Quick verdict
- Still a capable CAS calculator for calculus, differential equations, and engineering.
- Cheap used. Often less than half the price of a new TI-84 Plus CE.
- Banned on the SAT and ACT because of its computer algebra system.
- Monochrome screen and AAA batteries feel dated next to modern calculators.
- Great value for college students whose courses and exams allow CAS.
Specs
| Spec | TI-89 Titanium |
|---|---|
| Released | June 2004 |
| Processor | Motorola 68000, ~12 MHz |
| Memory | ~188 KB user RAM, ~2.7 MB user flash |
| Display | Monochrome LCD, 160 × 100 |
| CAS | Yes |
| Power | 4 × AAA + backup coin cell |
| Connectivity | USB + link port |
| Exams | Allowed on AP Calculus; prohibited on the SAT and ACT |
| Used price | ~$30–$45 typical (median ~$40) |
What it is
The TI-89 Titanium replaced the original TI-89 in 2004. It was Texas Instruments' answer to a simple question: what if the calculator could do algebra, not just arithmetic?
Its computer algebra system (CAS) works with symbols, not just numbers. It can factor expressions, solve equations for a variable, take derivatives and integrals symbolically, and simplify messy results. For calculus and engineering students in the 2000s, it was the calculator.
Why people still want one
- Price. Across 232 used units sold on eBay from mid-2025 to October 2026, the middle half went for $30 to $45, with a median of about $40. That's real CAS power for less than half the price of a new TI-84.
- Capability. For calculus, differential equations, linear algebra, and circuit analysis, it still holds up.
- Durability. These were built well. Many 15- to 20-year-old units still work fine.
- Familiarity. Plenty of professors and engineers learned on one and still recommend it.
Exam restrictions: read this first
Because of its CAS, the TI-89 Titanium is prohibited on the SAT and the ACT. The SAT policy names it specifically, and it's one of the most common reasons students get a calculator rejected on test day.
It is allowed on AP Calculus exams. Some college courses also ban CAS calculators on exams, so check the syllabus.
Check the official rules before test day: the ACT calculator policy, the SAT calculator policy, and the AP calculator policies.
What feels dated
- The screen. A small monochrome LCD with no backlight. Graphs are readable but basic.
- Batteries. Four AAA batteries plus a backup coin cell. No rechargeable option.
- Speed. The processor is slow by modern standards. Complex symbolic work can take a few seconds.
- Interface. Powerful, but menu-heavy and less intuitive than newer designs.
Who should buy one
- College students in calculus-heavy or engineering courses that allow CAS.
- Anyone who wants symbolic math on a tight budget.
- Collectors of TI's classic lineup.
Who should skip it:
- High school students who will take the SAT or ACT.
- Anyone whose class requires a specific calculator.
- Students who'd benefit from a color screen and modern interface. Look at the TI-Nspire CX II CAS instead.
Our take
For a college engineering student on a budget, a used TI-89 Titanium is still one of the best deals in calculators. Around $40 buys real symbolic algebra.
For a high schooler, it's the wrong tool. It's banned on both the SAT and the ACT, and a TI-84 Plus CE will cause fewer headaches.
Depends on your exams
For a college engineering or math student who wants symbolic algebra on a budget, a used TI-89 Titanium is still a great deal. For a high school student who will take the SAT or ACT, it's the wrong calculator. Buy a TI-84 Plus CE or a non-CAS Nspire instead.
Where to buy
Prices change often. Check the current price before buying. Some links are affiliate links, which never change our verdicts.
FAQ
Why is the TI-89 Titanium banned on the ACT?
It has a computer algebra system (CAS), which can solve and simplify symbolic expressions. The ACT prohibits CAS calculators.
Can I use a TI-89 Titanium on the SAT?
No. The College Board's SAT calculator policy prohibits CAS calculators and names the TI-89 specifically. It is allowed on AP Calculus exams.
How much is a used TI-89 Titanium worth?
Most used units sell for about $30 to $45 on eBay, with a median around $40 (2025–2026 sold listings).
TI-89 Titanium or TI-Nspire CX II CAS?
The Nspire CX II CAS is faster, has a color screen, and is rechargeable. The TI-89 Titanium is much cheaper used.
