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
Wind chill calculator
perceived temperature from °C and km/h
POST /weather/wind-chill$0.002Developer Utilities
Entropy calculator
ΔS from Q/T or standard molar entropies, free
POST /chem/entropy$0.002Developer Utilities
Graham's law of diffusion calculator
rate ratio √(M2/M1), free
POST /chem/grahams-law-of-diffusion$0.002Developer Utilities
Heat of combustion calculator
energy from mass and calorific value
POST /chem/heat-of-combustion$0.002Developer Utilities
Langmuir isotherm calculator
fractional coverage θ = KP/(1+KP)
POST /chem/langmuir-isotherm$0.002Developer Utilities
Kp calculator
equilibrium constant from partial pressures
POST /chem/kp$0.002Developer Utilities
Liquid ethylene density calculator
ρ(T) in kg/m³, free
POST /chem/liquid-ethylene-density$0.002Developer Utilities
Miller indices calculator
intercepts to (hkl), free
POST /chem/miller-indices$0.002Developer Utilities
Mixing ratio calculator
g/kg from vapor and total pressure
POST /chem/mixing-ratio$0.002Developer Utilities
Molar ratio calculator
mole ratio from two masses, free
POST /chem/molar-ratio$0.002Developer Utilities
Neutralization calculator
acid or base volume at equivalence
POST /chem/neutralization$0.002Developer Utilities
Percent ionic character calculator
Pauling % from ΔEN, free
POST /chem/percent-ionic-character$0.002Developer Utilities
Net ionic equation calculator
cancel spectator ions free
POST /chem/net-ionic-equation$0.002Developer Utilities
pKa calculator
pKa = −log10(Ka) from Ka, free
POST /chem/pka$0.002Developer Utilities
Raoult's law calculator
partial pressure P = x·P° free
POST /chem/raoults-law$0.002Developer Utilities
Q10 calculator
reaction rate factor from a temperature shift
POST /chem/q10$0.002Developer Utilities
Resuspension calculator
diluent volume from mass and concentration
POST /chem/resuspension$0.002Developer Utilities
Standard temperature and pressure calculator
V, n or P at STP
POST /chem/standard-temperature-and-pressure$0.002Developer Utilities
Titration calculator
unknown analyte concentration from C, V, ratio
POST /chem/titration$0.002Developer Utilities
Vapor pressure calculator
Antoine equation, P in mmHg, free
POST /chem/vapor-pressure$0.002Developer Utilities
Blast radius calculator
peak overpressure distance from TNT, free
POST /phys/blast-radius$0.002Developer Utilities
Bohr model calculator
hydrogen energy and radius from n
POST /phys/bohr-model$0.002Developer Utilities
Boost converter calculator
Vout from Vin and duty cycle, free
POST /phys/boost-converter$0.002Developer Utilities
Bridge rectifier calculator
DC voltage from AC RMS, free
POST /phys/bridge-rectifier$0.002Developer Utilities
Broad-crested weir calculator
discharge Q from width, head, gravity
POST /phys/broad-crested-weir$0.002Developer Utilities
Column buckling calculator
Euler critical load in newtons
POST /phys/buckling$0.002Developer Utilities
Bullet energy calculator
KE = ½mv² in joules, free
POST /phys/bullet-energy$0.002Developer Utilities
Buoyancy experiment calculator
float, force, net weight
POST /phys/buoyancy-experiment$0.002Developer Utilities
Capacitance calculator
parallel-plate C = εA/d in farads, free
POST /phys/capacitance$0.002Developer Utilities
Capacitor calculator
C = εA/d in farads, free
POST /phys/capacitor$0.002Developer Utilities
Capacitor charge time
RC time to a target voltage, free
POST /phys/capacitor-charge-time$0.002Developer Utilities
Carburetor CFM calculator
airflow from CID, RPM and VE, free
POST /phys/carburetor-cfm$0.002Developer Utilities
Car mass center calculator
CG x, y, z from tracks and wheel loads
POST /phys/car-mass-center$0.002Developer Utilities
Centrifuge speed calculator
RPM from rotor radius and RCF
POST /phys/centrifuge-speed$0.002Developer Utilities
Cloud base calculator
height from temperature and dew point
POST /phys/cloud-base$0.002Developer Utilities
Compton scattering calculator
wavelength shift from angle
POST /phys/compton-scattering$0.002Developer Utilities
Compton wavelength calculator
λ = h/(m c) from rest mass
POST /phys/compton-wavelength$0.002Developer Utilities
Contact lens vertex calculator
spectacle to CL power, free
POST /phys/contact-lens-vertex$0.002Developer Utilities
Crawl ratio calculator
first gear, transfer case and axle, free
POST /phys/crawl-ratio$0.002Developer Utilities
Crossover frequency calculator
RC filter cutoff in hertz
POST /phys/crossover$0.002Developer Utilities
Curie's law calculator
magnetization M = C H / T, free
POST /phys/curies-law$0.002Developer Utilities
Cv flow calculator
liquid GPM from Cv, ΔP and specific gravity
POST /phys/cv-flow$0.002Developer Utilities
Cyclotron frequency calculator
f = |q|B/(2πm) in hertz
POST /phys/cyclotron-frequency$0.002Developer Utilities
Daylight hours calculator
duration from day of year and latitude
POST /phys/daylight$0.002Developer Utilities
dB gain calculator
voltage 20·log10 and power 10·log10
POST /phys/db-gain$0.002Developer Utilities
Debye length calculator
plasma screening length in metres
POST /phys/debye-length$0.002Developer Utilities
Cylinder density calculator
ρ from mass, diameter, height
POST /phys/density-cylinder$0.002Developer Utilities
Density mass volume calculator
ρ=m/V for the missing quantity
POST /phys/density-mass-volume$0.002Developer Utilities
Diffraction calculator
angle from slit, wavelength and order
POST /phys/diffraction$0.002Developer Utilities
Electric dipole calculator
axial field E=2kp/r³ or potential
POST /phys/dipole$0.002Developer Utilities
Displacement calculator
s=ut+0.5at² from velocity, time, acceleration
POST /phys/displacement$0.002Developer Utilities
Drift velocity calculator
vd = I/(n·A·q) in m/s, free
POST /phys/drift-velocity$0.002Developer Utilities
Earth curvature calculator
hidden drop below the horizon
POST /phys/earth-curvature$0.002Developer Utilities
Heat exchanger effectiveness-NTU calculator
ε from NTU and C
POST /phys/effectiveness-ntu$0.002Developer Utilities
Elastic constants calculator
E, G, K and Poisson's ratio from any two
POST /phys/elastic-constants$0.002Developer Utilities
Electric motor torque calculator
N·m from power and RPM
POST /phys/electric-motor-torque$0.002Developer Utilities
Electrical mobility
μ = vd/E from drift velocity, free
POST /phys/electrical-mobility$0.002Developer Utilities
E=mc² calculator
rest energy from mass in joules, free
POST /phys/emc2$0.002Developer Utilities
Energy to wavelength calculator
λ = hc/E in metres
POST /phys/energy-to-wavelength$0.002Developer Utilities
Escape velocity calculator
v = √(2GM/r) from mass and radius
POST /phys/escape-velocity$0.002