Developer Utilities
Small developer utilities that save a trip to a random website. Encode and decode Base64, explain a regex, build UTM links, generate QR codes and vCards, and more — the everyday helpers. Free in your browser, and available by API when you need them in a script.
Developer Utilities
Prime quadruplet finder
list p, p+2, p+6, p+8 up to n
POST /numth/prime-quadruplet$0.002Developer Utilities
Right-Truncatable Prime Checker
Test Every Trailing-Digit Cut
POST /numth/right-truncatable-prime$0.002Developer Utilities
Strobogrammatic number checker
180° rotation reads the same
POST /numth/strobogrammatic-number$0.002Developer Utilities
Wilson prime checker
does p² divide (p−1)!+1?
POST /numth/wilson-prime$0.002Developer Utilities
Digit frequency counter
count decimal digits
POST /numth/digit-frequency$0.002Developer Utilities
Product of digits calculator
multiply decimal digits
POST /numth/digit-product$0.002Developer Utilities
Extravagant number checker
prime factorization digit count vs n
POST /numth/extravagant-number$0.002Developer Utilities
Golomb sequence calculator
n-th term of the self-describing sequence
POST /numth/golomb-sequence$0.002Developer Utilities
Gray code decoder
convert Gray binary to an integer
POST /numth/gray-code-decode$0.002Developer Utilities
Palindrome bases finder
list bases where n is a palindrome
POST /numth/palindrome-bases-list$0.002Developer Utilities
Super-prime checker
test primes whose index is also prime
POST /numth/super-prime$0.002Developer Utilities
Ulam sequence calculator
first n Ulam numbers
POST /numth/ulam-sequence$0.002Developer Utilities
Line intercept form calculator
find slope-intercept and standard forms
POST /algebra/line-from-intercepts$0.002Developer Utilities
Discriminant and root type calculator
Δ and real roots, free
POST /algebra/quadratic-discriminant-type$0.002Developer Utilities
Quadratic y-intercept calculator
find the parabola intercept
POST /algebra/quadratic-y-intercept$0.002Developer Utilities
Standard form of a line calculator
Ax + By = C with integer coefficients
POST /algebra/standard-form-line$0.002Developer Utilities
Height of a square pyramid
from base side and volume online
POST /math/height-of-a-square-pyramid$0.002Developer Utilities
Height of a cone calculator
from volume and base radius
POST /math/height-of-cone$0.002Developer Utilities
Legendre formula calculator
exponent of a prime in n!
POST /numth/legendre-formula$0.002Developer Utilities
Reduced binary quadratic forms
list primitive forms by discriminant
POST /numth/reduced-binary-forms$0.002Developer Utilities
Tetranacci number calculator
nth term, sum of the previous four
POST /numth/tetranacci$0.002Developer Utilities
Absolute Value Greater-Than Inequality Solver
Interval Union
POST /algebra/absolute-value-inequality-greater$0.002Developer Utilities
Augmented matrix solver
solve [A|b] for unique, infinite, or no solution
POST /algebra/augmented-matrix-solver$0.002Developer Utilities
Cubic discriminant calculator
classify real roots
POST /algebra/cubic-discriminant$0.002Developer Utilities
Descartes rule of signs calculator
positive and negative real roots
POST /algebra/descartes-rule-of-signs$0.002Developer Utilities
Direct variation calculator
y = kx, find k and predict values
POST /algebra/direct-variation$0.002Developer Utilities
Horner method calculator
evaluate polynomial coefficients
POST /algebra/horner-method$0.002Developer Utilities
Quadratic maximum-minimum calculator
vertex of ax²+bx+c, free
POST /algebra/quadratic-max-min$0.002Developer Utilities
Quartic equation from roots calculator
expand four factors
POST /algebra/quartic-from-roots$0.002Developer Utilities
Height of a cylinder calculator
from volume and base radius
POST /math/height-of-cylinder$0.002Developer Utilities
Heptagon calculator
interior angles, perimeter and area
POST /math/heptagon$0.002Developer Utilities
Compound inequality solver
AND/OR to interval notation, free
POST /algebra/compound-inequality$0.002Developer Utilities
Factor trinomial calculator
factor ax² + bx + c over integers
POST /algebra/factor-trinomial$0.002Developer Utilities
Vertical shift of a function calculator
move a graph up or down
POST /algebra/function-vertical-shift$0.002Developer Utilities
Polynomial LCM calculator
least common multiple using GCD
POST /algebra/polynomial-lcm$0.002Developer Utilities
Simplify rational expression calculator
factor, cancel, excluded values
POST /algebra/rational-expression-simplify$0.002Developer Utilities
Rational function x-intercepts calculator
zeros of N in domain
POST /algebra/rational-function-x-intercepts$0.002Developer Utilities
System of linear inequalities calculator
boundaries and corner points
POST /algebra/system-of-inequalities$0.002Developer Utilities
Hexagonal pyramid surface area
from base side and slant height, free
POST /math/hexagonal-pyramid-surface-area$0.002Developer Utilities
Hilbert's hotel paradox
shift every guest and free rooms for new arrivals
POST /math/hilberts-hotel-paradox$0.002Developer Utilities
Complex Reciprocal Calculator
Find 1/z
POST /algebra/complex-reciprocal$0.002Developer Utilities
Complex to polar form calculator
find modulus and argument
POST /algebra/complex-to-polar$0.002Developer Utilities
Exponential growth calculator
future value and growth factor
POST /algebra/exponential-growth$0.002Developer Utilities
Exponential equation same-base solver
rewrite bases, equate exponents
POST /algebra/exponential-same-base$0.002Developer Utilities
Function zeros calculator
real roots of f(x) = 0, free
POST /algebra/function-zeros$0.002Developer Utilities
Hyperbolic functions calculator
sinh, cosh and tanh online
POST /math/hyperbolic-functions$0.002Developer Utilities
Imaginary unit powers
compute i raised to any integer exponent
POST /math/imaginary-number$0.002Developer Utilities
Improper fraction to mixed number converter
whole part and remainder
POST /math/improper-fraction-to-mixed-number$0.002Developer Utilities
Inscribed angle calculator
angle from intercepted arc, free online
POST /math/inscribed-angle$0.002Developer Utilities
Common Difference Calculator
Check an Arithmetic Sequence
POST /algebra/arithmetic-common-difference$0.002Developer Utilities
Arithmetic mean calculator
average of a list of numbers, free
POST /algebra/arithmetic-mean$0.002Developer Utilities
Distance between complex numbers calculator
|z₁−z₂| in the plane
POST /algebra/complex-distance$0.002Developer Utilities
Complex number from modulus and argument calculator
rectangular form
POST /algebra/complex-from-modulus-argument$0.002Developer Utilities
Exponential function from two points
y = a·b^x, free
POST /algebra/exponential-model-from-two-points$0.002Developer Utilities
Matrix scalar multiplication calculator
scale every entry
POST /algebra/matrix-scalar-multiply$0.002Developer Utilities
Sequence Term from Explicit Formula Calculator
POST /algebra/sequence-term-from-formula$0.002Developer Utilities
Sum of first n even numbers calculator
S = n(n+1)
POST /algebra/sum-of-even-numbers$0.002Developer Utilities
Integer checker
test whether a value is a whole number
POST /math/integer$0.002Developer Utilities
Integration by completing the square
arctangent antiderivative, free
POST /math/integration-by-completing-the-square$0.002Developer Utilities
Binomial expansion specific term calculator
coefficient and powers
POST /algebra/binomial-specific-term$0.002