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
First-order concentration calculator
remaining [A] from k, A₀, t, free
POST /chem/first-order-concentration$0.002
Developer Utilities
Concentration cell potential calculator
E from two ion concentrations
POST /chem/nernst-concentration-cell$0.002
Developer Utilities
Titration unknown concentration
analyte normality N1V1=N2V2
POST /chem/normality-titration$0.002
Developer Utilities
pH from hydrogen ion concentration calculator
pH = −log₁₀([H+])
POST /chem/ph-from-hydrogen-ion$0.002
Developer Utilities
Strong base pH calculator
pH from concentration and OH count, free
POST /chem/ph-strong-base$0.002
Developer Utilities
pKa from buffer pH calculator
acid pKa from pH and base/acid ratio
POST /chem/pka-from-buffer-ph$0.002
Developer Utilities
pKa from Ka calculator
pKa = −log₁₀(Ka) for acids
POST /chem/pka-from-ka$0.002
Developer Utilities
pKa + pKb calculator
conjugate pKb from pKa (sum to 14)
POST /chem/pka-pkb-sum$0.002
Developer Utilities
Titration pH before equivalence calculator
strong acid/base excess pH
POST /chem/titration-ph-before-equivalence$0.002
Developer Utilities
Zero-order concentration calculator
remaining [A] from k, A₀, t, free
POST /chem/zero-order-concentration$0.002
Developer Utilities
Absolute humidity converter
g/m³, grains/ft³, kg/m³ and more, free
POST /conv/absolute-humidity$0.002
Developer Utilities
Absorbance transmittance converter
A, %T, OD and more, free
POST /conv/absorbance-transmittance$0.002
Developer Utilities
Acoustic impedance converter
Pa·s/m, rayls, cgs rayls, free
POST /conv/acoustic-impedance$0.002
Developer Utilities
Acres to square feet converter
exact factor, free
POST /conv/acres-to-square-feet$0.002
Developer Utilities
Bar to kPa converter
exact factor, free in browser
POST /conv/bar-to-kpa$0.002
Developer Utilities
Bar to PSI converter
exact bar factor, free online
POST /conv/bar-to-psi$0.002
Developer Utilities
Barrels to liters converter
exact oil barrel factor, free
POST /conv/barrels-to-liters$0.002
Developer Utilities
BTU per hour to watts converter
exact IT factor, free
POST /conv/btu-per-hour-to-watts$0.002
Developer Utilities
BTU to joules converter
exact International Table factor, free
POST /conv/btu-to-joules$0.002
Developer Utilities
CC to cubic inches converter
exact factor, free
POST /conv/cc-to-cubic-inches$0.002
Developer Utilities
CFM to cubic meters per hour converter
exact factor, free
POST /conv/cfm-to-cubic-meters-per-hour$0.002
Developer Utilities
CM to feet converter
exact 30.48 factor, free in browser
POST /conv/cm-to-feet$0.002
Developer Utilities
Cooling capacity converter
tons of refrigeration, kW, BTU/h free
POST /conv/cooling-capacity$0.002
Developer Utilities
Cubic feet to gallons converter
exact US factor, free
POST /conv/cubic-feet-to-gallons$0.002
Developer Utilities
Cubic inches to cc converter
exact factor, free
POST /conv/cubic-inches-to-cc$0.002
Developer Utilities
Cups to ml converter
exact US factor, free
POST /conv/cups-to-ml$0.002
Developer Utilities
Current density converter
A/m², A/mm², A/in², free
POST /conv/current-density$0.002
Developer Utilities
Damping coefficient converter
N·s/m, lbf·s/ft, lbf·s/in, free
POST /conv/damping-coefficient$0.002
Developer Utilities
Diopter converter
diopters, mm, inches, free
POST /conv/diopter$0.002
Developer Utilities
DPI / PPI resolution converter
dpcm, dpmm and more, free
POST /conv/dpi-ppi$0.002
Developer Utilities
Drill bit size converter
number, letter, fraction & mm, free
POST /conv/drill-bit-size$0.002
Developer Utilities
Earthquake magnitude energy converter
Mw, joules, tons TNT, free
POST /conv/earthquake-energy$0.002
Developer Utilities
Electric dipole moment converter
debye, C·m, a.u., free
POST /conv/electric-dipole-moment$0.002
Developer Utilities
Electronvolts to joules converter
exact SI factor, free
POST /conv/electronvolts-to-joules$0.002
Developer Utilities
Energy density converter
J/m³, Wh/L, BTU/ft³, free
POST /conv/energy-density$0.002
Developer Utilities
EV efficiency converter
Wh/mi, Wh/km, mi/kWh, kWh/100km, free
POST /conv/ev-efficiency$0.002
Developer Utilities
Fahrenheit to Kelvin converter
exact (F−32)×5/9+273.15, free
POST /conv/fahrenheit-to-kelvin$0.002
Developer Utilities
Feet to inches converter
convert feet to inches, free
POST /conv/feet-to-inches$0.002
Developer Utilities
Feet to yards converter
exact factor, free in browser
POST /conv/feet-to-yards$0.002
Developer Utilities
Jansky flux density converter
Jy, mJy, W/m²/Hz, erg units, free
POST /conv/flux-density-jansky$0.002
Developer Utilities
Fracture toughness converter
MPa√m, ksi√in, Pa√m, free
POST /conv/fracture-toughness$0.002
Developer Utilities
Gallons to liters converter
exact US factor, free
POST /conv/gallons-to-liters$0.002
Developer Utilities
Gbps to Mbps converter
exact ×1000 factor, free in browser
POST /conv/gbps-to-mbps$0.002
Developer Utilities
Gemstone carat & point converter
carats, points, grams, grains free
POST /conv/gem-weight$0.002
Developer Utilities
GPM to LPM converter
exact US factor, free
POST /conv/gpm-to-lpm$0.002
Developer Utilities
Grams to carats converter
exact metric factor, free
POST /conv/grams-to-carats$0.002
Developer Utilities
Hectares to square km converter
exact factor, free
POST /conv/hectares-to-square-km$0.002
Developer Utilities
Hounsfield unit converter
HU, attenuation & density
POST /conv/hounsfield$0.002
Developer Utilities
Hz to RPM converter
exact ×60 factor, free
POST /conv/hz-to-rpm$0.002
Developer Utilities
Inches to feet converter
exact factor, free in browser
POST /conv/inches-to-feet$0.002
Developer Utilities
Inches to mm converter
convert inches to millimeters, free
POST /conv/inches-to-mm$0.002
Developer Utilities
inHg to mb converter
exact factor, free in browser
POST /conv/inhg-to-mb$0.002
Developer Utilities
Joules to kWh converter
exact 3.6e6 factor, free
POST /conv/joules-to-kwh$0.002
Developer Utilities
kcal to kJ converter
exact 4.184 factor, free
POST /conv/kcal-to-kj$0.002
Developer Utilities
Kelvin to Celsius converter
exact K−273.15, free
POST /conv/kelvin-to-celsius$0.002
Developer Utilities
Kelvin to Fahrenheit converter
exact (K−273.15)×9/5+32, free
POST /conv/kelvin-to-fahrenheit$0.002
Developer Utilities
KG to lbs converter
exact factor, free in browser
POST /conv/kg-to-lbs$0.002
Developer Utilities
Km/h to mph converter
exact factor, free in browser
POST /conv/kmh-to-mph$0.002
Developer Utilities
Knitting needle size converter
mm, US, UK metric, free
POST /conv/knitting-needle-size$0.002
Developer Utilities
Knots to meters per second
exact factor, free in browser
POST /conv/knots-to-meters-per-second$0.002