Free online tools

0-9

• 2-column / 3-column notes (T-chart) PDF generator.
  Create 2- or 3-column note paper (T-chart) in millimeters.

A

• Accessible Color Palette Generator.
  Build a role-based accessible palette from one approved base color, then review surface, text, accent, and button.
• Algebra Worksheet Generator.
  Create printable algebra handouts with answer keys and optional worked steps.
• Annotation paper PDF generator (comment margin).
  Create annotation paper with an adjustable comment margin and ruled, dot, or blank guides in millimeters, then print.
• Aspect Ratio Calculator.
  Simplify image or video ratios, solve a missing width or height, and preview contain, cover, and crop behavior.

B

• Base64 Encode / Decode Tool.
  Encode text to Base64, decode Base64 to text, and convert files to Base64 or data URI locally in your browser.
• Best Meeting Time Across Time Zones.
  Find the best meeting time across time zones using working-hour overlap, ranked suggestions, and a shareable.
• Beta Distribution Generator & Visualizer.
  Generate random samples from a Beta distribution and visualize the PDF and histogram.
• Bingo card generator (printable).
  Generate printable bingo cards and call lists in your browser.

C

• Calligraphy guide sheet PDF generator.
  Adjust x-height/ascender/descender ratios, slant angle (52–55°), unit lines, vertical guides, and left margin lines.
• Card deck shuffler – shuffle & draw cards.
  Shuffle a deck of playing cards and draw or deal cards in your browser.
• Chinese character grid (Tianzige / Mizhige) PDF.
  Generate Tianzige/Mizhige practice grids in millimeters.
• Clock Tools: Meeting Planner, Unix Timestamp, Timer.
  Browse clock and time tools for meeting planning, Unix timestamp conversion, military time conversion, timers, alarms.
• Color Converter.
  Convert one color between HEX, RGB, HSL, and a matching common color keyword.
• Color Difference Checker.
  Compare two colors by RGB distance and a simple perceptual ΔE76 gap, then review HEX, RGB, and HSL values in your.
• Color Harmony Generator.
  Generate analogous, complementary, triadic, or split-complementary color sets from one base color, then copy HEX, RGB.
• Color Mixer.
  Blend two colors by ratio, then inspect the mixed result in HEX, RGB, HSL, and a matching common color keyword.
• Color Palette Generator.
  Generate quick tints, shades, tones, and accent colors from one base color, then inspect HEX, RGB, and HSL values.
• Color Picker.
  Pick a color and read HEX, RGB, HSL, plus quick contrast checks against black and white.
• Color Scale Generator.
  Build a quick 5, 7, or 9-step color scale from one base color, preview each step, and copy HEX, RGB, or HSL values.
• Color Temperature Checker.
  Check whether one color reads warm, cool, or neutral, then compare a slightly warmer and cooler variation in your.
• Color Token Audit.
  Audit one token-ready color set before export.
• Color Token Diff.
  Compare two token-ready color sets role by role.
• Color Token Export Generator.
  Start from one approved brand color, then export light and dark role palettes as CSS variables, JSON tokens.
• Color Token Naming.
  Stabilize semantic, component, state, and theme token naming before audit or export.
• Color Token Preview.
  Preview light and dark tokenized UI cards before exporting CSS variables or JSON tokens.
• Column Arithmetic Worksheet Generator.
  Build printable column-arithmetic worksheets for addition, subtraction, multiplication, division, decimal.
• Compare PDFs by text – browser-only diff tool.
  Upload two PDFs, extract their text locally, and highlight differences by line or paragraph.
• Component Color Tokens.
  Turn approved role colors into component aliases such as button, card, input, nav, and badge tokens.
• Contrast Checker.
  Check contrast ratio for foreground and background colors, then see quick WCAG AA/AAA verdicts for normal.
• Cornell notes PDF generator – cue/notes/summary layout.
  Generate Cornell notes paper as SVG in millimeters.
• Crop & resize PDF pages – adjust size, margins.
  Crop and resize PDF pages in your browser.
• CSS Color Mix Generator.
  Build a ready-to-paste CSS color-mix() string from two known colors, then preview the mixed result in OKLCH or sRGB.
• CSV Column Profiler.
  Paste CSV or TSV data to inspect column types, missing values, unique counts, and next chart or stats options.

D

• Dice roller (d4 to d100, 2d6+3, PNG).
  Roll d4 to d100 or use notation like 2d6+3.
• Dice stats (odds & distribution) + PNG sharing.
  Compute odds and distributions for NdS +/- K.
• Dice tools – roller, TRPG checks, dice stats.
  Browser-only dice tools: dice roller, TRPG checks, and dice stats for odds and distributions.
• Dirichlet Distribution Generator & Visualizer.
  Generate probability vectors from a Dirichlet distribution and visualize marginals and simplex plots.
• Distribution Sampler and Histogram Tool.
  Generate random samples from common distributions, visualize histograms, review summary stats, and export CSV/JSON.
• Dot grid paper PDF generator – printable SVG in mm.
  Generate dot grid paper as an SVG in millimeters.

E

• Embed Builder — share links & iframe code.
  Create CalcBE share links and responsive iframe embeds.
• Engineering paper PDF generator.
  Generate engineering paper with 4/5/10 squares per inch converted to millimeters.
• Epoch Converter.
  Convert Unix epoch seconds or milliseconds to UTC and local time, or parse ISO 8601 dates back to timestamps.
• Event Countdown (Time Remaining).
  Show time remaining until a target date/time with an analog + digital display.

F

• Flashcard / index card PDF generator (cut guides).
  Auto-arrange 3x5, 4x6, A7, and custom index cards on one page with cut lines or crop marks, then print a precise.
• Float Inspector Tool.
  Inspect IEEE 754 bit layouts for float16, bfloat16, float32, and float64.
• Free online tools for PDF, images, text, and random tasks.
  Open browser-based tools for PDF work, image cleanup, worksheets, text formatting, and random picks.
• Free QR code generator & scanner – create, verify.
  Generate QR codes for URLs, text, Wi-Fi, contacts, phone, email, and SMS.
• Fullscreen Clock.
  Show a large fullscreen clock in your browser with analog and digital views, seconds toggle, timezone options.

G

• Genko yoshi manuscript paper PDF generator.
  Generate genko yoshi manuscript paper with configurable page size, margins, character grid settings.
• Gradient Generator.
  Build quick linear or radial CSS gradients from 2 or 3 colors, preview the result, and copy the CSS string in your.
• Graph paper PDF generator.
  Generate print-ready SVG graph paper in millimeters: Cartesian, polar, log-log, semilog, and isometric grids.

H

• Habit Tracker Paper (Printable PDF)｜CalcBE.
  Generate monthly or yearly habit tracker paper as precise millimeter SVG with weekday labels, weekly separators.
• Hash Generator Tool.
  Generate SHA-1, SHA-256, and SHA-512 hashes for text or files in your browser.
• Hex grid paper PDF generator (chemistry, crystals, maps).
  Generate hex grid paper in millimeters with flat-top or pointy-top orientation, custom spacing, margins, and clean SVG.

I

• Image Resizer & Format Converter.
  Resize and convert images in your browser. Set width, height, format, and quality, then download—no uploads.
• Images to PDF – combine photos in browser.
  Convert multiple images to a single PDF with page size, orientation, margins, and fit options.
• Interval Timer (HIIT & Tabata).
  Analog + digital interval timer for HIIT/Tabata.
• IPv4 subnet & CIDR calculator – network address, host.
  Convert any IPv4 address and prefix length into its network address, broadcast address, usable host range.

J

• JSON Diff Tool.
  Compare two JSON documents online by structure.
• JSON Formatter & Validator.
  Pretty-print, minify, and validate JSON in your browser.

L

• Lined paper PDF generator – ruled paper in mm.
  Generate lined (ruled) paper as an SVG in millimeters.
• List Shuffler (Random Order Generator) – fair shuffle.
  Shuffle a list fairly with Fisher–Yates.

M

• Merge PDFs – reorder and combine multiple files locally.
  Merge PDFs in your browser, reorder files, choose page ranges, and download with no upload.
• Military Time Converter: 24 Hour to 12 Hour, AM/PM.
  Convert military time to AM/PM and AM/PM to 24-hour time instantly.
• Multi Timer Calculator.
  Manage multiple countdown timers at once with analog + digital views, fullscreen focus, sound/notifications, presets.

N

• Number line & interval visualizer (inequality shading).
  Shade inequalities and interval unions on an interactive SVG number line.

O

• OKLCH Converter.
  Convert one color between HEX, RGB, HSL, OKLCH, and OKLab, then copy perceptual color values for modern design-token.
• Online Alarm Clock.
  Set alarms in your browser without installing apps. Supports repeats, snooze, sound, notifications, and fullscreen.
• Online Stopwatch with Analog + Digital Display.
  Run a high-precision stopwatch with analog and digital displays, lap tracking, fullscreen, keyboard shortcuts.
• Online Timer (Countdown).
  Set an online countdown timer with analog and digital displays, presets, quick adjustments, fullscreen, keyboard.

P

• Page numbers & watermarks – stamp PDFs in browser.
  Add page numbers or text watermarks to a PDF entirely in your browser.
• Paper templates hub (lined, grid, Cornell, to-do).
  Find lined paper, dot grid, Cornell notes, to-do sheets, habit trackers, graph paper, and more.
• Passphrase generator (Diceware-style) – random words.
  Generate a strong passphrase from random words (Diceware-style) locally in your browser.
• Password generator – strong secure random passwords.
  Generate strong random passwords in your browser with crypto.getRandomValues.
• Pattern String Generator — business IDs & sequences.
  Generate business-style IDs from a pattern (date, sequence, random).
• PDF compressor – shrink large PDF files in your browser.
  Reduce PDF size entirely in your browser.
• PDF form filler & flattener – complete forms and lock.
  Fill PDF form fields, preview highlights, keep fields editable or flatten them, and download instantly.
• PDF highlighter & annotator – markup in browser.
  Highlight, draw, and place text notes on PDFs in your browser.
• PDF metadata editor – edit title, author & keywords.
  Read and update PDF metadata such as title, author, subject, keywords, and dates entirely in your browser.
• PDF page organizer – reorder, rotate & delete pages.
  Reorder, rotate, duplicate, or delete PDF pages in your browser.
• PDF sign & stamp tool – add signatures and approval.
  Create a signature, place it on pages, add dates or approval stamps, and export a signed PDF.
• PDF to EMF converter – preserve vectors & text.
  Convert PDF to EMF in your browser while preserving vectors and text positions.
• PDF to images converter – export PDF pages as PNG.
  Convert PDF pages to PNG or JPEG entirely in your browser.
• PDF to SVG converter – preserve vectors & text.
  Convert PDF pages to SVG in your browser while preserving vectors and text positions.
• PDF to text converter – extract text in browser.
  Extract text from PDFs entirely in your browser.
• PDF Tools (browser-only).
  A fast, private PDF toolkit that runs entirely in your browser: compress, merge, split, convert images, extract text.
• Permutation test – exact p-value for A/B and paired.
  Run a permutation (randomization) test for two independent groups or paired samples.
• Pomodoro Timer with Analog & Digital Display.
  Run a pomodoro timer with analog and digital displays, automatic phase transitions, local stats, fullscreen, keyboard.
• Primary handwriting paper PDF generator (3-line).
  Generate primary handwriting paper with headline + dashed midline + baseline.

Q

• Query String Parser.
  Parse raw query strings or full URLs, inspect repeated keys, decode values, and copy a normalized query locally.
• Quick charts from pasted data — scatter / box plot.
  Paste spreadsheet data to generate scatter and box plots instantly.

R

• Random CSV generator – test data & schema JSON.
  Generate random CSV test data in your browser.
• Random Date Generator, Time Generator & Datetime Generator.
  Generate random dates, random times, or random datetimes with ranges, weekday filters, exclusions, time windows.
• Random distributions: samplers, tests & visualizers.
  Generate random samples from distributions, visualize histograms, and sanity-check randomness in your browser.
• Random JSON Generator (Test Data) — array & NDJSON.
  Generate JSON test data from a schema. Export as JSON array or NDJSON.
• Random Log Generator — Nginx, Apache & JSON logs.
  Generate fake access logs (Nginx/Apache) or JSONL logs with controllable distributions.
• Random number generator (integers, decimals, seed).
  Generate random numbers in your browser: integers or decimals, optional seed, unique mode, and one-click copy.
• Random Picker.
  Pick one or more random items from a list in your browser. Great for lotteries, giveaways, and classroom activities.
• Random SQL INSERT Generator — Postgres, MySQL, SQLite.
  Generate SQL INSERT statements from a schema for Postgres, MySQL, or SQLite.
• Random test data generators (CSV, IDs, time).
  Create CSV test data, random IDs, and timestamps locally in your browser.
• Random tools – generators, pickers, shuffles.
  Random generators and pickers that run entirely in your browser: numbers, dates, CSV test data, tokens, UUIDs.
• Random Walk & Markov Chain Visualizer.
  Run random walk (1D/2D/3D) and Markov chain simulations in your browser.
• Randomness beacon verifier – paste a beacon to verify.
  Paste a public beacon value to verify a deterministic draw or shuffle.
• Randomness Tests (chi-square, runs, ACF, JB).
  Run chi-square, runs, autocorrelation, and Jarque-Bera tests on bit or number sequences.
• Regex Tester Tool.
  Test JavaScript regular expressions online with pattern, flags, match preview, capture groups, and replace output.

S

• Seating Chart Generator (Random) — Classroom & Tables.
  Free online seating chart generator for classrooms and events.
• Secret Santa generator (exclusions) – draw names fairly.
  Generate Secret Santa assignments in your browser.
• Semantic Color Tokens.
  Turn an approved base color into semantic token names for product UI, docs, or marketing.
• Seyes (French ruled) paper PDF generator.
  Generate Seyes/French ruled paper in millimeters.
• Shuffle bias comparison – naive vs Fisher–Yates.
  Compare shuffle bias: naive swap-everywhere vs Fisher–Yates (and optional sort(() => random - 0.5)).
• Split PDF files – extract page ranges or every N pages.
  Split a PDF into multiple files directly in your browser.
• Staff paper PDF generator.
  Generate staff paper in millimeters. Adjust staff spacing, system count (auto/manual), bar guides, lyric lines.
• State Color Tokens.
  Turn approved component token aliases into hover, active, disabled, focus, or selected state tokens.
• Step-by-step solution PDF exporter — multi-language.
  Build printable, step-by-step solution sheets with numbering styles, language options, and attachments.
• Study timetable (time blocking) PDF generator.
  Create daily or weekly time-blocking timetables in millimeters with adjustable columns, labels, and margins.
• Synthetic Time Series Generator — trend, seasonality.
  Generate synthetic time series data with trend, seasonality, noise, missing values, and outliers.

T

• TAB sheet PDF generator.
  Generate guitar/bass TAB sheets in millimeters.
• Team generator – random teams & groups.
  Split a list of names into random teams or groups in your browser.
• Text Case Converter — upper/lower/title.
  Convert text between upper, lower, title, sentence, snake_case, camelCase, and kebab-case instantly in your browser.
• Text Diff Tool.
  Compare two plain text blocks online line by line.
• Theme Color Tokens.
  Turn one approved base color into light, dark, brand-alt, and high-contrast token bundles.
• Todo checklist paper PDF generator (printable).
  Generate printable todo/checklist paper with checkboxes.
• Token Alias Planner.
  Plan token alias depth and fallback chains across semantic, component, state, and theme layers before naming.
• Token Category Mapper.
  Decide whether a token belongs in semantic, component, state, or theme layers before naming, audit, or export.
• Token Conflict Checker.
  Check where one token role creates direct conflicts, shadowed overrides, and redundant layers across theme, state.
• Token Counter.
  Count characters, words, lines, bytes, and rough token estimates for mixed English and CJK text.
• Token Dependency Graph.
  Map upstream aliases and downstream token dependents so you can see what breaks before renaming, replacing.
• Token Deprecation Plan.
  Turn token change scope into a deprecation plan with alias grace, warning channel, freeze timing, and hard-removal.
• Token Fallback Map.
  Map fallback order, override winner, and last-resort source when semantic, component, state, and theme tokens can all.
• Token generator – secure random strings (base64url, hex).
  Generate secure random tokens and random strings locally in your browser.
• Token Impact Simulator.
  Simulate which branches, tokens, and component surfaces change first when you rename, replace, or remove one token.
• Token Migration Status.
  Track token adoption, replacement coverage, blockers, and remaining consumers before freeze, deprecation, and removal.
• Token Override Matrix.
  Compare how one token role changes winners across theme, state, and platform scenarios after fallback order already.
• Token Resolution Debugger.
  Trace one token from public request through alias hops, layer candidates, and last-resort fallback so you can explain.
• Token Rollout Checklist.
  Turn token impact estimates into a release checklist for visual diff, coverage, docs, and blocker review before merge.
• Triangular Distribution Generator (min/mode/max).
  Generate samples from a triangular distribution using min/mode/max and visualize the PDF and histogram.
• TRPG dice check (d20/d100, pools) with PNG sharing.
  Run d20/d100 checks with advantage/disadvantage, compare vs DC, and roll dice pools to count successes.
• Truncated Normal Generator & Visualizer.
  Generate samples from a truncated normal distribution with lower/upper bounds and visualize the PDF/CDF and histogram.

U

• Unix Timestamp Converter & Epoch to Date Converter.
  Convert Unix epoch seconds or milliseconds to human-readable date/time and back.
• URL Encoder / Decoder Tool.
  Percent-encode text, decode strings, and parse full URLs with an editable query parameter list in your browser.
• UUID Generator (v4/v7) – bulk, format, validate.
  Generate UUID v4 or UUID v7 in bulk, format them (canonical/URN/braces), copy or download, and validate UUIDs with v7.

V

• Verifiable random draw (commit-reveal) – auditable.
  Run a verifiable random draw with commit-reveal logs so participants can verify every draw.

W

• Weibull Distribution Generator & Visualizer.
  Generate random samples from a Weibull distribution and visualize the PDF and histogram.
• Weighted Random Picker & Randomizer.
  Use this weighted random picker and randomizer to draw winners by weight, ratio, or raffle entries.
• World Clock Board (Multiple Time Zones).
  Compare multiple city times with analog + digital clocks, work-hour highlights, shareable URLs, and JSON.

Z

• Zenkaku/Hankaku Converter – kana, fullwidth/halfwidth.
  Convert Japanese text between fullwidth/halfwidth and Hiragana/Katakana in your browser.