Eigenstate Labs
Eigenstate Labs
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Instruments

Every instrument in one place, grouped by subject. Filter by subject or task to find the one you need.

Statistics

Significance and A/B testing, power and sample size, confidence intervals, effect sizes, and a chooser that routes you to the right test.

statistics

Confidence Interval Calculator

Calculate Wilson, exact, Wald, and mean confidence intervals with the method and assumptions shown.
statistics

A/B Test Calculator

Compare two conversion rates or two means with a named frequentist test, effect size, and confidence interval.
statistics

Normal Distribution Calculator: Curve, Area, and Inverse

Draw a normal distribution curve and read the area below, above, between, or outside your values, with an inverse mode that finds x from a probability or percentile.
statistics

Power and Sample Size Calculator

Plan sample size, power, or effect size for two proportions or two independent means.
statistics

Minimum Detectable Effect Calculator

Estimate the smallest conversion-rate lift an A/B test plan can reliably detect.
statistics

Bayesian A/B Test Calculator

Compare two conversion variants with posterior probability under a visible beta prior.
statistics

t-Test Calculator: One-Sample, Two-Sample, Welch, and Paired

Run one-sample, two-sample (Student or Welch), and paired t-tests from raw data or summary stats. Returns the t statistic, df, exact p-value, confidence interval, and Cohen's d.
statistics

Effect Size Calculator

Convert Cohen's d, r, odds ratio, eta-squared, and Cohen's f with assumptions shown.
statistics

Error Propagation

Propagate measurement uncertainty for common operations or a typed formula.
statistics

Fisher's Exact Test

Run an exact fixed-margin 2 by 2 count test with odds ratio, p-value, and support table.
statistics

Meta-Analysis Calculator and Forest Plot Generator

Combine several studies into one estimate and draw the forest plot.
statistics

Chi-Square Test Calculator: Independence and Goodness of Fit

Chi-square test of independence or goodness of fit on any size table, with the expected-count table, each cell's contribution, degrees of freedom, the p-value, and Cramér's V.
statistics

Z-Score Calculator: Single Value, Data Set, and Percentile

Compute a z-score with z = (x - mu)/sigma for one value or a whole data set, and convert between z-scores and percentiles. Population SD by default, sample SD one toggle away, method shown.
statistics

Mann-Whitney U Test Calculator

Compare two independent samples with ranks, exact or asymptotic p-values, and effect sizes.
statistics

Two-Way ANOVA Calculator: Full Table, F, and p-Value

Run a two-way or one-way ANOVA in your browser: sums of squares, df, mean squares, F, and p for every effect, with the balanced-design and interaction conventions stated on the page.
statistics

Cohen's Kappa Calculator

Calculate unweighted Cohen kappa from a square two-rater agreement table.
statistics

Cronbach's Alpha Calculator

Estimate raw Cronbach alpha from complete item response data with alpha if item deleted.
statistics

Standard Deviation Calculator: Mean, Median, and Five-Number Summary

Paste one list of numbers to compute mean, median, mode, variance, standard deviation, five-number summary, quartiles, IQR, range, and coefficient of variation, with a sample or population toggle.
statistics

Expected Value Calculator: Variance and Standard Deviation

Enter outcomes and probabilities to get the expected value, variance, and standard deviation of a discrete distribution, with a probability check that shows the running sum and one-click normalize.
statistics

Monty Hall Simulator

Simulate stay and switch strategies under the classic host-knows Monty Hall rules.
statistics

Birthday Paradox Simulator

Birthday paradox calculator: the exact probability of a shared birthday in a group of n, with a repeated simulation that converges on the exact value.
statistics

Coefficient of Correlation Calculator

Paste two columns to get Pearson's r or Spearman's rank correlation, with r-squared, the sample size, and a significance test on r.
statistics

Bayes Theorem Calculator: Base Rates and Diagnostic Testing

Use base rate, sensitivity, and specificity to see posterior probability through natural frequencies.
statistics

CSV/JSON Column Stats

Convert CSV and JSON locally, preview rows, and compute descriptive statistics for numeric columns.
statistics

Linear Regression Calculator: Line of Best Fit, r, R², Standard Error

Fit a least-squares line to paired data, or run multiple regression on several predictors. Reports the equation, slope, intercept, r, r², the standard error of the estimate, and a scatter plot.
statistics

Simpson's Paradox Simulator

Edit subgroup counts and see how aggregate rates can reverse the within-group pattern.
statistics

Standard Error in Google Sheets

Use the Google Sheets formula for standard error and check a sample through the canonical column-stats logic.
statistics

Berkson's Paradox Simulator

Filter independent traits on a shared selection rule and see the selected-sample association emerge.
statistics

P-value in Excel

Use Excel T.TEST for a two-tailed unequal-variance t-test and compare a worked example to the canonical A/B test logic.
statistics

Z Score Table: Positive and Negative

Read positive and negative z score tables where every body value is P(Z ≤ z), the area to the left of z. Type a z to highlight its exact cell or print a clean full page.
statistics

Binomial Distribution Calculator: PMF, CDF, Table, and Inverse

Compute binomial probabilities for any comparison, read the complete k table, get the bracketed inverse with both attained probabilities, and see the normal and Poisson approximation error.
statistics

Poisson Distribution Calculator: PMF, CDF, Table, and Inverse

Compute Poisson probabilities for any comparison, read the complete k table around lambda, get the bracketed inverse with both attained probabilities, and see the normal approximation error.
statistics

T Table: Student's t Distribution Critical Values

The full Student's t table, degrees of freedom 1 to 1000 plus the normal limit, with one-tailed alpha, two-tailed alpha and confidence on every column header.
statistics

Chi-Square Table: Critical Values by Degrees of Freedom

The full chi-square table, degrees of freedom 1 to 1000, with both tails printed and every column header showing cumulative probability, right-tail area and left-tail area.
statistics

F Table: F Distribution Critical Values

Six complete F tables, one for each significance level from 0.10 down to 0.001, with numerator degrees of freedom to infinity and denominator degrees of freedom to 500 and infinity.
statistics

Critical Value Calculator: t, z, F, and Chi-Square

Find the critical value for a t, z, F, or chi-square test at any alpha, with one-tailed and two-tailed handling and the tail probability shown.
statistics

Central Limit Theorem Simulator: Sampling Distribution Calculator

Draw repeated samples from ten populations, compare two sample sizes or statistics, and read simulated values beside exact theory.
statistics

Bootstrap Confidence Interval Calculator: Resampling Simulator

Paste one or two samples, build a bootstrap distribution, and compare percentile, basic, t with bootstrap SE, and BCa intervals.
statistics

Causal DAG Builder

Build a causal DAG, choose an exposure and outcome, inspect backdoor paths, and find every minimal sufficient adjustment set in your browser.
statistics

Principal Component Analysis: PCA Calculator

Run PCA on pasted data: eigenvalues, explained variance, eigenvectors and loadings, scores, a scree plot with parallel analysis, and a biplot whose scaling convention is stated on the plot.

Chemistry

Equation balancing, stoichiometry, molar mass, solutions and dilutions, pH, and the gas laws.

chemistry

Chemical Equation Balancer

Balance any chemical equation exactly, then assign oxidation states by the standard priority rules, with worked examples for peroxides, OF2, and Fe3O4.
chemistry

Molar Mass Calculator

Convert moles to grams and grams to moles straight from a chemical formula. The molar mass is computed for you from sourced NIST/CIAAW atomic weights, with the particle count.
chemistry

Stoichiometry Calculator

Balance any equation, then read the mole ratio of any two species as raw, simplest, and decimal, and find the limiting reactant, theoretical yield, and percent yield.
chemistry

Dilution Calculator

Solve C1V1 = C2V2 for stock concentration, stock volume, final concentration, or final volume.
chemistry

Molarity and Molality Calculator

Calculate molarity, molality, or density-based conversions with explicit solution and solvent denominators.
chemistry

pH Calculator: pH, pOH, and Buffers

Convert pH, pOH, hydronium, and hydroxide, solve buffer pH by Henderson-Hasselbalch, and get weak acid or base pH from Ka or Kb with the exact quadratic root and 5% rule check at 25 deg C.
chemistry

Ideal Gas Law and Boyle's Law Calculator

Solve PV = nRT and Boyle's law (P₁V₁ = P₂V₂) for any unknown. One shared unit per pair, worked steps, absolute pressure, and ideal-gas warnings.
chemistry

Empirical Formula Calculator

Convert percent composition or masses into empirical and molecular formulas with a transparent mole-ratio table.
chemistry

Titration Calculator: Solve for Molarity, Volume, or Moles

Solve an acid-base titration for an unknown molarity, volume, or moles at the equivalence point, with polyprotic acids and bases handled through an explicit acid-to-base mole ratio.
chemistry

Specific Heat Calculator: Solve for Any Variable

Solve q = mcΔT for heat, mass, specific heat, or temperature change.
chemistry

Hess's Law Calculator: Sum Steps or Formation Enthalpies

Reaction enthalpy by summing steps, or subtracting standard formation enthalpies.
chemistry

Activation Energy Calculator: Arrhenius Ea From Two Points or a Plot

Activation energy from two rate constants, one point, or an Arrhenius plot.

Physics

Kinematics, circuits, optics, radioactive decay, spectroscopy, and simulators for wave interference, the double pendulum, and the kinetic theory of gases.

physics

Kinematics Calculator

Solve one-dimensional constant-acceleration motion from displacement, velocity, acceleration, and time with the equation used shown.
physics

Projectile Motion Calculator: Range, Height, and Trajectory Plot

Range, maximum height, and time of flight for 2D projectile motion, plotted.
physics

Frequency to Wavelength Calculator: Exact Speed of Light

Frequency to wavelength with the exact speed of light, plus photon energy.
physics

Ohm's Law Calculator

Solve voltage, current, resistance, and power for resistive circuit magnitudes, with formulas and consistency checks.
physics

Buoyancy Calculator: Buoyant Force, Float or Sink, and Fraction Submerged

Solve buoyant force from Archimedes' principle F = ρ·V·g, get a float or sink verdict from densities, and find the fraction submerged, with a sourced fluid density table.
physics

Hooke's Law Calculator: Spring Constant and Elastic Energy

Solve Hooke's law F = -kx for force, spring constant, or displacement, plus elastic energy U = (1/2)kx^2. SI and imperial units, signed restoring force, and the sign convention named.
physics

Lens and Mirror Equation Calculator

Solve thin-lens and spherical-mirror image distances with the real-is-positive Gaussian sign convention stated.
physics

Double Slit Experiment and Wave Interference Simulator

Exact fringe positions and an intensity profile with its diffraction envelope shown separately.
physics

Half-Life Decay Calculator

Solve first-order exponential decay from initial amount, remaining amount, half-life, or elapsed time with a step schedule.
physics

Kinetic Theory of Gases Simulator: Maxwell-Boltzmann Distribution

A two-dimensional hard-disk gas that derives its speed distribution from collisions.
physics

Beer-Lambert Law Calculator

Solve decadic absorbance, molar absorptivity, path length, concentration, and transmittance for a one-species optical sample.
physics

Momentum Calculator

Calculate momentum p = mv, impulse J = FΔt, and the final velocities of a 1D collision from a coefficient of restitution. Signed convention and kinetic energy lost shown.
physics

Work Calculator (Physics): Work, Energy, and Power

Work, energy, and power in one calculator: work (W = F d cos θ), power, kinetic energy, gravitational PE, and the work-energy theorem, each with its formula and convention shown.
physics

Double Pendulum Simulator: Equations of Motion, Energy, and Chaos

Four integrators on one double pendulum, each with its own energy error.

Biology

Genetics and sequence tools: Punnett squares, Hardy-Weinberg, codon translation, and GC content.

biology

Punnett Square Calculator

Build monohybrid, dihybrid, and trihybrid Punnett squares plus ABO blood type and X-linked crosses, with reduced genotypic and phenotypic ratios, gametes, and every genetic convention named.
biology

DNA Protein Translator and ORF Finder

Find open reading frames across all six frames, translate DNA or RNA with the NCBI Standard Code, and compute oligo melting temperature and GC content.
biology

Hardy-Weinberg Calculator

Calculate Hardy-Weinberg allele and genotype frequencies from counts, then run a chi-square goodness-of-fit test with degrees of freedom, an exact p-value, and a reject or fail-to-reject verdict.

Math

Significant figures, scientific notation, dimensional analysis, printable graph paper, function graphing, and a visual explanation of eigenvectors and PCA.

math

Eigenvectors and PCA: Explained Visually

Rotate a line until the spread along it is greatest, watch the perpendicular error fall by the same amount, and see that the direction you found is the top eigenvector of the covariance matrix.
math

Sig Fig Calculator

Count and round significant figures from the typed number, including decimal zeros, exact numbers, and scientific notation.
math

Scientific Notation Converter

Convert decimal, scientific, and E notation while preserving reported trailing zeros and showing engineering notation.
math

Dimensional Analysis Calculator

Convert units with a factor-label trace, exact conversion-factor notes, and dimension mismatch checks.
math

Pressure Unit Converter

Convert a pressure across eleven units at once, with exact NIST factors.
math

Printable Graph Paper

Generate printable square, dot, isometric, polar, and coordinate-plane graph paper with physical spacing and calibration bars.
math

Ratio Simplifier: Reduce Any Ratio to Lowest Terms

Reduce any ratio to lowest terms by GCD, including three-term ratios, decimals, fractions, negatives, and terms in different units.
math

Free Math Worksheets: Printable Drills with Answer Key

Generate reproducible printable arithmetic drill worksheets with answer keys, seeds, and print calibration.
math

Number to Words Converter: Spell Out Any Number in English

Spell any number out in English words with short scale, hyphenation, American or British "and", decimals, negatives, ordinals, and US check writing named on the page. Reverse parser included.
math

Function Grapher

Plot up to five real-valued functions, inspect how each expression was parsed, and export a clean graph in your browser.

Notation

Plain-English decoders for math, statistics, and science symbols, plus a copy-paste symbol keyboard.

notation

Math and Science Symbols

Look up what a math, statistics, or science symbol means, how to say it, and which field the meaning belongs to.
notation

Physics and Chemistry Symbols

Look up common physics and chemistry symbols with field, context, unit, formula, Unicode, LaTeX, and HTML entity.
notation

Copy and Paste Symbols: Math, Statistics, Physics, Chemistry

Copy math, statistics, physics, and chemistry symbols with Unicode, LaTeX, and HTML entity metadata.

Academic writing

Citation formatting, APA results sentences, and printable study aids.

writing

Citation Generator

Generate APA, MLA, and Chicago references with local CSL styles and citeproc.
writing

Results Sentence Formatter

Report statistics results in APA style: t-test, ANOVA, correlation, chi-square, and regression, each formatted as a sentence you can paste.
writing

Study Guide Maker: Sections, Key Terms, and a Self-Quiz

Organize your own course notes into a printable study guide: structured sections, a key term and definition table, a summary, and a self-quiz, with clean CSV, Anki, and Quizlet exports.
writing

Flashcard Maker from CSV, Excel, Google Sheets, or PDF Text

Make printable double-sided flashcards from a CSV or TSV file, rows pasted from Excel or Google Sheets, a pipe-delimited list, or text copied from a PDF. Study in the browser and export for Anki.
writing

Quiz Maker

Multiple choice quiz maker that grades itself. Author questions, take the test on screen or print it, and export an answer key. Your quiz stays in your browser.