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
Paper size dimensions
ISO A B C, US Letter, Legal, Tabloid, free
POST /conv/paper-size$0.002Developer Utilities
Paper weight converter
gsm ↔ lb for text, bond, cover, index
POST /conv/paper-weight$0.002Developer Utilities
Power converter
W, kW, MW, hp, BTU/h, ft·lb/s free
POST /conv/power$0.002Developer Utilities
PPM percent converter
ppm, ppb, percent and per-mille free
POST /conv/ppm$0.002Developer Utilities
Radiation exposure converter
C/kg, roentgen, mR, free
POST /conv/radiation-exposure$0.002Developer Utilities
Radioactivity converter
Bq, Ci, Rd and SI multiples, free
POST /conv/radioactivity$0.002Developer Utilities
Electrical resistance converter
ohms, mΩ, kΩ, MΩ, GΩ free
POST /conv/resistance$0.002Developer Utilities
Electrical resistivity converter
Ω·m, Ω·cm, μΩ·cm, Ω·cmil/ft free
POST /conv/resistivity$0.002Developer Utilities
Ring size converter
US, UK, EU and diameter mm equivalents, free
POST /conv/ring-size$0.002Developer Utilities
Roof pitch converter
rise-in-12, degrees and percent slope, free
POST /conv/roof-pitch$0.002Developer Utilities
Shoe size converter
US, UK, EU and cm, men & women, free
POST /conv/shoe-size$0.002Developer Utilities
Slope grade converter
percent grade, degrees and rise-over-run, free
POST /conv/slope-grade$0.002Developer Utilities
Solid angle converter
steradians, deg², spat, sphere free
POST /conv/solid-angle$0.002Developer Utilities
Sound pressure level converter
Pa ↔ dB SPL, free
POST /conv/sound-level$0.002Developer Utilities
Specific energy converter
J/kg, kJ/kg, cal/g, BTU/lb, free
POST /conv/specific-energy$0.002Developer Utilities
Specific heat capacity converter
J/(kg·K), cal/(g·°C), BTU/(lb·°F), free
POST /conv/specific-heat$0.002Developer Utilities
Specific volume converter
m³/kg, L/kg, ft³/lb, free
POST /conv/specific-volume$0.002Developer Utilities
Speed converter
m/s, km/h, mph, knots, ft/s, free
POST /conv/speed$0.002Developer Utilities
Surface tension converter
N/m, mN/m, dyn/cm, lbf/ft, free
POST /conv/surface-tension$0.002Developer Utilities
Thermal conductivity converter
W/(m·K), BTU/(h·ft·°F), cal/(s·cm·°C) free
POST /conv/thermal-conductivity$0.002Developer Utilities
Thermal resistance converter
K/W, °C/W, °F·h/BTU, free
POST /conv/thermal-resistance$0.002Developer Utilities
Time unit converter
seconds, minutes, hours, days, weeks, ms and µs, free
POST /conv/time$0.002Developer Utilities
Torque converter
N·m, N·cm, lbf·ft, lbf·in, kgf·m, free
POST /conv/torque$0.002Developer Utilities
Screen size converter
diagonal in/cm and W×H from aspect ratio, free
POST /conv/tv-size$0.002Developer Utilities
Points to pixels converter
pt, px and picas at 96 DPI, free
POST /conv/typography-pt-px$0.002Developer Utilities
PX to EM converter
CSS pixels ↔ em with base font size, free
POST /conv/typography-px-em$0.002Developer Utilities
px to rem converter
CSS pixels ↔ rem with root font size
POST /conv/typography-px-rem$0.002Developer Utilities
Voltage converter
V, mV, µV, kV, MV, free
POST /conv/voltage$0.002Developer Utilities
Volume converter
liters, gallons, quarts, m³, ft³, free
POST /conv/volume$0.002Developer Utilities
Water hardness converter
ppm, mg/L, gpg, °dH free
POST /conv/water-hardness$0.002Developer Utilities
Wire gauge converter
AWG to mm, inches & area, free
POST /conv/wire-gauge$0.002Developer Utilities
Complete the square calculator
vertex form a(x−h)²+k, free
POST /algebra/complete-the-square$0.002Developer Utilities
Cross product calculator
3D vector a×b and parallelogram area, free
POST /algebra/cross-product$0.002Developer Utilities
Exponent rules calculator
product, quotient, power, free
POST /algebra/exponent-rules$0.002Developer Utilities
Linear inequality solver
ax+b ⊙ c for x, interval form, free
POST /algebra/inequality-solver$0.002Developer Utilities
Matrix inverse calculator
Gauss-Jordan A⁻¹, free
POST /algebra/matrix-inverse$0.002Developer Utilities
Matrix multiplication calculator
A×B product matrix, free
POST /algebra/matrix-multiply$0.002Developer Utilities
Polynomial long division calculator
quotient and remainder, free
POST /algebra/polynomial-divide$0.002Developer Utilities
Polynomial GCD calculator
Euclidean algorithm on coefficients, free
POST /algebra/polynomial-gcd$0.002Developer Utilities
Reduced row echelon form calculator
Gauss-Jordan RREF, free
POST /algebra/rref$0.002Developer Utilities
3×3 system of equations solver
Cramer's rule, free
POST /algebra/system-3x3$0.002Developer Utilities
Absolute magnitude calculator
M from m and distance (pc), free
POST /astro/absolute-magnitude$0.002Developer Utilities
Light travel time calculator
t = d/c from km or AU, free
POST /astro/light-travel-time$0.002Developer Utilities
Planet density calculator
mean bulk density from M and R, free
POST /astro/planet-density$0.002Developer Utilities
Schwarzschild radius calculator
Rs = 2GM/c² event horizon, free
POST /astro/schwarzschild-radius$0.002Developer Utilities
Surface gravity calculator
g = G·M/R² in m/s², free
POST /astro/surface-gravity$0.002Developer Utilities
Telescope resolution calculator
Rayleigh criterion θ=1.22λ/D, free
POST /astro/telescope-resolution$0.002Developer Utilities
Arrhenius equation calculator
k = A·e^(−Ea/RT), free
POST /chem/arrhenius$0.002Developer Utilities
Arrhenius temperature calculator
T from k, A, Ea, free
POST /chem/arrhenius-temperature$0.002Developer Utilities
Average molecular speed calculator
v̄ = √(8RT/πM), free
POST /chem/average-molecular-speed$0.002Developer Utilities
Average rate of reaction calculator
|Δc|/Δt from concentration, free
POST /chem/average-reaction-rate$0.002Developer Utilities
Avogadro's law moles calculator
n₂ = n₁(V₂/V₁), free
POST /chem/avogadro-law-moles$0.002Developer Utilities
Boiling point elevation calculator
ΔTb = i·Kb·m, free
POST /chem/boiling-point-elevation$0.002Developer Utilities
Born-Haber lattice energy calculator
U from formation, sublimation, free
POST /chem/born-haber-cycle$0.002Developer Utilities
Charles's law final volume calculator
V₂ = V₁(T₂/T₁), free
POST /chem/charles-final-volume$0.002Developer Utilities
Vaporization enthalpy calculator
Clausius–Clapeyron ΔHvap from two, free
POST /chem/clausius-clapeyron-enthalpy$0.002Developer Utilities
Combined gas law final volume calculator
V₂ = P₁V₁T₂/(P₂T₁), free
POST /chem/combined-gas-final-volume$0.002Developer Utilities
Cryoscopic constant calculator
Kf = ΔTf/(i·m), free
POST /chem/cryoscopic-constant$0.002Developer Utilities
Decay constant calculator
λ from half-life, free
POST /chem/decay-constant-half-life$0.002Developer Utilities
Degree of dissociation calculator
α from van't Hoff factor i, free
POST /chem/degree-dissociation-from-i$0.002