I'm a student. One day I thought: Why bother carrying the old fashioned TI-84 around if I have my laptop? Kalker is definitely close but I haven't found any calculator that I really liked, so here I'm building myself one👇

Calculator CLI

A terminal-based scientific calculator supporting basic math, scientific functions, imaginary numbers, and LaTeX syntax input.

Built-in Constants

Constant	Value	Description	Field
pi	3.14159265358979	π
e	2.718281828459045	Euler's number
tau	6.283185307179586	τ = 2π
g	9.80665	Standard gravity (m/s²)	Physics
c	299792458	Speed of light (m/s)	Physics
G	6.67430×10⁻¹¹	Gravitational constant (m³/kg·s²)	Physics
h	6.62607015×10⁻³⁴	Planck constant (J·s)	Physics
k	1.380649×10⁻²³	Boltzmann constant (J/K)	Physics
mu0	1.25663706212×10⁻⁶	Vacuum permeability (N/A²)	Physics
eps0	8.8541878128×10⁻¹²	Vacuum permittivity (F/m)	Physics
NA	6.02214076×10²³	Avogadro constant (mol⁻¹)	Chemistry
R	8.31446261815324	Ideal gas constant (J/mol·K)	Chemistry
F	96485.33212331001	Faraday constant (C/mol)	Chemistry
atm	101325	Standard atmosphere (Pa)	Chemistry
Vm	22.413969545014137	Molar volume @ STP (L/mol)	Chemistry

LaTeX subscript form: \mu_0, \epsilon_0, \varepsilon_0 are also accepted.

Commands

Command	Description
help / h / ^h	Show help message
quit / q / ^q	Exit the calculator
yes_i / yes_j	Switches between i and j fo display of imaginary unit as (input accepts both i and j)
i_root	Toggle display of imaginary/complex roots in equation solving
radian / degree	Toggle angle input mode for trigonometric functions

• Imaginary unit display: By default, imaginary units are displayed as j. Typing yes_i changes the output to use i, and yes_j reverts to j. Both j and i are always accepted as input.
• Imaginary roots: When equation solving (x^2 + 1 = 0), toggling i_root off filters results to show only real roots.
• Angle mode: In degree mode, sin(90) = 1 and asin(1) = 90. Default is radian mode.

LaTeX Input

The calculator supports LaTeX-style syntax for many operations:

Input	Display	Example
\frac{num}{den}	num/den	\frac{1}{2} → 0.5
\sqrt{rad}	√rad	\sqrt{144} → 12
\sqrt[n]{rad}	∛rad, ∜rad, rad^(1/n)	\sqrt[3]{8} → 2
\sin{arg}	sin(arg)	\sin{0} → 0
\pi, \tau, etc.	π, τ	\pi → 3.141593
\mu_0, \epsilon_0	constants	Permittivity, permeability

Definite Integrals (Numerical)

Numerical integration using adaptive Simpson's rule:

\int_0^1 2x dx              → 1
\int_0^{pi} sin(x) dx       → 2
\int_0^1 \int_0^2 x*y dy dx → 1

Supports any nesting depth. Bounds can be braced {0} or unbraced 0. Use d{var} to specify the integration variable. Also supports \iint (∬) and \iiint (∭) notation.

Summations

\sum_{n=0}^{5} n^2                            → 55
\sum_{i=1}^{3} \sum_{j=1}^{2} i*j            → 18
\sum^{3}_{i=1} 3i                            → 18  (reversed bounds also work)

Supports any nesting depth. Both _lower^upper and ^upper_lower orderings are accepted.

Numerical Derivatives

Evaluate derivatives at a point using central finite differences:

d/dx_3 x^2          → 6        (first derivative at x=3)
d^2/dx^2_3 x^3     → 18       (second derivative at x=3)
d/dx_0 sin(x)       → 1        (d/dx sin(x) at x=0)

Supports higher-order derivatives via d^n/dx^n or dn/dxn notation.

Notes

• In integrals, sums, and derivatives, i is treated as a variable name (not the imaginary unit). Use j explicitly for the imaginary unit in these expressions.
• Numerical integration uses adaptive Simpson's rule with a tolerance of 1e-8.
• Derivatives use central finite differences with adaptive step sizes.
• For sums, only the {var=start} braced subscript form is supported.