inserts automatically.
How do you run a program on a TI-84?
Press 2ND + MODE (QUIT) to save and exit the editor, then press PRGM, arrow to EXEC, choose your program and press ENTER twice. For the quadratic solver example, that is PRGM → EXEC → choose QUAD → ENTER twice.
