Casio ClassWiz CW fx-991CW Scientific Calculator vs Texas Instruments TI-84 Evo
Buy the Casio ClassWiz fx-991CW for high school and college math, science and engineering courses where a graphing calculator is not required. It is lighter, cheaper to run and has a clearer input display. Buy the TI-84 Evo if your course, exam board or teacher requires a TI-84, or you need color graphing and a rechargeable battery. The Evo's lowest recent price was $69.99 on November 2, 2026, against a high of $76.99 on November 1, 2026; no Casio price was given.
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Casio ClassWiz CW fx-991CW Scientific Calculator
Choose the Casio ClassWiz fx-991CW if you need a fast, light scientific calculator for exams, with a four-tone screen that shows exactly what you are entering.
- 540 functions in a 95 g body
- Four-tone screen shows which part is being entered
- OK and Back keys plus a streamlined layout
- Runs on solar with an LR44 backup
- MathBox learning feature and ClassPad.net link
- No graphing and no color screen
- Only 9 variable slots
- Button battery needs replacing about every 2 years
What separates them
| Casio ClassWiz CW fx-991CW Scientific Calculator | Texas Instruments TI-84 Evo | |
|---|---|---|
| Type | Scientific calculator, 540 functions | Graphing calculator with 15 graph colors |
| Power | Solar cell plus LR44 button battery, about 2 years at 1 hour a day | Rechargeable TI battery, charged over USB |
| Display | 4-gradation LCD with grey tone marking the active entry | 2.8-inch 320x240 color screen at 140 DPI |
| Weight and size | 95 g, 10.7 x 77 x 162 mm | Handheld with impact-resistant slide case |
| Memory | 9 variable storage slots | 3.5 MB flash, 21 KB RAM, lists to 999 elements, 10 matrices up to 20x20 |
| Computer link | ClassPad.net connection for ICT classes | USB port for computer connectivity |
| Exam fit | Built for general math, science and engineering courses |
Price history
- Casio ClassWiz CW fx-991CW Scientific Calculator: lowest $25.99 on Nov 1.
- Texas Instruments TI-84 Evo: lowest $69.99 on Nov 2 at PayMore Cary.
Prices at every store
Casio ClassWiz CW fx-991CW Scientific Calculator
- TeciSoftCheck price at TeciSoft
- WalmartCheck price at Walmart
Texas Instruments TI-84 Evo
- AmazonCheck price at Amazon
- Campus Bookstore on Dickson StreetCheck price at Campus Bookstore on Dickson Street
- PayMore CaryCheck price at PayMore Cary
Specs compared
| Spec | Casio ClassWiz CW fx-991CW Scientific Calculator | Texas Instruments TI-84 Evo |
|---|---|---|
| Color | Gray | — |
| Power requirements | Built-in solar cell; button battery LR44 × 1 | — |
| Battery life | 2 years (based on one hour of operation per day) | — |
| Operating temperature | 0°C to 40°C (32°F to 104°F) | — |
| Dimensions | 10.7 (H) × 77 (W) × 162 (D) mm | — |
| Dimensions (imperial) | 7/16” (H) × 3 1/16” (W) × 6 3/8” (D) | — |
| Weight | 95 g (3.4 oz) including the battery | — |
| Display type | quadruple graded LCD display | — |
| Scientific constants | 47 | — |
| Measurement conversions |
What reviewers say
Casio ClassWiz CW fx-991CW Scientific Calculator
Owners and reviewers generally rate the fx-991CW as a capable, well-built scientific calculator, but many long-time ClassWiz users say the new menu system takes getting used to compared with the fx-991EX. Teachers like the clearer display for showing entry order.
- Clear 4-gradation screen that highlights the active entry
- Fast, accurate calculation across functions
- Good key feel and sturdy build
- Solar power with battery backup
- Menu-driven layout is slower than the fx-991EX's direct keys
- Some functions take more button presses than before
- Display is small and not backlit
Texas Instruments TI-84 Evo
Owners of the TI-84 family generally praise the color display and the rechargeable battery, and many say the interface is easy to pick up. Complaints tend to focus on the limited RAM and the price relative to older TI-84 models.
Questions and answers
- Which is better for high school algebra and physics?
- The Casio fx-991CW covers both well and is lighter and simpler to use. Pick the TI-84 Evo only if your teacher or exam requires a graphing calculator.
- Which lasts longer?
- The TI-84 Evo runs on a rechargeable battery you top up over USB. The Casio runs on solar with an LR44 backup rated about 2 years at one hour of use a day.
- Is the TI-84 Evo worth the extra money?
- Yes if you need graphing, color plots or a required TI-84. If you only need scientific functions, the Casio does the job for less.
- Can the Casio graph?
- No. The fx-991CW is a scientific calculator with 540 functions, not a graphing calculator.
- Which is allowed in exams?
- Rules vary by exam board. The Casio is a standard scientific model; the TI-84 Evo is allowed only where graphing calculators are permitted. Check your board's list before buying.
- Which is easier to carry?
- The Casio at 95 g and 162 mm long slips into a pocket. The TI-84 Evo is larger and comes with a slide case.
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