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
At least one event probability calculator
independent trials
POST /stat/at-least-one$0.002Developer Utilities
Coin toss streak probability calculator
chance of consecutive heads
POST /stat/coin-streak$0.002Developer Utilities
Complement probability calculator
P(not A) = 1 − P(A), free
POST /stat/complement-probability$0.002Developer Utilities
Expected payoff calculator for games and gambles
POST /stat/expected-payoff$0.002Developer Utilities
Lottery jackpot odds calculator
match all numbers, free
POST /stat/lottery-odds$0.002Developer Utilities
Marginal probability calculator
joint table to P(X) or P(Y)
POST /stat/marginal-probability$0.002Developer Utilities
Mutually Exclusive Events Checker
Test Two Probabilities
POST /stat/mutually-exclusive-check$0.002Developer Utilities
Binomial Mean and Variance Calculator
POST /stat/binomial-mean-variance$0.002Developer Utilities
Expected value of a dice roll
n dice × s sides average total
POST /stat/expected-dice-roll$0.002Developer Utilities
Geometric CDF calculator
probability of success within k trials
POST /stat/geometric-cdf$0.002Developer Utilities
Poisson at least probability calculator
P(X ≥ k) from rate λ
POST /stat/poisson-at-least$0.002Developer Utilities
Poisson PMF calculator
P(X=k) = e^{−λ} λ^k / k!
POST /stat/poisson-pmf$0.002Developer Utilities
Probability of Neither Event Calculator
Find P(Neither A nor B)
POST /stat/probability-neither$0.002Developer Utilities
Two-stage probability tree calculator
calculate every path
POST /stat/probability-tree-two-stage$0.002Developer Utilities
Discrete RV standard deviation
σ from values and probabilities
POST /stat/std-dev-discrete-rv$0.002Developer Utilities
Continuous uniform CDF calculator
cumulative probability
POST /stat/continuous-uniform-cdf$0.002Developer Utilities
Negative Binomial Mean and Variance Calculator
POST /stat/negative-binomial-mean-variance$0.002Developer Utilities
Normal distribution CDF calculator
Φ(x) from mean and σ
POST /stat/normal-cdf$0.002Developer Utilities
Z-score from normal value calculator
z = (x − μ) / σ, free
POST /stat/normal-z-from-x$0.002Developer Utilities
Percentile to z-score calculator
inverse normal distribution
POST /stat/percentile-to-z$0.002Developer Utilities
Confidence Interval for Variance Calculator
POST /stat/ci-variance$0.002Developer Utilities
Exponential mean and variance calculator
μ, σ², σ from rate λ
POST /stat/exponential-mean-variance$0.002Developer Utilities
F Critical Value Calculator
Numerator and Denominator Degrees of Freedom
POST /stat/f-critical-value$0.002Developer Utilities
Gamma distribution PDF calculator
shape, rate and x
POST /stat/gamma-pdf$0.002Developer Utilities
Probability distribution validity checker
PMF sums to 1, no negatives
POST /stat/pmf-validity$0.002Developer Utilities
Standard normal probability calculator
area between two z bounds
POST /stat/standard-normal-probability$0.002Developer Utilities
Student t Distribution CDF Calculator
POST /stat/t-cdf$0.002Developer Utilities
Confidence interval for paired differences
t-based mean CI, free
POST /stat/ci-paired-mean$0.002Developer Utilities
Clopper-Pearson Exact Confidence Interval Calculator
POST /stat/clopper-pearson$0.002Developer Utilities
Confidence Level and Alpha Calculator
Significance and Tail Areas
POST /stat/confidence-level-alpha$0.002Developer Utilities
P-value from z-score calculator
one- or two-tailed
POST /stat/p-value-z$0.002Developer Utilities
Sample Size for a Proportion Calculator
POST /stat/sample-size-proportion$0.002Developer Utilities
Standard error of a proportion calculator
SE = √(p(1−p)/n), free
POST /stat/se-proportion$0.002Developer Utilities
One-Sample T-Test Calculator
T Statistic, Degrees of Freedom and P-Value
POST /stat/t-test-one-sample$0.002Developer Utilities
Two-tailed critical value calculator
±z from significance level α
POST /stat/two-tailed-critical$0.002Developer Utilities
Bartlett test calculator
compare variances across groups
POST /stat/bartlett-test$0.002Developer Utilities
Chi-square independence test calculator
contingency table χ², df, p-value
POST /stat/chi-square-independence$0.002Developer Utilities
Mann-Whitney U Test Calculator with P-Value
POST /stat/mann-whitney-u$0.002Developer Utilities
P-value from F statistic calculator
upper-tail F(df1, df2), free
POST /stat/p-value-f$0.002Developer Utilities
Paired t-test calculator
t statistic, df and p-value free
POST /stat/t-test-paired$0.002Developer Utilities
Absolute risk reduction calculator
compare event rates
POST /stat/absolute-risk-reduction$0.002Developer Utilities
ANOVA from group summaries
one-way F and p-value from means, SDs, n
POST /stat/anova-summary$0.002Developer Utilities
Log odds ratio calculator with standard error
POST /stat/log-odds-ratio$0.002Developer Utilities
Omega squared calculator
ANOVA effect size from sums of squares
POST /stat/omega-squared$0.002Developer Utilities
Relative risk calculator
RR from exposed and unexposed counts
POST /stat/relative-risk$0.002Developer Utilities
Cohen's h calculator
effect size for two proportions free
POST /stat/cohens-h$0.002Developer Utilities
Exponential moving average calculator
EMA with smoothing factor
POST /stat/exponential-moving-average$0.002Developer Utilities
Fisher ideal price index
geometric mean of Laspeyres and Paasche
POST /stat/fisher-price-index$0.002Developer Utilities
Gini coefficient calculator
measure inequality from 0 to 1
POST /stat/gini-coefficient$0.002Developer Utilities
Rényi entropy calculator
H_α from probabilities and order α
POST /stat/renyi-entropy$0.002Developer Utilities
Simpson Dominance Index Calculator for Species Counts
POST /stat/simpson-dominance-index$0.002Developer Utilities
Theil index calculator
measure income inequality with entropy
POST /stat/theil-index$0.002Developer Utilities
Arcsine in radians calculator
principal asin angle
POST /trig/arcsin-radians$0.002Developer Utilities
Cosine of angle in degrees calculator
find cos from any angle
POST /trig/cos-degrees$0.002Developer Utilities
Adjacent Side Calculator from Angle and Opposite Side
POST /trig/adjacent-side-from-angle$0.002Developer Utilities
Arccotangent in degrees calculator
principal arccot angle
POST /trig/arccot-degrees$0.002Developer Utilities
Arcsecant in degrees calculator
arcsec(x) principal angle free
POST /trig/arcsec-degrees$0.002Developer Utilities
Right triangle missing leg from area
other leg, hypotenuse, angles
POST /trig/right-triangle-area-leg$0.002Developer Utilities
Solve a right triangle from two legs
sides, angles and area
POST /trig/right-triangle-two-legs$0.002Developer Utilities
Secant of an Angle in Degrees Calculator
POST /trig/sec-degrees$0.002