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
Telescope true field of view calculator
TFOV = AFOV / M
POST /optics/telescope-true-field-of-view$0.002Developer Utilities
Abbe number calculator from refractive indices
POST /optics/abbe-number$0.002Developer Utilities
Camera angle of view calculator
sensor size and focal length
POST /optics/camera-angle-of-view$0.002Developer Utilities
Diffraction-limited spot size
Airy diameter (λ, f-number)
POST /optics/diffraction-limited-spot-size$0.002Developer Utilities
Prism angle of deviation calculator
incidence, emergence and apex angle
POST /optics/prism-angle-of-deviation$0.002Developer Utilities
Refractive index from speed of light
n = c/v calculator, free
POST /optics/refractive-index-from-speed$0.002Developer Utilities
Total internal reflection critical angle calculator
POST /optics/total-internal-reflection-angle$0.002Developer Utilities
Fresnel reflection at normal incidence
R from n₁, n₂, free
POST /optics/fresnel-reflection-normal$0.002Developer Utilities
Grating resolving power calculator
order times illuminated lines
POST /optics/grating-resolving-power$0.002Developer Utilities
Grating wavelength from angle calculator
POST /optics/grating-wavelength-from-angle$0.002Developer Utilities
Single-slit diffraction minima angle
θ from m, λ and a
POST /optics/single-slit-minima-angle$0.002Developer Utilities
Thin prism deviation calculator
δ = (n − 1)A, free
POST /optics/thin-prism-deviation$0.002Developer Utilities
Wavelength from double-slit fringes calculator
POST /optics/wavelength-from-double-slit$0.002Developer Utilities
Anti-reflection coating thickness calculator
quarter-wave t = λ/(4n)
POST /optics/antireflection-coating-thickness$0.002Developer Utilities
Fresnel number calculator
aperture, distance and wavelength
POST /optics/fresnel-number$0.002Developer Utilities
Michelson interferometer mirror displacement
ΔL = Nλ/2 from fringes
POST /optics/michelson-mirror-displacement$0.002Developer Utilities
Newton's rings lens radius of curvature
R from ring radius, order, λ
POST /optics/newtons-rings-lens-radius$0.002Developer Utilities
Photoelectric Threshold Wavelength Calculator
POST /optics/photoelectric-threshold-wavelength$0.002Developer Utilities
Photon Flux from Power Calculator
Photons per Second
POST /optics/photon-flux-from-power$0.002Developer Utilities
Unpolarized light through polarizer calculator
POST /optics/unpolarized-through-polarizer$0.002Developer Utilities
Wavelength from photon energy
λ = hc/E calculator
POST /optics/wavelength-from-photon-energy$0.002Developer Utilities
Exposure value from aperture and shutter calculator
POST /optics/exposure-value-from-settings$0.002Developer Utilities
Illuminance from luminous intensity
E = I / r² lux calculator, free
POST /optics/illuminance-from-intensity$0.002Developer Utilities
ISO stops difference calculator
compare camera sensitivity
POST /optics/iso-stops-difference$0.002Developer Utilities
Luminous efficacy calculator
lumens per watt from light output and power
POST /optics/luminous-efficacy$0.002Developer Utilities
Shutter speed from exposure value
t from EV and f-number
POST /optics/shutter-speed-from-ev$0.002Developer Utilities
Temperature from radiated power
inverted Stefan–Boltzmann T from P, A, ε
POST /optics/temperature-from-radiated-power$0.002Developer Utilities
Wien displacement law calculator
blackbody peak wavelength
POST /optics/wien-peak-wavelength$0.002Developer Utilities
Fiber material dispersion calculator
pulse broadening from D, Δλ, L
POST /optics/fiber-material-dispersion$0.002Developer Utilities
Fiber relative refractive index difference
Δ core/cladding
POST /optics/fiber-relative-index-difference$0.002Developer Utilities
Fiber total loss calculator
attenuation over link length
POST /optics/fiber-total-loss$0.002Developer Utilities
Flash distance from guide number
distance = GN ÷ f-number
POST /optics/flash-distance-from-guide-number$0.002Developer Utilities
Optical path length calculator
refractive index × distance
POST /optics/optical-path-length$0.002Developer Utilities
Single-mode fiber cutoff wavelength calculator
POST /optics/single-mode-cutoff-wavelength$0.002Developer Utilities
Optical etendue calculator
source area and solid angle
POST /optics/etendue$0.002Developer Utilities
IQR outlier detection calculator
flag values beyond 1.5 IQR
POST /stat/iqr-outlier-detection$0.002Developer Utilities
Median absolute deviation calculator
Find MAD online
POST /stat/median-absolute-deviation$0.002Developer Utilities
Mode of a dataset calculator
most frequent value(s), free
POST /stat/mode-value$0.002Developer Utilities
Population variance calculator
divide squared deviations by N
POST /stat/population-variance$0.002Developer Utilities
Quintile calculator
four cuts that split data into five groups
POST /stat/quintiles$0.002Developer Utilities
Standard error of the mean calculator
SEM = s/√n, free
POST /stat/standard-error-mean$0.002Developer Utilities
Winsorized Mean Calculator
Reduce the Effect of Extreme Values
POST /stat/winsorized-mean$0.002Developer Utilities
Class Width Calculator for Frequency Tables
POST /stat/class-width$0.002Developer Utilities
Cumulative Frequency Calculator for Class Counts
POST /stat/cumulative-frequency$0.002Developer Utilities
Grouped data mode calculator
interpolate the modal value
POST /stat/grouped-mode$0.002Developer Utilities
Moment coefficient of skewness calculator
third central moment
POST /stat/moment-skewness$0.002Developer Utilities
Standardized moment calculator
k-th central moment ÷ σ^k
POST /stat/standardized-moment$0.002Developer Utilities
Kendall tau correlation calculator
concordant and discordant pairs
POST /stat/kendall-tau$0.002Developer Utilities
Mean deviation about median calculator
MAD from the median, free
POST /stat/mean-deviation-median$0.002Developer Utilities
Pearson mode skewness calculator
(mean − mode) / standard deviation
POST /stat/pearson-mode-skewness$0.002Developer Utilities
Regression intercept calculator
least-squares y-intercept
POST /stat/regression-intercept$0.002Developer Utilities
Sample covariance calculator
covariance with n minus one
POST /stat/sample-covariance$0.002Developer Utilities
Scott's rule bin width calculator
optimal histogram h from σ and n
POST /stat/scott-rule$0.002Developer Utilities
Concordance correlation coefficient calculator
Lin's CCC for two series
POST /stat/concordance-correlation$0.002Developer Utilities
Cubic regression calculator
third-degree least-squares coefficients
POST /stat/cubic-regression$0.002Developer Utilities
Line of best fit calculator
slope, intercept, and predictions
POST /stat/line-of-best-fit$0.002Developer Utilities
Mean Absolute Percentage Error (MAPE) Calculator
POST /stat/mape-error$0.002Developer Utilities
Partial correlation calculator
r_xy.z from three pairwise r
POST /stat/partial-correlation$0.002Developer Utilities
Power regression calculator
fit y = a·x^b by log least squares
POST /stat/power-regression$0.002Developer Utilities
Standard error of the estimate
SEE residual size, free
POST /stat/standard-error-estimate$0.002