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May 14, 2023 14:37
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A calculator for Windows.

Screen Shot


→ See releases.


  • Displays the evaluation value of a formula in text format.
  • Decimal, hexadecimal, and binary numbers can be mixed.
  • The formula history can be referenced with the up key.
  • The formula history can be modified, and if so, the calculation results are regenerated.
  • Some built-in constants and built-in functions.
  • Identifiers/keywords auto-completion.🆕


Numeric Representations

Representation Example
Decimal 123
Hexadecimal 0x7b, 0x7B
Octadecimal 0173
Binary 0b1111011
SI Prefixed🆕 123k, 456u
Binary Prefixed🆕 123ki, 456Mi
Fraction🆕 2:3
Character 'A'
Date Time #2022/34/56 12:34:56#
Web Color #123, #112233
Boolean🆕 true, false


Category Symbol Precision
Add, Sub, Mul, Div +, -, *, / Decimal
Integral Division // Decimal
Remainder % Decimal
Power ^ Double
Bit NOT ~ Int64
Bit AND & Int64
Bit OR | Int64
XOR +| Int64
Logical Shift <<, >> Int64
Arithmetic Shift <<<, >>> Int64
Compare🆕 >, >=, <, <=, ==, != Decimal
Logical NOT🆕 ! Boolean
Logical AND🆕 && Boolean
Logical OR🆕 || Boolean

Embedded Functions

Category Functions Precision
Exponential sqrt(x), log(x), log2(x), log10(x), clog2(x), clog10(x) Double
Trigonometric sin(x), cos(x), tan(x),asin(x), acos(x), atan(x), atan2(y, x),sinh(x), cosh(x), tanh(x) Double
Round floor(x), ceil(x), trunc(x), round(x) Decimal
Absolute/Sign abs(x), sign(x) Decimal
Max/Min max(...), min(...) Decimal
Sum/Average🆕 sum(...), ave(...), harmean(...), invsum(...), geomean(...) Decimal
GCD, LCM🆕 gcd(a, b), lcm(a, b) Decimal
Bit/Byte Operations🆕 swapnib(x), swap2(x), swap4(x), swap8(x), reverse(x,w), reverseb(x), rotatel(x,w), rotater(x,w), count1(x,w) Int64
Parity/ECC🆕 xorreduce(x), parity(x), eccwidth(x), eccenc(x,w), eccdec(e,x,w) Int64
Gray-code🆕 togray(x), fromgray(x) Int64
Fractions🆕 frac(x)rat(x), frac(x,a)rat(x,a), frac(x,a,b), real(x) Decimal
Representation dec(x), hex(x), bin(x), oct(x), char(x), si(x)🆕, bi(x)🆕, datetime(x) Decimal
Date Time now(), fromyears(x), fromdays(x), fromhours(x), fromminutes(x), fromseconds(x), toyears(x), todays(x), tohours(x), tominutes(x), toseconds(x) Double
Color rgb(r,g,b), rgb(rgb), hsv2rgb(h,s,v), hsv2rgb_r(h,s,v), hsv2rgb_g(h,s,v), hsv2rgb_b(h,s,v), rgb2hsv_h(rgb), rgb2hsv_s(rgb), rgb2hsv_v(rgb), hsl2rgb(h,s,l), hsl2rgb_r(h,s,l), hsl2rgb_g(h,s,l), hsl2rgb_b(h,s,l), rgb2hsl_h(rgb), rgb2hsl_s(rgb), rgb2hsl_l(rgb), yuv2rgb(y,u,v), yuv2rgb(yuv), yuv2rgb_r(yuv), yuv2rgb_g(yuv), yuv2rgb_b(yuv), rgb2yuv(r,g,b), rgb2yuv(rgb), rgb2yuv_y(rgb), rgb2yuv_u(rgb), rgb2yuv_v(rgb) Decimal
E-series Rounding to the E-series value: eXfloor(x), eXceil(x), eXround(x)
Calculation of voltage divider resistance: eXratiol(x), eXratioh(x)
(X=3, 6, 12, 24, 48, 96, 192)
Prime Number🆕 isprime(x), prime(n) Int64
Random🆕 rand(), rand(min, max), rand32(), rand64() Decimal, Int64
Assertion🆕 assert(expr) Boolean
Special🆕 poll(x), alarm(x) any

External Script Call as Functions

Calctus can call scripts such as Python as functions.

Function arguments are passed to the script as command line arguments, and the standard output of the script is returned to Calctus.

  1. Open the Scripts tab in the Calctus Settings dialog.
  2. Check Enable External Script Functions.
  3. If you want to specify the folder where you want to place the scripts, click the Change button to specify the folder.
  4. Click the Open button. If asked if you want to create the folder, click Yes.
  5. Place a python script like the following in the folder.
    import sys
    a = float(sys.argv[1])
    b = float(sys.argv[2])
    print(a + b)
  6. After closing the settings dialog, the add function is now available.

If you wish to use a scripting language other than Python, please register the extension and interpreter in the Scripts tab of the Settings dialog.


Symbol Value
PI 3.1415926535897932384626433833
E 2.7182818284590452353602874714
INT_MIN -2,147,483,648
INT_MAX 2,147,483,647
UINT_MAX 4,294,967,295
LONG_MIN -9,223,372,036,854,775,808
LONG_MAX 9,223,372,036,854,775,807
ULONG_MAX 18,446,744,073,709,551,615
DECIMAL_MIN -79,228,162,514,264,337,593,543,950,335
DECIMAL_MAX 79,228,162,514,264,337,593,543,950,335

User-defined constants can also be used. 🆕


Variables can be assigned using the equal sign.

a = 2 [Return]
b = 3 [Return]
a * b [Return]
// --> Calctus answers 6.



RPN Operations🆕

If only an operator is entered, the expression is "popped" from the history and combined with that operator.

If you use RPN operation, it is recommended to turn off the automatic input of "ans" in the settings.

1 [Return]
2 [Return]
+ [Return] // "1" and "2" replaced with "1+2"
3 [Return]
4 [Return]
+* [Return] // "1+2", "3" and "4" replaced with "(1+2)*(3+4)"


Keyboard Shortcut

Key Function
Shift + Return Insert
Shift + Delete Delete current expression
Ctrl + X Cut
Ctrl + C Copy
Ctrl + Shift + C Copy all expressions and answers
Ctrl + V Copy
Ctrl + Shift + V🆕 Multiline Paste
Ctrl + Shift + N🆕 Insert current time
Ctrl + Shift + Del Delete all expressions
Ctrl + Shift + Up Item move up
Ctrl + Shift + Down Item move down
F1🆕 Help
F5🆕 Recalculation
F8 Radix Mode = Auto
F9 Radix Mode = Dec
F10 Radix Mode = Hex
F11 Radix Mode = Bin
F12 Radix Mode = Oct