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Casio fx-991CW Scientific Calculator vs Texas Instruments TI-36X Pro

Buy the TI-36X Pro if you want a proven, widely used scientific calculator for engineering and technical courses, with a four-line MultiView display and a long track record. Buy the Casio fx-991CW if you want Casio's newer ClassWiz layout, a clearer menu-driven interface and a high-resolution display. Both are solar-assisted with battery backup and handle fractions, roots and natural math display. The TI has far more owner feedback and a longer classroom history; the Casio is the more modern interface.

  • Choose the Casio fx-991CW if you want the newer ClassWiz interface with on-screen menus and a sharp high-resolution display.
  • Choose the TI-36X Pro if you want a battle-tested calculator with a four-line MultiView display and a huge base of owner experience.

Prices

  • Casio fx-991CW Scientific Calculator: $19.50 at eBay (last seen Nov 8)
  • Texas Instruments TI-36X Pro: $27.35 at Best Buy (last seen Nov 8)
  • Difference: the Casio fx-991CW Scientific Calculator is $7.85 cheaper than the Texas Instruments TI-36X Pro at the latest prices (Nov 8)
Casio
Casio fx-991CW Advanced Scientific Calculator

Casio fx-991CW Scientific Calculator

Casio fx-991CW Advanced Scientific Calculator

4.6(62 ratings)
$19.50at eBayObserved at 11:01 PM
See all prices and details
Visit eBay

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Pros
  • Modern ClassWiz menu interface
  • Sharp high-resolution display
  • Slim, light body
  • Natural textbook math entry
  • Solar with battery backup
Cons
  • Few owner ratings so far
  • Menu-driven flow takes getting used to
  • Less established in classrooms
Texas Instruments
Texas Instruments TI-36X Pro Scientific Calculator

Texas Instruments TI-36X Pro

Texas Instruments TI-36X Pro Scientific Calculator

4.7(1,000 ratings)
$27.35at Best BuyObserved at 9:55 PM
See all prices and details
Visit Best Buy
Pros
  • Four-line MultiView display
  • MathPrint textbook-style entry
  • Dedicated fraction/decimal toggle
  • Very large base of owner reviews
  • Long-standing standard for engineering courses
Cons
  • Older interface design
  • Bulkier body
  • Menu depth can slow simple calculations

What separates them

Casio fx-991CW Scientific CalculatorTexas Instruments TI-36X Pro
DisplayHigh-resolution LCD with menu-driven ClassWiz interfaceFour-line MultiView LCD with MathPrint
Math entryNatural textbook display with stacked fractions and rootsMathPrint shows expressions and stacked fractions as in textbooks
InterfaceIcon menu and function keys, fewer dedicated keysDirect function keys and scrollable entry history like a graphing calculator
PowerSolar with battery backupSolar with battery backup
Build and sizeSlim 6.4 x 3.0 x 0.4 in bodyLarger 7.25 in long body with a slide case
Owner feedback4.6 of 5 from 62 ratings4.7 of 5 from about 1,000 ratings
Exam familiarityNewer model, less classroom historyLong-standing standard in engineering courses
Fraction and decimal toggleSupported through the ClassWiz format keysDedicated toggle key converts fractions and roots to decimals and back

Price history

$25.99$20.25
Nov 1Nov 9
  • Casio fx-991CW Scientific Calculator: lowest $24.99 on Nov 9 at Office Depot.
  • Texas Instruments TI-36X Pro: lowest $20.25 on Nov 9 at EAI Education.

Prices at every store

Casio fx-991CW Scientific Calculator

  • TargetNew

    In stock

    $24.99+ $5.99 shippingObserved at 9:53 PM
    Visit Target
  • University of Alabama Supply StoreNew

    In stock

    $27.99+ $5.99 shippingObserved at 9:53 PM
    Visit University of Alabama Supply Store
  • eBayNew

    Availability unknownSold by tooloo99 (100% positive, 4,100 ratings)Returns: Set by the eBay seller; the eBay Money Back Guarantee covers an item that doesn't arrive or isn't as described.

    $19.50+ $6.12 shippingObserved at 11:01 PM
    Visit eBay
  • staples.comNew

    Availability unknown

    $25.99Observed Nov 1, 2026, 12:08 PM
    Visit staples.com

Also available at

  • WalmartCheck price at Walmart
  • eBayCheck price at eBay

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All 9 stores and price history →

Texas Instruments TI-36X Pro

  • Best BuyNew

    In stock

    $27.35Observed at 9:55 PM
    Visit Best Buy

Also available at

  • eBayCheck price at eBay
  • QuillCheck price at Quill
  • OnTimeSupplies.comCheck price at OnTimeSupplies.com

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Prices and history →

Specs compared

SpecCasio fx-991CW Scientific CalculatorTexas Instruments TI-36X Pro
ColorGrayfalse
Solar PoweredYesYes
Digit Count2 digits16 digits
size6.4" tall x 3.0" wide x 0.4" deep—
TypeHandheld—
Function—Scientific
Brand—Texas Instruments
Model Number—36PRO/TBL/1L1/A
Warranty - Parts—Manufacturer's limited one-year warranty.
Warranty - Labor—1 year
Product Width—3.38 inches
Product Height—3.39 inches
Show all 19 specsShow fewer specs
SpecCasio fx-991CW Scientific CalculatorTexas Instruments TI-36X Pro
Product Length—7.25 inches
Product Weight—0.37 ounces
Display Type—LCD
Power Source—Battery-powered/Solar powered
Number Of Keys—7
Number Of Functions—1
Number Of Display Lines—4

What reviewers say

Casio fx-991CW Scientific Calculator

  • 4.6 / 562 ratings

Owners rate the fx-991CW highly, with 4.6 out of 5 from 62 ratings. Most praise the sharp display and the easier menu system, while a few miss the direct keys of the older fx-991EX.

What people mention
  • DisplayPraisedOwners say the high-resolution screen makes fractions, roots and long equations easy to read.
  • InterfaceMixedThe icon-based menu is praised as easier to learn but criticised as slower than direct function keys.
  • BuildPraisedReviewers describe the calculator as sturdy and well made for daily classroom use.
  • PowerPraisedThe solar panel with battery backup is reported to keep the calculator running without frequent battery changes.

Texas Instruments TI-36X Pro

  • 4.7 / 51,000 ratings

Reviewers rate it very highly and treat it as the best non-graphing scientific calculator TI makes. Engineering students and professionals praise the textbook-style display and the breadth of functions. Complaints center on the learning curve and the crowded keypad.

What people mention
  • DisplayPraisedOwners like seeing stacked fractions and radicals exactly as written in textbooks.
  • FunctionsPraisedReviewers value matrices, vectors, complex numbers and conversions in a non-graphing body.
  • Learning curveMixedSome say the extra functions take practice to find and use fluently.
  • KeypadCriticised

Questions and answers

Which is better for engineering courses?
The TI-36X Pro is the safer pick for engineering and technical courses. It has a long classroom history and a four-line display for checking multi-step work. The Casio fx-991CW works fine but is newer and less proven in that setting.
Which is easier to learn?
The TI-36X Pro is easier for most people coming from older scientific calculators because of its direct function keys. The Casio fx-991CW uses an icon menu that is clean once learned but takes a session to get used to.
Does either show fractions and roots like a textbook?
Both do. The Casio uses its natural display, and the TI uses MathPrint with stacked fractions and symbols. The TI adds a dedicated toggle key to switch between fractions or roots and decimals.
Which lasts longer?
Both run on solar with battery backup, so daily use is not a concern. The TI-36X Pro has a longer field record and a one-year manufacturer warranty. Build quality is comparable; the Casio is slimmer and the TI is chunkier.
Is the Casio worth stepping up to over the TI?
Step up to the Casio if you prefer a modern menu interface and a sharper screen. Stay with the TI if you want the familiar key layout and the confidence of a long track record.
Can I use either on standardized exams?
Both are standard scientific calculators without graphing or programming, which most exam boards permit. Check your specific exam's approved list before test day.

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Some find the keys small and the labels crowded on the compact body.