Statistics

Z-scores, confidence intervals, sample sizes, and more.

Z-Score Calculator

Z-score, percentile, and probability from a value, mean, and standard deviation.

Confidence Interval Calculator

Confidence interval and margin of error from sample statistics.

Sample Size Calculator

Required sample size for a survey at a given confidence and margin of error.

Correlation Coefficient Calculator

Pearson correlation coefficient (r) and R² from two data lists.

P-Value Calculator

P-value and significance from a z-statistic (one- or two-tailed).

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Mortgage Calculator

See your monthly payment, total interest, and PMI risk for any home loan.

Loan Calculator

Monthly payment, total interest, and total cost for any fixed-rate loan.

BMI Calculator

Body mass index, WHO category, and your healthy weight range.

Percentage Calculator

Percent of a number, percent one number is of another, and percent change.

JSON Formatter & Validator

Format, validate, and minify JSON with precise error messages.

Word Counter

Words, characters, sentences, paragraphs, and reading time — live.

Merge PDF

Combine several PDF files into one, in any order.

Image Compressor

Shrink image file size with a live quality preview.