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
Lesson plan time budget
allocate class minutes by activity weight
POST /edu/lesson-plan-time-budget$0.002Developer Utilities
Shuffle quiz answer choices with a seed
keep the correct index
POST /edu/multiple-choice-shuffle-seeded$0.002Developer Utilities
Dragon Boat Festival date
free
POST /date/dragon-boat-festival$0.002Developer Utilities
Seeded Giveaway Winner Picker
Reproducible Weighted Draw
POST /game/giveaway-winner-pick$0.002Developer Utilities
Filter Wordle candidate words by green, yellow and gray clues
POST /game/wordle-solver-filter$0.002Developer Utilities
Anagram solver against a dictionary
find every possible word
POST /game/anagram-solver-dictionary$0.002Developer Utilities
Ex-meridian reduction latitude
free
POST /geo/ex-meridian$0.002Developer Utilities
Check a Valid Word Ladder Step
One-Letter Difference
POST /game/word-ladder-step-check$0.002Developer Utilities
Validate chess algebraic notation
SAN syntax checker
POST /game/chess-algebraic-validate$0.002Developer Utilities
Trivia quiz score calculator with speed bonuses
POST /game/trivia-score-calc$0.002Developer Utilities
Calculate Scrabble Word Score with Letter and Word Multipliers
POST /game/scrabble-word-score$0.002Developer Utilities
Blackjack Hand Value Calculator
Count Aces Correctly
POST /game/blackjack-hand-value$0.002Developer Utilities
Calculate cart abandonment rate from carts and checkouts
POST /ecom/cart-abandonment-rate$0.002Developer Utilities
Calculate target price for margin from product cost
POST /ecom/product-margin-target-price$0.002Developer Utilities
Calculate average order value from revenue and orders
POST /ecom/average-order-value$0.002Developer Utilities
Angular momentum calculator
L = Iω in kg·m²/s
POST /mech/angular-momentum$0.002Developer Utilities
Hollow Cylinder Moment of Inertia Calculator
POST /mech/moment-of-inertia-cylinder-hollow$0.002Developer Utilities
Rod moment of inertia about one end
I = (1/3) m L² free
POST /mech/moment-of-inertia-rod-end$0.002Developer Utilities
Rotational Power Calculator
Torque Times Angular Velocity
POST /mech/rotational-power$0.002Developer Utilities
Angular to arc distance calculator
wheel travel from radians
POST /mech/angular-to-arc-distance$0.002Developer Utilities
Gravitational field strength calculator
g = GM/r² free
POST /mech/gravitational-field-strength$0.002Developer Utilities
Hollow sphere moment of inertia
thin shell I = ⅔ m r²
POST /mech/moment-of-inertia-sphere-hollow$0.002Developer Utilities
Rolling shapes race calculator
rank acceleration by inertia
POST /mech/rolling-race$0.002Developer Utilities
Torque Wrench Force Calculator
Force from Torque and Length
POST /mech/torque-wrench$0.002Developer Utilities
Escape energy calculator
kinetic energy needed to leave a planet
POST /mech/escape-energy$0.002Developer Utilities
Gravitational potential calculator
Φ = −GM/r free
POST /mech/gravitational-potential$0.002Developer Utilities
Orbit altitude from period calculator
h from T, mass and radius, free
POST /mech/orbital-altitude-from-period$0.002Developer Utilities
Synchronous orbit radius calculator
planet mass and day length
POST /mech/synchronous-orbit-radius$0.002Developer Utilities
Vis-viva calculator
orbital speed from radius and semi-major axis
POST /mech/vis-viva$0.002Developer Utilities
Compare fractions
which of a/b and c/d is larger
POST /math/comparing-fractions$0.002Developer Utilities
Complementary angle calculator
complement of an acute angle in degrees
POST /math/complementary-angles$0.002Developer Utilities
Mutual gravitational acceleration calculator
a₁=Gm₂/r² free
POST /mech/mutual-gravitational-acceleration$0.002Developer Utilities
SHM maximum acceleration calculator
a max = Aω²
POST /mech/shm-max-acceleration$0.002Developer Utilities
Mass-spring period calculator
T = 2π√(m/k)
POST /mech/shm-period-mass-spring$0.002Developer Utilities
SHM velocity calculator
velocity at a displacement
POST /mech/shm-velocity$0.002Developer Utilities
Compatible numbers
estimate a quotient or product with friendly numbers
POST /math/compatible-numbers$0.002Developer Utilities
Completing the square
rewrite ax²+bx+c as a(x−h)²+k, free
POST /math/completing-the-square$0.002Developer Utilities
Second-class lever calculator
wheelbarrow effort from load and arms
POST /mech/lever-second-class$0.002Developer Utilities
Pendulum bob maximum speed calculator from length and angle
POST /mech/pendulum-bob-speed$0.002Developer Utilities
Oscillator quality factor calculator
resonant frequency and bandwidth
POST /mech/quality-factor$0.002Developer Utilities
Springs in parallel calculator
equivalent spring constant
POST /mech/spring-parallel$0.002Developer Utilities
Completing the square with worked steps
ax²+bx+c to a(x−h)²+k, free
POST /math/completing-the-square-works$0.002Developer Utilities
Complex number calculator
add, subtract, multiply and divide a + bi
POST /math/complex-number$0.002Developer Utilities
Complex number to polar form
magnitude and angle in radians and degrees
POST /math/complex-number-to-polar-form$0.002Developer Utilities
Complex number to rectangular form
real and imaginary parts
POST /math/complex-number-to-rectangular-form$0.002Developer Utilities
Complex number to trigonometric form
modulus and argument of a + bi
POST /math/complex-number-to-trigonometric-form$0.002Developer Utilities
Archimedes principle calculator
buoyant force F_b = ρ V g, free
POST /mech/archimedes-buoyant-force$0.002Developer Utilities
Simply supported beam center load calculator
reactions and maximum moment
POST /mech/beam-point-load-center$0.002Developer Utilities
Will It Float Calculator
Compare Object and Fluid Density
POST /mech/float-or-sink$0.002Developer Utilities
Gear train mechanical advantage calculator
speed and torque ratios
POST /mech/gear-train-advantage$0.002Developer Utilities
Gravitational force comparison
two mass and distance setups
POST /mech/gravitational-force-ratio$0.002Developer Utilities
Hydraulic lift calculator
mechanical advantage and output force
POST /mech/hydraulic-lift-advantage$0.002Developer Utilities
Manometer pressure calculator
ΔP = ρ·g·Δh from fluid density and height
POST /mech/manometer-pressure$0.002Developer Utilities
Pendulum energy calculator
kinetic and potential at any swing angle
POST /mech/pendulum-energy$0.002Developer Utilities
Projectile time at height calculator
find both crossing times
POST /mech/projectile-time-at-height$0.002Developer Utilities
Tipping angle stability
tilt from base width and CG height
POST /mech/tipping-stability$0.002Developer Utilities
Torsional pendulum period
T = 2π√(I/κ) online
POST /mech/torsional-pendulum-period$0.002Developer Utilities
Two-member bracket force calculator
tension and compression
POST /mech/truss-two-member$0.002Developer Utilities
Lucas theorem calculator
C(n,k) mod prime p
POST /numth/lucas-theorem-binomial$0.002Developer Utilities
Modular nth root calculator
all k-th roots of a mod prime p
POST /numth/modular-nth-root$0.002