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
Optical density calculator
absorbance from I0 and I
POST /phys/optical-density$0.002Developer Utilities
Parallel capacitor calculator
equivalent C in farads
POST /phys/parallel-capacitor$0.002Developer Utilities
Parallel inductors calculator
equivalent L in henries, free
POST /phys/parallel-inductors$0.002Developer Utilities
Particle velocity calculator
v from kinetic energy and mass
POST /phys/particles-velocity$0.002Developer Utilities
Performance coefficient calculator
COP = Q/W fridge & heat pump
POST /phys/performance-coefficient$0.002Developer Utilities
Photoelectric effect calculator
K_max = hf − φ from frequency
POST /phys/photoelectric-effect$0.002Developer Utilities
Photon energy calculator
E=hf=hc/λ in joules, free
POST /phys/photon-energy$0.002Developer Utilities
Piston force calculator
F from pressure and bore
POST /phys/piston-force$0.002Developer Utilities
Piston speed calculator
mean speed from stroke and RPM, free
POST /phys/piston-speed$0.002Developer Utilities
Pneumatic cylinder force calculator
extension force in N
POST /phys/pneumatic-cylinder-force$0.002Developer Utilities
Polar moment of inertia calculator
J = πd⁴/32 from diameter
POST /phys/polar-moment$0.002Developer Utilities
Pounds per minute converter
lb/min to kg/s, free
POST /phys/pounds-per-minute$0.002Developer Utilities
Pounds per square inch converter
psi to Pa, bar and atm, free
POST /phys/pounds-per-square-inch$0.002Developer Utilities
Prandtl-Meyer expansion calculator
angle and Mach from M, γ
POST /phys/prandtl-meyer-expansion$0.002Developer Utilities
Principal stress calculator
both σ1 and σ2 from plane stress
POST /phys/principal-stress$0.002Developer Utilities
Projectile motion calculator
range, max height, flight time
POST /phys/projectile-motion$0.002Developer Utilities
Pulley calculator
mechanical advantage, tension, pulling force
POST /phys/pulley$0.002Developer Utilities
Quantum number calculator
n, l, ml, ms and orbital capacity
POST /phys/quantum-number$0.002Developer Utilities
Projectile motion range calculator
speed, angle, gravity
POST /phys/range-projectile-motion$0.002Developer Utilities
RC circuit calculator
capacitor voltage over time, free
POST /phys/rc-circuit$0.002Developer Utilities
Reaction time calculator
driver reaction distance from speed
POST /phys/reaction-time$0.002Developer Utilities
Refrigerant capillary tube calculator
required tube length
POST /phys/refrigerant-capillary-tube$0.002Developer Utilities
Relativistic kinetic energy calculator
KE=(γ-1)mc² in joules
POST /phys/relativistic-ke$0.002Developer Utilities
Resistor wattage calculator
min rating from P=I²R, free
POST /phys/resistor-wattage$0.002Developer Utilities
RLC circuit calculator
f0, Z, and Q from R, L, C, free
POST /phys/rlc-circuit$0.002Developer Utilities
RLC impedance calculator
|Z| and phase from R, L, C, f
POST /phys/rlc-impedance$0.002Developer Utilities
RMS speed calculator
v_rms from T and molar mass (m/s)
POST /phys/rms-speed$0.002Developer Utilities
Rotational stiffness calculator
κ = GJ/L in N·m/rad, free
POST /phys/rotational-stiffness$0.002Developer Utilities
Rydberg equation calculator
hydrogen emission wavelength
POST /phys/rydberg-equation$0.002Developer Utilities
Section modulus calculator
elastic S = I/c from I and fiber distance
POST /phys/section-modulus$0.002Developer Utilities
Shaft size calculator
min diameter from torque and shear
POST /phys/shaft-size$0.002Developer Utilities
Shear modulus calculator
G = τ/γ in pascals, free
POST /phys/shear-modulus$0.002Developer Utilities
Shear wave velocity calculator
vs = √(G/ρ) in m/s, free
POST /phys/shear-wave-velocity$0.002Developer Utilities
Simple harmonic motion calculator
displacement x=A cos(ωt+φ)
POST /phys/simple-harmonic-motion$0.002Developer Utilities
Simple pendulum calculator
T = 2π√(L/g) period from L and g
POST /phys/simple-pendulum$0.002Developer Utilities
Slenderness ratio calculator
column λ = L/r from length and r
POST /phys/slenderness-ratio$0.002Developer Utilities
Sound wavelength calculator
λ = v/f from frequency
POST /phys/sound-wavelength$0.002Developer Utilities
Space travel time dilation
Lorentz factor from v/c, free
POST /phys/space-travel$0.002Developer Utilities
Specific gravity calculator
SG = ρ / ρ_ref, dimensionless
POST /phys/specific-gravity$0.002Developer Utilities
Speed of sound in solids
bar velocity v = √(E/ρ)
POST /phys/speed-sound-solids$0.002Developer Utilities
Speeds and feeds calculator
spindle RPM and feed per minute
POST /phys/speeds-and-feeds$0.002Developer Utilities
Spring calculator
restoring force F=-kx in newtons
POST /phys/spring$0.002Developer Utilities
Stefan-Boltzmann law
black-body radiated power P = σAT⁴
POST /phys/stefan-boltzmann-law$0.002Developer Utilities
Stokes' law calculator
settling velocity of a small sphere
POST /phys/stokes-law$0.002Developer Utilities
Stopping distance calculator
reaction plus braking in metres
POST /phys/stopping-distance$0.002Developer Utilities
Sunset time calculator
local hours from latitude and declination
POST /phys/sunset$0.002Developer Utilities
SUVAT calculator
final velocity or displacement from u, a, t
POST /phys/suvat$0.002Developer Utilities
Telescope field of view
true FOV from AFOV and magnification
POST /phys/telescope-field-of-view$0.002Developer Utilities
Thermal energy calculator
Q=mcΔT in joules from mass, c, ΔT
POST /phys/thermal-energy$0.002Developer Utilities
Thermal expansion calculator
ΔL = L₀·α·ΔT, free
POST /phys/thermal-expansion$0.002Developer Utilities
Thermal resistance calculator
R = L/(kA) in K/W, free
POST /phys/thermal-resistance$0.002Developer Utilities
Thin lens equation
image distance from f and object distance
POST /phys/thin-lens-equation$0.002Developer Utilities
Thrust-to-weight calculator
TWR = F/W for rockets, free
POST /phys/thrust-weight$0.002Developer Utilities
Time dilation calculator
dilated time from proper time and velocity
POST /phys/time-dilation$0.002Developer Utilities
Toilet paper race mass moment of inertia
I = ½m(ri²+ro²)
POST /phys/toilet-paper-race-mass-moment-inertia$0.002Developer Utilities
Torsional spring calculator
κ = E d⁴ / (64 D N), N·mm/rad
POST /phys/torsional-spring$0.002Developer Utilities
Torsional stiffness calculator
κ = GJ/L in N·m/rad, free
POST /phys/torsional-stiffness$0.002Developer Utilities
Transmission coefficient calculator
power T from η₁, η₂
POST /phys/transmission$0.002Developer Utilities
True strain calculator
ε_t = ln(1+ε) from engineering strain
POST /phys/true-strain$0.002Developer Utilities
Barrel twist rate calculator
Greenhill formula, one turn per inch
POST /phys/twist-rate$0.002