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
Bounding box union
smallest box containing two bboxes, free
POST /geo/bbox-union$0.002Developer Utilities
Concave hull approximation from point coordinates
POST /geo/concave-hull-approx$0.002Developer Utilities
Round coordinate precision
lat/lon decimal places for privacy or storage
POST /geo/coordinate-round$0.002Developer Utilities
Circular geofence check
point inside radius and margin distance
POST /geo/geofence-circle-check$0.002Developer Utilities
Grid-based point clustering
count coordinates by cell
POST /geo/point-cluster-grid$0.002Developer Utilities
Rectifying latitude calculator
geodetic φ to μ (meridian arc)
POST /geo/rectifying-latitude$0.002Developer Utilities
Decimal expansion of a fraction
with repeating part
POST /math/decimal$0.002Developer Utilities
Decimal to degrees and minutes converter
whole degrees + minutes
POST /math/decimal-to-minutes-degrees$0.002Developer Utilities
Behrmann Equal-Area Projection Calculator
POST /geo/behrmann-projection$0.002Developer Utilities
32-point compass to bearing
rose name to degrees, free
POST /geo/cardinal32-to-bearing$0.002Developer Utilities
Equidistant conic projection
lat/lon to X/Y, free
POST /geo/equidistant-conic$0.002Developer Utilities
Great-circle maximum latitude calculator using Clairaut's relation
POST /geo/great-circle-max-latitude$0.002Developer Utilities
Polygon bounding box calculator
latitude and longitude bounds
POST /geo/polygon-bounding-box$0.002Developer Utilities
Meridian radius of curvature
WGS84 M(φ) at geodetic latitude
POST /geo/radius-meridian-curvature$0.002Developer Utilities
Rhumb line midpoint calculator
find the loxodrome halfway point
POST /geo/rhumb-midpoint$0.002Developer Utilities
Determinant calculator
det(A) of a square matrix, free online
POST /math/determinant$0.002Developer Utilities
Distance off by two bearings
coastal navigation distance off landmark
POST /geo/distance-off-two-bearings$0.002Developer Utilities
Diagonal of a rectangle
instant length from width and height
POST /math/diagonal-of-rectangle$0.002Developer Utilities
Diagonalize a matrix
eigenvalues and change-of-basis P, free
POST /math/diagonalize-matrix$0.002Developer Utilities
Phase difference to path difference calculator
radians and wavelength
POST /optics/phase-to-path-difference$0.002Developer Utilities
String wave average power calculator
P = ½ μ v ω² A²
POST /optics/string-wave-average-power$0.002Developer Utilities
Wave intensity inverse square law calculator
POST /optics/wave-intensity-inverse-square$0.002Developer Utilities
Angular wave number calculator
k = 2π/λ from wavelength (m)
POST /optics/wave-number-from-wavelength$0.002Developer Utilities
Wave phase value calculator
instantaneous phase in radians
POST /optics/wave-phase-value$0.002Developer Utilities
Diameter of cone
base diameter from volume and height online
POST /math/diameter-of-cone$0.002Developer Utilities
Closed pipe fundamental frequency calculator
POST /optics/closed-pipe-fundamental$0.002Developer Utilities
Group velocity calculator
vg ≈ Δω/Δk from two (k, ω) points
POST /optics/group-velocity-finite-difference$0.002Developer Utilities
Shallow water wave speed calculator
c = sqrt(g h)
POST /optics/shallow-water-wave-speed$0.002Developer Utilities
Standing wave antinodes count calculator
nth harmonic fixed-fixed string
POST /optics/standing-wave-antinodes-count$0.002Developer Utilities
String linear density from frequency calculator
μ = T/(2Lf)²
POST /optics/string-linear-density-from-frequency$0.002Developer Utilities
String nth harmonic frequency
from wave speed and length
POST /optics/string-nth-harmonic-frequency$0.002Developer Utilities
Wave amplitude reflection coefficient calculator
R from Z1 and Z2 free
POST /optics/wave-reflection-coefficient$0.002Developer Utilities
Pipe end correction calculator
acoustic ΔL ≈ 0.6·r from tube radius
POST /optics/pipe-end-correction$0.002Developer Utilities
Resonance tube speed of sound calculator
consecutive lengths
POST /optics/resonance-tube-speed-of-sound$0.002Developer Utilities
Speed from Mach number calculator
actual speed = M × local speed of sound
POST /optics/speed-from-mach-number$0.002Developer Utilities
Speed of sound in ideal gas calculator
γ, temperature and molar mass
POST /optics/speed-of-sound-ideal-gas$0.002Developer Utilities
String frequency after tension change
f₂ = f₁√(T₂/T₁)
POST /optics/string-frequency-from-tension-change$0.002Developer Utilities
Distance for target sound level
inverse-square range from dB, free
POST /optics/distance-for-target-sound-level$0.002Developer Utilities
Sound power from power level calculator
watts from Lw (dB re 1 pW)
POST /optics/sound-power-from-power-level$0.002Developer Utilities
Specific Acoustic Impedance Calculator
Density × Sound Speed
POST /optics/specific-acoustic-impedance$0.002Developer Utilities
Average Absorption Coefficient Calculator for Rooms
POST /optics/average-absorption-coefficient$0.002Developer Utilities
Doppler effect with wind
observed frequency via effective sound speed
POST /optics/doppler-with-wind$0.002Developer Utilities
Mass law transmission loss
sound TL from surface mass & frequency
POST /optics/mass-law-transmission-loss$0.002Developer Utilities
MIDI note to frequency calculator
Hz from MIDI number (A4=440)
POST /optics/midi-note-to-frequency$0.002Developer Utilities
Schroeder frequency calculator
room modes and diffuse field
POST /optics/schroeder-frequency$0.002Developer Utilities
Semitones between frequencies calculator
equal temperament interval
POST /optics/semitones-between-frequencies$0.002Developer Utilities
Ultrasound Doppler frequency shift calculator
reflected wave
POST /optics/ultrasound-doppler-shift$0.002Developer Utilities
Combined focal length of lenses in contact calculator
POST /optics/combined-focal-lenses-contact$0.002Developer Utilities
Focal length from lens radii
thin lens f from n, R1, R2
POST /optics/focal-length-from-radii$0.002Developer Utilities
Helmholtz resonator volume calculator
V from f, A, L, c
POST /optics/helmholtz-resonator-volume$0.002Developer Utilities
Object distance thin lens calculator
do from f and di, free
POST /optics/object-distance-thin-lens$0.002Developer Utilities
Object height from magnification calculator
ho = hi / m
POST /optics/object-height-from-magnification$0.002Developer Utilities
Pythagorean tuning frequency
pure fifths from a reference pitch
POST /optics/pythagorean-tuning-frequency$0.002Developer Utilities
Sound level exponential decay calculator
SPL after time
POST /optics/sound-level-exponential-decay$0.002Developer Utilities
Wavelength of a musical note calculator
frequency to length
POST /optics/wavelength-of-musical-note$0.002Developer Utilities
Compound microscope magnification calculator
total M from L, f_o, f_e
POST /optics/compound-microscope-magnification$0.002Developer Utilities
Lens focal length in a medium calculator
POST /optics/lens-focal-length-in-medium$0.002Developer Utilities
Mirror focal length from radius
f = R/2 for spherical mirrors
POST /optics/mirror-focal-from-radius$0.002Developer Utilities
Spherical mirror image height calculator
height from magnification
POST /optics/mirror-image-height$0.002Developer Utilities
Telescope objective focal length calculator
target magnification
POST /optics/telescope-objective-focal$0.002