Casio ClassWiz CW fx-991CW Scientific Calculator vs Sharp EL531XT Scientific Calculator
Buy the Casio ClassWiz fx-991CW if you want a modern calculator for school or exams, with a clearer 4-tone display, 540 functions, and ClassPad.net linking. Choose the Sharp EL531XT if you want a cheap, light backup with N-base and fraction work. The Sharp's only recorded price is $14.99 as of November 1, 2026; no current price was given for the Casio, so compare it at checkout.
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Casio ClassWiz CW fx-991CW Scientific Calculator
Choose the Casio ClassWiz fx-991CW if you need a full-featured scientific calculator for class, with a 4-gradation display, MathBox practice, and ClassPad.net support.
- 540 functions cover most high-school and early college math
- 4-tone screen makes it easy to see what you are entering
- MathBox adds practice drills
- Links to ClassPad.net for ICT classes
- Solar plus battery power
- Bigger and heavier than the Sharp
- No current price was given, so cost is unclear
- More keys and menus to learn
What separates them
| Casio ClassWiz CW fx-991CW Scientific Calculator | Sharp EL531XT Scientific Calculator | |
|---|---|---|
| Display | 4-gradation LCD with a gray tone that shows which entry is active | 2-line LCD, 10 digits |
| Functions | 540 functions, 47 constants, 40 conversions | Trig, logs, exponents, fractions, statistics, N-base |
| Memory | Up to nine stored variables | Multi-line playback of past entries |
| Power | Solar cell plus LR44 battery, about 2 years at 1 hour per day | Solar powered |
| Size and weight | 162 x 77 x 10.7 mm, 95 g | 7.20 x 3.54 x 0.87 in, 0.1 lb |
| Learning features | MathBox practice and ClassPad.net linking | None listed |
| Warranty | Not stated in the listing | No written warranty |
Price history
- Casio ClassWiz CW fx-991CW Scientific Calculator: lowest $25.99 on Nov 1.
- Sharp EL531XT Scientific Calculator: lowest $14.99 on Nov 1 at eBay; $14.99 on Nov 2.
Prices at every store
Casio ClassWiz CW fx-991CW Scientific Calculator
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Sharp EL531XT Scientific Calculator
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Specs compared
| Spec | Casio ClassWiz CW fx-991CW Scientific Calculator | Sharp EL531XT Scientific Calculator |
|---|---|---|
| Color | Gray | White |
| Dimensions | 10.7 (H) × 77 (W) × 162 (D) mm | 7.20 x 3.54 x 0.87 in |
| Weight | 95 g (3.4 oz) including the battery | 0.1 lb |
| 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 (imperial) | 7/16” (H) × 3 1/16” (W) × 6 3/8” (D) | — |
| Display type | quadruple graded LCD display | — |
| Scientific constants | 47 | — |
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
Sharp EL531XT Scientific Calculator
The 20 ratings average 4.9 out of 5, and the written feedback is mostly about the buying experience rather than the calculator itself. Buyers describe the item as exactly as described, well packed and good value. One buyer received a unit that did not work, and the seller resolved it quickly.
Questions and answers
- Which is better for high-school math?
- The Casio. Its 540 functions, 4-tone display, and MathBox practice fit classroom work better than the Sharp's basic 10-digit, 2-line setup.
- Which is better for exams?
- Check your exam's approved list first. Both are non-programmable scientific calculators, but the Casio's extra functions and display make it the stronger study tool.
- Is the Sharp enough for statistics and fractions?
- Yes for basic work. It handles fractions, statistics, logs, and N-base conversions, but it has fewer functions and only 10 digits.
- Which lasts longer?
- The Casio runs on solar plus an LR44 battery rated for about 2 years at one hour a day. The Sharp is solar powered, but no battery life figure was given.
- Is the Casio worth the extra cost?
- If you will use the display, MathBox, and ClassPad.net, yes. If you just need quick arithmetic and N-base work, the $14.99 Sharp covers it.
- Which is easier to carry?
- The Sharp. It weighs 0.1 lb against the Casio's 95 g (3.4 oz) and is the smaller of the two.
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