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
Apoapsis and periapsis calculator
from semi-major axis and eccentricity, free
POST /astro/apoapsis-periapsis$0.002
Developer Utilities
Apparent brightness calculator
L/(4πd²) inverse square, free
POST /astro/apparent-brightness$0.002
Developer Utilities
Planet escape velocity calculator
v = √(2GM/r), free
POST /astro/body-escape-velocity$0.002
Developer Utilities
Distance modulus calculator
parsecs & light-years, free
POST /astro/distance-modulus$0.002
Developer Utilities
Geostationary orbit calculator
altitude from mass and rotation period, free
POST /astro/geostationary-orbit$0.002
Developer Utilities
Gravitational force calculator
Newton's law F=Gm₁m₂/r² free
POST /astro/gravitational-force$0.002
Developer Utilities
Hubble law calculator
galaxy distance from recession velocity and H0, free
POST /astro/hubble-distance$0.002
Developer Utilities
Light-year converter
km, parsecs and AU, free
POST /astro/light-year-distance$0.002
Developer Utilities
Orbital energy calculator
potential and total energy from mass and radius, free
POST /astro/orbital-energy$0.002
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Orbital period calculator
Kepler T from semi-major axis and mass, free
POST /astro/orbital-period$0.002
Developer Utilities
Orbital velocity calculator
circular speed from mass and radius, free
POST /astro/orbital-velocity$0.002
Developer Utilities
Stellar parallax calculator
star distance from parallax angle in parsecs and light-years, free
POST /astro/parallax-distance$0.002
Developer Utilities
Redshift calculator
z and recession velocity from wavelengths, free
POST /astro/redshift-velocity$0.002
Developer Utilities
Roche limit calculator
tidal breakup distance from densities and radius, free
POST /astro/roche-limit$0.002
Developer Utilities
Synodic period calculator
from two orbital periods, free
POST /astro/synodic-period$0.002
Developer Utilities
Rocket equation calculator
Δv = ve·ln(m₀/m_f), free
POST /astro/tsiolkovsky-rocket$0.002
Developer Utilities
Weight on other planets calculator
Earth weight to Mercury Mars Jupiter free
POST /astro/weight-on-planet$0.002
Developer Utilities
Actual yield calculator
from theoretical yield and percent yield, free
POST /chem/actual-yield-from-percent$0.002
Developer Utilities
Activation energy calculator
Ea from two rate constants, free
POST /chem/arrhenius-activation-energy$0.002
Developer Utilities
Arrhenius pre-exponential factor calculator
A from k, Ea, T, free
POST /chem/arrhenius-prefactor$0.002
Developer Utilities
Atom economy calculator
green chemistry AE free
POST /chem/atom-economy$0.002
Developer Utilities
Atoms to moles of compound calculator
n = N/(k·N_A), free
POST /chem/atoms-to-moles-of-compound$0.002
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Average atomic mass calculator
from isotope masses and abundances
POST /chem/average-atomic-mass$0.002
Developer Utilities
Average kinetic energy of gas calculator
(3/2)kT per molecule, free
POST /chem/average-kinetic-energy-gas$0.002
Developer Utilities
Avogadro's law calculator
final gas volume from moles, free
POST /chem/avogadro-law$0.002
Developer Utilities
Moles to atoms calculator
Avogadro's number N = n·N_A, free
POST /chem/avogadro-number$0.002
Developer Utilities
Bomb calorimeter calculator
molar heat of combustion from C, ΔT, n
POST /chem/bomb-calorimetry$0.002
Developer Utilities
Bond energy reaction enthalpy calculator
ΔH from bonds
POST /chem/bond-enthalpy-reaction$0.002
Developer Utilities
Boyle's law calculator
final gas pressure from volume, free
POST /chem/boyle-final-pressure$0.002
Developer Utilities
Boyle's law final volume calculator
V2 from P1, V1, P2 at constant T, free
POST /chem/boyle-final-volume$0.002
Developer Utilities
Buffer capacity calculator
β from acid and conjugate base, free
POST /chem/buffer-capacity$0.002
Developer Utilities
Buffer pOH calculator
pOH from pKb and concentrations, free
POST /chem/buffer-poh$0.002
Developer Utilities
C1V1 = C2V2 calculator
solve dilution for concentration or volume, free
POST /chem/c1v1-c2v2$0.002
Developer Utilities
Calorimeter constant calculator
C = q/ΔT from heat and temperature change
POST /chem/calorimeter-constant$0.002
Developer Utilities
Calorimetry heat released calculator
Q = m·c·ΔT from mass, specific heat and ΔT, free
POST /chem/calorimetry-heat$0.002
Developer Utilities
Catalyst rate enhancement calculator
k_cat/k_uncat from Ea, free
POST /chem/catalyst-rate-enhancement$0.002
Developer Utilities
Cell potential from Gibbs free energy
E° = −ΔG°/(nF)
POST /chem/cell-potential-from-gibbs$0.002
Developer Utilities
Charles law final temperature calculator
T2 from V1, T1, V2 free
POST /chem/charles-final-temperature$0.002
Developer Utilities
Clausius–Clapeyron calculator
T2 from two vapor pressures, free
POST /chem/clausius-clapeyron$0.002
Developer Utilities
Colligative particle concentration calculator
M×i effective particles, free
POST /chem/colligative-particle-count$0.002
Developer Utilities
Collision theory rate calculator
k = p·Z·e^(−Ea/RT), free
POST /chem/collision-frequency-factor$0.002
Developer Utilities
Combined equilibrium constant calculator
overall K from steps, free
POST /chem/combined-equilibrium-constant$0.002
Developer Utilities
Combined gas law final pressure calculator
P2 from V2, T2 free
POST /chem/combined-gas-final-pressure$0.002
Developer Utilities
Combustion analysis calculator
empirical formula from CO2 and H2O, free
POST /chem/combustion-analysis$0.002
Developer Utilities
Common ion effect solubility calculator
reduced molar solubility from Ksp, free
POST /chem/common-ion-solubility$0.002
Developer Utilities
Gas compressibility factor calculator
Z = PVm/RT for real gases, free
POST /chem/compressibility-factor$0.002
Developer Utilities
Concentration after evaporation calculator
concentrated solution from volume lost, free
POST /chem/concentration-after-evaporation$0.002
Developer Utilities
Conjugate base to acid ratio calculator
[A−]/[HA] from pH and pKa, free
POST /chem/conjugate-ratio$0.002
Developer Utilities
Faraday corrosion rate calculator
penetration rate from i_corr, free
POST /chem/corrosion-rate-faraday$0.002
Developer Utilities
Van der Waals critical constants calculator
Tc, Pc, Vc from a and b, free
POST /chem/critical-constants$0.002
Developer Utilities
Partial pressures from mole amounts
Dalton Pi=(ni/n)·P, free
POST /chem/dalton-from-moles$0.002
Developer Utilities
Gas mole fraction from partial pressure
Dalton yi=Pi/P, free
POST /chem/dalton-mole-fraction$0.002
Developer Utilities
Degree of dissociation calculator
α from C₀ and Ceq, free
POST /chem/degree-of-dissociation$0.002
Developer Utilities
Density calculator
ρ=m/V from mass and volume, free
POST /chem/density-mass-volume$0.002
Developer Utilities
Dilution calculator
solve M1V1=M2V2 for concentration or volume
POST /chem/dilution$0.002
Developer Utilities
Dilution factor calculator
DF and fold dilution from volumes
POST /chem/dilution-factor-from-volumes$0.002
Developer Utilities
pH after dilution calculator
strong acid pH from volumes, free
POST /chem/dilution-ph-strong-acid$0.002
Developer Utilities
Dilution to target ppm calculator
stock volume for a final ppm
POST /chem/dilution-to-target-ppm$0.002
Developer Utilities
Dilution water to add calculator
volume from C1 V1 C2 free
POST /chem/dilution-water-added$0.002
Developer Utilities
Ebullioscopic constant calculator
Kb from ΔTb, molality and van't Hoff factor
POST /chem/ebullioscopic-constant$0.002