Maths / Calculate
Casio fx-991CW Alternative: Free Online Scientific Calculator
Use an independent scientific calculator with an fx-991CW compatible keypad and menu workflow. Calculate fractions, statistics, equations, distributions and matrix inverses locally.
Casio fx-991CW Alternative: Free Online Scientific Calculator: Students moving to the fx-991CW often need to learn a different route to familiar maths. This page starts in Calculate with the CW keypad: HOME chooses the app, SETTINGS changes calculation preferences, TOOLS opens the current app's calculations and CATALOG lists the available operations. Unlike the EX, the CW has no ALPHA key. Its SHIFT legends include constants and letters, and VARIABLE offers stored values. The arrow controls and OK provide menu selection; the back key leaves the current menu. EXE evaluates an expression or advances a parameter prompt. The FORMAT menu is central to the CW workflow. After evaluating 1/2 + 1/3, choose Decimal to see 0.8333333333, or choose Standard to restore the exact fraction. Other format choices include mixed fractions, prime factors, polar coordinates, sexagesimal angles and engineering notation. Use FUNCTION to save expressions for f(x) and g(x), then enter the functions in the Table prompts to generate rows over a chosen range. HOME places Statistics and Distribution near the beginning of the app list, making them convenient for repeated classroom exercises. Enter observations one at a time with EXE and use TOOLS to inspect the summary or linear regression. The interface remembers history, observations and variable values in this browser, so you can reload the page and continue working. It is an independent implementation with simplified menus and its own visual design. There is no manufacturer software, account or upload. For the earlier key-driven flow, open the EX alternative; the scientific calculator supplies larger editors for longer matrices and data sets. Runs 100% locally in your browser with zero server file uploads.
- Category
- School & study tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
CASIO, ClassWiz and Natural Textbook Display are trademarks or registered trademarks of CASIO Computer Co., Ltd. TOEA is not affiliated with or endorsed by CASIO. This is an independent calculator with a compatible key layout; it does not run CASIO software.
Student tasks on the CW keypad
Distributions: HOME → Distribution offers Normal PD, Normal CD, Inverse Normal, Binomial PD/CD and Poisson PD/CD. For discrete distributions choose Variable or List; List accepts up to 45 comma-separated x values and returns a result for each.
Inequality: HOME → Inequality → Inequality, select degree 2, 3 or 4 and a relation (> 0, < 0, ≥ 0 or ≤ 0), then fill the coefficient grid. For x²−5x+6 > 0 the result is x<2, 3<x.
Fraction to decimal: 1 ÷ 2 + 1 ÷ 3 → EXE → FORMAT → Decimal. Standard returns to 5/6. The CW replaces the EX's S⇔D flow with FORMAT.
Degrees: SETTINGS → Angle Unit → Degree. SHIFT applies to the next key only; SHIFT → sin inserts the inverse sine function.
Statistics and regression: HOME → Statistics. Enter observations with EXE after each value. TOOLS → One-variable results gives n, x̄, sums, σx, sx, quartiles and extrema. Enter x y pairs for regression, then TOOLS → Linear regression to read the statistical variables and a, b and r. TOOLS → ŷ or x̂ estimates values using the current regression.
nCr: CATALOG → nCr → 5 → EXE → 2 → EXE gives 10. This simplified catalogue does not reproduce the full device category tree.
Equation solving: HOME → Equation → Quadratic. Enter 1, −5 and 6 with EXE after each coefficient. For a 2×2 system, choose Simultaneous equations and fill the grid rows with 2, 1, 5 and 1, −1, 1, then Execute; read x = 2 and y = 1.
Integration: CATALOG → Integral. Enter x², lower bound 0 and upper bound 1, pressing EXE at each prompt, to obtain 1/3.
Matrix inverse: HOME → Matrix → Matrix inverse. Choose a 2×2 grid, enter 1, 2, 3 and 4 in its cells, then Execute. The inverse is −2, 1; 1.5, −0.5.
Base conversion: HOME → Base-N → Base conversion → 255 → EXE gives FF. Choose Hex AND for FF and 0F to obtain F.
Normal distribution: HOME → Distribution → Normal CD. Enter −1, 1, 1 and 0 for the bounds, standard deviation and mean. Inverse Normal uses Area, σ and μ, with a left tail.
Result formats: evaluate 360 → FORMAT → Prime factor for 2³×3²×5. Evaluate 12345 → FORMAT → Engineering for 12.345×10³. Back leaves a menu without evaluating.
What is not supported
Spreadsheet and Math Box are unavailable. The menu categories, variable editor, function storage and number-format settings are simplified. There is no complete device catalogue, QR-code export or hardware display control. FORMAT conversions for numerical calculus results are approximate rather than symbolic.
CW key names and formats
CASIO fx-570CW/fx-991CW User's Guide (edu.casio.com) describes HOME, SETTINGS, CATALOG, TOOLS, VARIABLE and FORMAT, including engineering and sexagesimal output. Functional legends are used to help students find the corresponding operation. Guide text and photographs are not copied into the page.
Constants, conversions and statistics
CODATA 2018 recommended values and NIST SP 811 supply the displayed constant subset and exact conversion factors. NIST/SEMATECH e-Handbook of Statistical Methods explains means, standard deviations, linear regression and probability distributions. Measured constants and numerical probabilities carry rounding uncertainty.
How to use it
- Choose an app from HOME, using its displayed number or the arrows and OK.
- Enter a calculation and press EXE. SHIFT changes the next key; the CW has no ALPHA key.
- Use CATALOG for calculations, VARIABLE for saved values, and FORMAT to change a displayed answer.
Privacy & limitations
Entries and saved calculator state remain in this browser. No calculation is uploaded.
Related tools
Frequently asked questions
Is this a CASIO calculator?
CASIO, ClassWiz and Natural Textbook Display are trademarks or registered trademarks of CASIO Computer Co., Ltd. TOEA is not affiliated with or endorsed by CASIO. This is an independent calculator with a compatible key layout; it does not run CASIO software.
Can I use this on an exam?
Check the rules for your exam and use only the calculator types it permits. Online tools are generally not permitted in proctored exams. This independent page is not approved by CASIO or by an examination board.
Where is S⇔D on the CW?
The CW uses FORMAT instead of the EX's S⇔D key. Evaluate first, press FORMAT, then choose Decimal, Standard, Improper fraction or Mixed fraction.
Does my data leave the browser?
Calculations run locally. This model's saved state remains in browser storage until you reset it or clear site data.
Free tool · runs in your browser · no account required