Math & statistics tools
Calculators, statistics, unit conversion and number crunching — instant results, no spreadsheet needed.
Adjacency Matrix Converter
Convert a graph between edge list, adjacency matrix, and incidence matrix — directed or undirected, weighted or not. Free, private, runs in your browser.
Age Calculator
Calculate your exact age from your date of birth — years, months and days, next birthday countdown and total days lived. Free, private, in-browser.
Normalize Audio Loudness
Level any audio file to a standard loudness (LUFS) right in your browser — -14 for Spotify/YouTube, -16 for podcasts. Runs locally, nothing is uploaded, free.
Bitwise Calculator
Bitwise calculator: AND, OR, XOR, NOT, shifts, rotates and popcount on 8–64-bit integers in binary, hex, octal or decimal. Free, private, in your browser.
Bollinger Bands calculator
Compute Bollinger Bands (SMA plus/minus standard deviations) for a price series, plus %B and bandwidth, in your browser. Free, private, no upload.
Boxplot Chart Generator
Paste values or grouped CSV data and render a box-and-whisker SVG with quartiles, whiskers, mean markers, notches, outliers, and summary stats.
CAGR Calculator
Paste a series of values and get the compound annual growth rate, total growth, the multiple, doubling time and a period-by-period growth table.
Free Online Calculator
Evaluate any arithmetic expression instantly in your browser. Supports +, −, ×, ÷, parentheses and functions. No sign-up, runs offline.
Cartesian Product Generator
Generate every combination across 2-4 lists (sizes x colors x materials) — or just count them. Paste spreadsheet cells, pick any separator, output lines, CSV, JSON.
Analyze a Chat or IRC Log
Paste an IRC or chat log and get stats in your browser: who talked most, activity by hour and weekday, top words, links shared, and joins/parts/quits.
Checksum Calculator
Compute and verify CRC-32, CRC-32C, CRC-16, or CRC-8 checksums for text, hex, or base64 bytes, with hex or decimal output.
Chi-square test
Run Pearson's chi-square test online: goodness-of-fit or contingency-table independence with statistic, df, p-value and Cramér's V. Free, in-browser, no upload.
CIDR Calculator
CIDR calculator: get network address, broadcast, netmask, wildcard, usable host range and host count for any IPv4 or IPv6 prefix. Free, private, in-browser.
Column Math
Element-wise math on two columns of numbers — add, subtract, multiply, or divide two lists row by row in your browser. Free, private, no sign-up.
Compound Interest Calculator
Compute savings future value with compound interest, optional deposits, APY, total interest and a year-by-year schedule.
Correlated sample generator
Generate multivariate-normal sample data from a covariance or correlation matrix, with seeded CSV, TSV, JSON or stats output.
Critical Path Method Calculator
Find the critical path, project duration, earliest/latest start & finish, and slack from a task list — with PERT three-point estimates. Runs in your browser.
CSV stats
Compute per-column count, distinct, min, max, mean and sum for a CSV, in your browser. Free, private, no upload.
Build a Pareto cumulative percentage table
Sort label/value rows and add percent of total, cumulative sum, cumulative percent, running count, vital-few labels, and a text Pareto chart.
Cumulative Sum Calculator
Get the running total (prefix sum) of a list of numbers in your browser, with optional running average, min, and max at each step. Free, private, no sign-up.
Data Normalizer
Normalize CSV columns with min-max, z-score, or robust (median/IQR) scaling. Pick columns and delimiter. Runs entirely in your browser, free — nothing uploaded.
Debt Payoff Planner
Plan how to pay off multiple debts with the snowball or avalanche method. See your debt-free date, total interest, payoff order and the savings from an extra payment.
Descriptive statistics
Compute mean, median, mode, variance, standard deviation, quartiles, min and max for a list of numbers, in your browser. Free, private, no upload.
Document-Term Matrix Builder
Turn pasted documents into a document-term matrix. Export CSV, TSV, or JSON bag-of-words counts with binary weighting, n-grams, min document frequency, and feature caps.
eGFR Calculator
Estimate your eGFR (kidney filtration rate) from serum creatinine, age and sex with the race-free CKD-EPI 2021 equation. mg/dL or µmol/L, KDIGO stage. In your browser.
Shannon entropy calculator
Measure Shannon entropy locally: bits per character, byte, word, or line, with total information and frequency tables.
Smooth a series with an exponentially weighted moving average
Smooth a numeric series with an EWMA. Set alpha, span, half-life or center of mass, auto-fit alpha, forecast ahead, and export JSON, CSV or SVG.
First differences and period-over-period deltas
Paste a number series and get first differences, second differences, or period-over-period change as an absolute delta, percent, ratio, or log difference.
Frequency distribution
Build a character, byte, or n-gram frequency table from text or hex, with counts and percentages, ranked most to least frequent — in your browser. Nothing is uploaded.
Geometry Calculator
Geometry calculator for area, perimeter, surface area and volume — squares, triangles, circles, spheres, cylinders, cones and more. Free, private, in-browser.
Grade to GPA Parser
Paste letter grades, credits, and weighted-course tags to calculate GPA on a 4.0, 4.3, 5.0, or custom scale.
Graph Algorithms
Run graph algorithms on your own edge list — BFS, DFS, Dijkstra shortest path, topological sort, and cycle detection. Free, private, in your browser.
Histogram Bin Calculator
Work out how many bins a histogram needs. Compare Sturges, Scott, Freedman-Diaconis, Rice and square-root, then get the bin edges, counts and percentages.
Histogram Chart Maker
Paste a list of numbers and render an SVG histogram. Auto bin rules or an explicit bin count/width, count, percent, density or cumulative bars, mean and median markers.
Import & Dependency Graph Extractor
Paste JS, Python, Rust, or Go source and get an import graph with file edges, external deps, dependents, orphans, leaves, and cycles.
IQR Outlier Trimmer
Drop the CSV rows outside Q1-k*IQR to Q3+k*IQR on a column you choose. Adjustable k, winsorize or flag instead, quartile stats. Free, in-browser, no upload.
JSON entity normalizer
Normalize deeply nested JSON into id-keyed entity tables plus a result id, using a compact entity schema and deterministic local WASM.
JSON to Graph
Turn JSON into a node-link graph as Mermaid flowchart or Graphviz DOT. Collapse deep branches, cap arrays and generate paste-ready diagram source in your browser.
JSONL stats
Summarize JSON Lines records: record count, per-key coverage, value-type distribution, distinct counts, samples, and numeric/string stats.
Log return calculator
Paste a price series and get continuously compounded log returns per period, cumulative and total log return, volatility, and annualized figures as text, CSV or JSON.
MACD Calculator
Compute the MACD indicator from any price series — MACD line, signal line and histogram, with configurable 12/26/9 EMA periods. Free, private, in-browser.
Molecular Weight Calculator
Compute molar mass, monoisotopic mass, atom counts, and elemental percent composition from a chemical formula. Supports groups and hydrate dot notation.
Mortgage Calculator
Estimate your monthly mortgage payment — principal, interest, property tax, insurance and HOA — plus total interest, total cost and how extra payments shorten the term.
Moving Average Calculator
Calculate simple, exponential and weighted moving averages (SMA, EMA, WMA) over any number series with your chosen window. Free, private, in-browser.
NDJSON to matrix
Turn NDJSON / JSON Lines records into one aligned table: unified columns from dotted paths, chosen fill for missing cells, CSV, TSV, matrix or JSON out.
Outlier detector
Find outliers in a list of numbers using the z-score, modified z-score (MAD) and IQR (Tukey's fences) methods, in your browser. Free, private, no upload.
Normalize counts into per-capita rates
Paste label, count and population rows and get population-adjusted rates per capita, per 1,000, per 100,000 or a custom base.
Percent difference between two numbers
Compare two numbers: absolute difference, symmetric percentage difference, and percent change in both directions. Runs in your browser, nothing uploaded.
Percentage Calculator
Free percentage calculator: what is P% of X, what percent X is of Y, percent increase or decrease, and share of a total. Private, runs in your browser.
Rent Affordability Calculator
Work out affordable rent from income using the 30% rule or a custom ratio, with debts, gross-vs-net handling, guideline ranges, and money left over.
Rent vs Buy Calculator
Should you rent or buy a home? Run the invest-the-difference net-worth race over your time horizon and get a break-even year and a buy/rent verdict.
Round Decimals in a CSV
Round the numeric columns of a CSV to N decimal places in your browser. Pick a rounding mode (half-up, banker's, ceil, floor, truncate). Free, no upload.
Round to Nearest Multiple
Round CSV numbers to the nearest multiple of any step — 0.25, 0.05, 5, 100, 1000. Pick nearest, up, down, or banker's ties. Browser-only, no upload.
RSI calculator
Calculate Wilder's Relative Strength Index (RSI) from pasted closing prices with configurable period and overbought/oversold thresholds. Runs locally in your browser.
Salary Converter
Convert pay between hourly, daily, weekly, biweekly, monthly and annual figures. Set your hours per week and weeks per year — all six rates at once, free and in-browser.
Stepwise feature selection for regression
Run forward, backward, or bidirectional stepwise OLS regression on a numeric table to choose predictors by AIC, BIC, AICc, or p-value thresholds.
TDEE Calculator
Estimate your BMR and total daily energy expenditure from age, sex, weight, height and activity, with calorie goals, BMI and all activity levels.
Time series generator
Generate deterministic synthetic time-series CSV, TSV, JSON or NDJSON with configurable trend, seasonality, noise, missing values and outliers.
Timesheet Calculator
Paste a work log of start–stop times tagged by project and get total hours plus billable amounts with rates, rounding and overnight shifts.
Unit Converter
Convert between units of length, mass, temperature, volume, area, speed, data size, and time — instantly in your browser. Names and symbols accepted. Nothing is uploaded.
Normalize vCard Contacts
Normalize vCard address books locally: lowercase emails, format valid phone numbers, tidy names, and preserve custom fields.
YouTube Takeout stats
Parse Google/YouTube Takeout watch-history JSON or HTML into top channels, repeated videos, monthly trends, weekdays, hours, streaks, CSV, and JSON.
Z-Score Calculator
Turn raw scores into z-scores with percentiles and normal-curve probabilities, invert them, find critical values, or standardize a pasted dataset.
Z-Score Normalize
Standardize a list of numbers with z-score, min-max, max-abs, or robust median/IQR scaling. Population or sample standard deviation, private and browser-local.