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
Depth of field far limit calculator
POST /optics/depth-of-field-far$0.002Developer Utilities
Incidence angle from Snell's law calculator
solve from refraction angle
POST /optics/incidence-angle-from-snell$0.002Developer Utilities
Spherical mirror object distance calculator
from focal and image distance
POST /optics/mirror-object-distance$0.002Developer Utilities
Cauchy Dispersion Refractive Index Calculator
POST /optics/cauchy-dispersion-index$0.002Developer Utilities
Double-slit bright fringe position calculator
POST /optics/fringe-position-double-slit$0.002Developer Utilities
Relative refractive index calculator
calculate n₂ divided by n₁
POST /optics/relative-refractive-index$0.002Developer Utilities
Bright Newton's ring radius
order, wavelength and curvature
POST /optics/newtons-rings-bright-radius$0.002Developer Utilities
Thin film constructive interference calculator
film thickness
POST /optics/thin-film-constructive$0.002Developer Utilities
Bragg law interplanar spacing calculator
POST /optics/bragg-plane-spacing$0.002Developer Utilities
Coherence time calculator
convert coherence length to time
POST /optics/coherence-time$0.002Developer Utilities
Luminous Intensity from Illuminance Calculator
POST /optics/luminous-intensity-from-illuminance$0.002Developer Utilities
Stefan-Boltzmann radiant exitance calculator
blackbody M = σT⁴
POST /optics/stefan-boltzmann-exitance$0.002Developer Utilities
Work Function from Threshold Wavelength Calculator
POST /optics/work-function-from-threshold$0.002Developer Utilities
Fiber length from loss budget calculator
maximum reach
POST /optics/fiber-length-from-loss-budget$0.002Developer Utilities
Graded-index fiber mode count calculator
POST /optics/graded-index-fiber-modes$0.002Developer Utilities
Reciprocity shutter speed calculator for aperture stop changes
POST /optics/reciprocity-shutter-speed$0.002Developer Utilities
Sunny 16 rule shutter speed calculator for any film ISO
POST /optics/sunny-16-shutter-speed$0.002Developer Utilities
Radiant intensity calculator
power divided by solid angle
POST /optics/radiant-intensity-from-power$0.002Developer Utilities
Data range calculator
maximum minus minimum
POST /stat/data-range$0.002Developer Utilities
Decile calculator
find D1 through D9 from a data set
POST /stat/deciles$0.002Developer Utilities
Excess kurtosis calculator
standardized fourth central moment
POST /stat/excess-kurtosis$0.002Developer Utilities
Grubbs outlier test calculator
compute the G statistic
POST /stat/grubbs-test$0.002Developer Utilities
Midhinge calculator
average of Q1 and Q3
POST /stat/midhinge$0.002Developer Utilities
Coefficient of determination calculator
calculate R squared
POST /stat/coefficient-determination$0.002Developer Utilities
Deviation scores calculator
subtract the mean from every value
POST /stat/deviation-scores$0.002Developer Utilities
Geometric standard deviation calculator
measure multiplicative spread
POST /stat/geometric-std-dev$0.002Developer Utilities
Sturges' Rule Bin Count Calculator
POST /stat/sturges-rule$0.002Developer Utilities
Cramer's V calculator
association strength from a contingency table
POST /stat/cramers-v$0.002Developer Utilities
Polynomial regression calculator
least-squares coefficients
POST /stat/polynomial-regression$0.002Developer Utilities
Regression residuals calculator
observed minus predicted values
POST /stat/regression-residuals$0.002Developer Utilities
Kendall's W concordance calculator for ranked data
POST /stat/kendall-w$0.002Developer Utilities
Total sum of squares calculator
squared deviations from the mean
POST /stat/total-sum-squares$0.002Developer Utilities
Conditional expectation calculator
expected value given an event
POST /stat/conditional-expectation$0.002Developer Utilities
Joint probability of two events calculator
independent events
POST /stat/joint-probability-two$0.002Developer Utilities
Poker hand probability calculator
exact five-card odds
POST /stat/poker-hand-odds$0.002Developer Utilities
Binomial At Most Probability Calculator
POST /stat/binomial-at-most$0.002Developer Utilities
Geometric PMF calculator
first success on trial k
POST /stat/geometric-pmf$0.002Developer Utilities
Probability Exactly One Event Calculator
Find P(A or B, Not Both)
POST /stat/probability-exactly-one$0.002Developer Utilities
Chi-Square Critical Value Calculator
POST /stat/chi-square-critical$0.002Developer Utilities
Discrete uniform mean and variance calculator
POST /stat/discrete-uniform-mean-variance$0.002Developer Utilities
Normal probability between values calculator
POST /stat/normal-between$0.002Developer Utilities
Z-score to percentile calculator
standard normal percentile
POST /stat/z-to-percentile$0.002Developer Utilities
Confidence Interval for the Difference of Proportions Calculator
POST /stat/ci-diff-proportions$0.002Developer Utilities
F Distribution CDF Calculator
POST /stat/f-cdf$0.002Developer Utilities
Lognormal Distribution CDF Calculator
POST /stat/lognormal-cdf$0.002Developer Utilities
Confidence Interval for a Ratio of Variances Calculator
POST /stat/ci-ratio-variances$0.002Developer Utilities
Sample Size for a Mean Calculator
POST /stat/sample-size-mean$0.002Developer Utilities
Standard Error of Difference of Proportions Calculator
POST /stat/se-diff-proportions$0.002Developer Utilities
F Test for Two Variances Calculator
F Statistic and P-Value
POST /stat/f-test-variances$0.002Developer Utilities
Levene Test Calculator
Statistic and P-Value
POST /stat/levene-test$0.002Developer Utilities
Wilcoxon signed-rank test calculator
statistic and p-value
POST /stat/wilcoxon-signed-rank$0.002Developer Utilities
Two-Proportion Z-Test Calculator
POST /stat/z-test-two-proportions$0.002Developer Utilities
Eta squared calculator
variance explained from sums of squares
POST /stat/eta-squared$0.002Developer Utilities
Odds Ratio Calculator for a 2x2 Table
POST /stat/odds-ratio$0.002Developer Utilities
Weighted moving average calculator
sliding weighted mean
POST /stat/weighted-moving-average$0.002Developer Utilities
Atkinson Index Calculator for Income Inequality
POST /stat/atkinson-index$0.002Developer Utilities
Double Exponential Smoothing Calculator
Holt Forecast
POST /stat/double-exponential-smoothing$0.002Developer Utilities
Kullback-Leibler Divergence Calculator for Probability Distributions
POST /stat/kl-divergence$0.002Developer Utilities
Two-argument arctangent calculator in degrees
atan2(y, x)
POST /trig/atan2-degrees$0.002Developer Utilities
Cotangent of an angle in radians calculator
POST /trig/cot-radians$0.002