Tiny tools that save you time.

Calculate percentages, increases, and decreases instantly.

Find exact age in years, months, and days from any birth date.

Convert between Unix time and human-readable dates.

Calculate Body Mass Index from height and weight, in metric or imperial.

Count words, characters, sentences, and reading time as you type.

Generate strong, random passwords with custom length and character rules.

Split a bill and calculate the right tip in seconds.

Convert length, weight, and temperature between common units.

Convert colors between HEX, RGB, and HSL with a live preview.

Convert text to UPPERCASE, lowercase, Title Case, camelCase, and more.

Calculate monthly loan payments and total interest.

See how savings or investments grow with compound interest over time.

Generate random numbers in a range, with or without duplicates.

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

Encode text to Base64 or decode Base64 back to plain text.

Find the number of days, weeks, or months between two dates.

Count down live to any future date and time.

Generate SHA-1, SHA-256, and SHA-512 hashes of any text.

Test a regular expression against text and see every match highlighted.

Generate random version 4 UUIDs, one or many at a time.

Convert between two currencies using an exchange rate you enter.

Turn any text or URL into a downloadable, scannable QR code.

Estimate your monthly mortgage payment, including tax, insurance, and PMI.

Decode 4, 5, and 6-band resistor color codes into resistance, tolerance, and temperature coefficient.

Calculate percentages, increases, and decreases instantly.

Split a bill and calculate the right tip in seconds.

Convert length, weight, and temperature between common units.

Generate random numbers in a range, with or without duplicates.

Convert between Roman numerals and regular numbers.

Convert instantly between fractions, decimals, and percentages.

Check whether a number is prime and see its factors.

A full scientific calculator with trig, logs, powers, and memory.

Convert between cups, tablespoons, teaspoons, milliliters, and more.

Find the mean, median, mode, and range of a list of numbers instantly.

Find the greatest common divisor and least common multiple of two or more numbers.

Solve ax² + bx + c = 0 for real or complex roots, with discriminant and vertex.

Find exact age in years, months, and days from any birth date.

Convert between Unix time and human-readable dates.

Find the number of days, weeks, or months between two dates.

Count down live to any future date and time.

Convert a date and time between time zones around the world.

Count business days between two dates, excluding weekends.

Find what day of the week any past or future date falls on.

A simple stopwatch with lap times, accurate to the millisecond.

Track the current time in any number of cities at once, updated live.

Add or subtract years, months, and days from any date.

Check whether any year is a leap year, and see exactly why.

Find the exact duration between two times of day, including overnight spans.

Calculate Body Mass Index from height and weight, in metric or imperial.

Estimate daily calorie needs based on age, sex, height, weight, and activity level.

Estimate a daily water intake target based on body weight and activity.

Estimate a due date and current week of pregnancy from the last menstrual period.

Find the best times to sleep or wake up based on 90-minute sleep cycles.

Estimate body fat percentage using the US Navy tape-measure method.

Estimate your dog's age in human years based on their size.

Estimate a healthy weight range from height using four published formulas.

Find your training heart rate zones based on age and resting heart rate.

Estimate ovulation day and fertile window from your last period.

Calculate waist-to-hip ratio and its associated health risk category.

Convert a step count into walking distance and estimated calories burned.

Count words, characters, sentences, and reading time as you type.

Convert text to UPPERCASE, lowercase, Title Case, camelCase, and more.

Generate placeholder text by paragraphs, sentences, or words.

Estimate how easy a piece of text is to read.

Reverse text by character, word order, or line order.

Translate text to Morse code, or Morse code back to text.

Check your text against X, Instagram, TikTok, and other platform limits.

Have any text read aloud using your browser's built-in voices.

See which words appear most often in a block of text.

Search hundreds of emoji by keyword and copy them with one click.

Check whether a word, phrase, or number reads the same forwards and backwards.

Remove duplicate lines from any list, keeping the first occurrence.

Generate strong, random passwords with custom length and character rules.

Generate SHA-1, SHA-256, and SHA-512 hashes of any text.

See how strong a password is and why, without it ever leaving your browser.

Encrypt or decrypt text with a passphrase, using AES-256-GCM.

Compute a file's SHA-1/256/512 checksum and check it against an expected value.

Generate the same rotating codes as an authenticator app, from a Base32 secret.

Generate a memorable, random word-based passphrase.

Check a card number against the Luhn checksum and detect its card type.

Generate an HMAC signature for a message using a secret key.

Encode text to Base32 or decode Base32 back to plain text.

Encrypt or decrypt any file with a passphrase, using AES-256-GCM.

Validate an IBAN's format and mod-97 checksum.

Convert colors between HEX, RGB, and HSL with a live preview.

Generate complementary, analogous, and shade palettes from one color.

Calculate a matching width or height for any aspect ratio.

Turn any text or URL into a downloadable, scannable QR code.

Design a box shadow visually and copy the ready-to-use CSS.

Turn an image into a full set of standard favicon sizes, ready to download.

Pull the dominant colors out of any image, with copyable hex codes.

Design rounded corners visually and copy the ready-to-use CSS.

Resize an image to exact dimensions or a percentage, right in your browser.

Generate a solid-color placeholder image at any size, ready to download.

Design a text shadow effect visually and copy the ready-to-use CSS.

See how a color appears under different types of color vision deficiency.

Turn any text into a scannable Code 39 barcode, ready to download.

Build a flexbox layout visually and copy the ready-to-use CSS.

Build a CSS grid layout visually and copy the ready-to-use CSS.

Design a frosted-glass card effect visually and copy the CSS.

Add top/bottom captions to an image and download it as a meme.

Convert an image between PNG, JPEG, and WebP in your browser.

Shrink an image's file size with a live quality/size preview.

Decode a QR code from an uploaded image or your camera.

Generate a QR code that lets phones join a WiFi network by scanning.

Generate a QR code that adds a contact card when scanned.

Calculate monthly loan payments and total interest.

See how savings or investments grow with compound interest over time.

Add or remove sales tax from a price in seconds.

Find the sale price and amount saved on a discounted item.

Convert between hourly wage and annual, monthly, or weekly salary.

Convert between two currencies using an exchange rate you enter.

Estimate your monthly mortgage payment, including tax, insurance, and PMI.

Project your retirement savings based on contributions and growth rate.

Calculate return on investment, in total and annualized terms.

See a full month-by-month breakdown of principal, interest, and balance.

See what a meeting actually costs based on attendees and their time.

Create a clean, printable invoice with line items and totals.

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

Encode text to Base64 or decode Base64 back to plain text.

Percent-encode or decode text and URLs safely.

Convert numbers between binary, octal, decimal, and hexadecimal.

Write Markdown and see the rendered HTML preview live.

Compare two blocks of text and highlight what changed.

Turn any title into a clean, URL-friendly slug.

Test a regular expression against text and see every match highlighted.

Generate random version 4 UUIDs, one or many at a time.

Escape text to safe HTML entities, or decode entities back to text.

Decode a JSON Web Token's header and payload without a server.

Turn a cron schedule expression into a plain-English description.

Build a linear gradient visually and copy the ready-to-use CSS.

Check whether a text and background color pair meets WCAG contrast rules.

Convert between px, em, rem, and pt for a given base font size.

Break a URL down into protocol, host, path, and query parameters.

Look up what any HTTP status code means.

Generate SEO and social-preview meta tags, with a live search-result preview.

Convert an image file into a Base64 data URI for embedding in code.

Shrink JavaScript for production using Terser, entirely in your browser.

Shrink CSS for production using CSSO, entirely in your browser.

See your screen resolution, viewport size, browser, and device details.

Calculate network address, broadcast, and usable host range from a CIDR block.

Build a properly quoted curl command from a method, URL, headers, and body.

Convert between YAML and JSON instantly, in either direction.

Convert between CSV and JSON, with correct handling of quoted fields.

Format and beautify SQL queries with consistent keywords and indentation.

Beautify HTML with clean indentation, or minify it to a single line.

Format, validate, and minify XML with clear error messages.

Generate a .gitignore file for your stack — Node, Python, Java, and more.

Generate a robots.txt crawler policy or a sitemap.xml from a list of URLs.

Generate realistic placeholder names, emails, addresses, and more for testing.

Turn CSV or spreadsheet data into a ready-to-paste Markdown table.

Beautify minified or messy JavaScript with clean, consistent indentation.

Clean up Python whitespace, tabs, and blank lines without touching logic.

Highlight Python code and copy it as colored HTML or plain text.

Generate a requirements.txt from Python import statements or a package list.

Convert Python dict/list literals to JSON, and back.

Convert text to a Python string literal (or back), in any quote style.

Build a pip install command with version pins, index URL, and common flags.

Generate the venv create/activate commands for your OS and shell.

Test Python re-style regex patterns, including named groups, against text.

Generate a Google, NumPy, or reST-style docstring from a function signature.

Add type hints to a Python function signature, inferred from default values.

Convert XML to JSON, and back, with attributes and arrays handled.

Compare two JSON objects and see exactly what changed.

Break a browser user agent string into browser, OS, and device info.

Paste CSV or spreadsheet data and get a ready-to-paste HTML table.

Calculate a weighted GPA from letter grades and credit hours.

Turn a test score into a percentage and letter grade.

Generate APA and MLA citations for websites, books, and journal articles.

Measure your typing speed in WPM and accuracy against a practice passage.

An interactive periodic table — search or click any element for details.

Build a deck of study flashcards that saves itself in your browser.

Generate a times table chart for any range of numbers.

Practice multiplication tables with a randomized quiz and instant scoring.

Calculate solution molarity, or the mass of solute needed for a target molarity.

Solve for speed, distance, or time using the classic physics formula.

Convert a calendar date to Roman numerals, or decode one back to a date.

An interactive unit circle showing sine, cosine, and tangent for any angle.

Flip a virtual coin, with a running tally of heads and tails.

Roll any combination of standard tabletop dice, from d4 to d20.

Split a list of names into random, evenly-sized teams or groups.

Generate a random, printable bingo card in seconds.

Pick one random winner from a list of names.

Ask a yes-or-no question and let fate decide.

Turn text into a banner, or an image into ASCII art.

Track scores for any number of players or teams with simple +/- counters.

Stay focused with 25-minute work sessions and timed breaks.

A simple to-do list that saves itself in your browser.

A quick scratchpad that auto-saves as you type — no account needed.

Track daily habits and streaks on a simple weekly grid.

A simple To Do / In Progress / Done board that saves itself in your browser.

Plan out your week day by day, saved automatically in your browser.

Decode 4, 5, and 6-band resistor color codes into resistance, tolerance, and temperature coefficient.

Solve for voltage, current, or resistance — plus power — from any two known values.

Find the current-limiting resistor needed to safely drive one or more LEDs.

Calculate output voltage from two resistors, or the R2 needed to hit a target voltage.

Estimate runtime for a battery-powered project from capacity and average current draw.

Convert between PWM frequency/duty cycle and raw on-time/off-time pulse widths.

Calculate resistor-capacitor time constant, cutoff frequency, and charge-time milestones.

Compute UART bit time, frame time, throughput, and baud rate divisor error.

Searchable pin reference for Arduino Uno/Nano/Mega, ESP32, ESP8266, and STM32 Blue Pill.

Set, clear, and toggle individual bits in an 8/16/32-bit register with live hex/binary output.

Decode 3-digit/letter capacitor markings like "104" or "4n7" into standard capacitance values.

Pick a safe wire gauge for a given current draw, run length, and acceptable voltage drop.

Tune Kp, Ki, and Kd and watch the closed-loop step response redraw live on an animated chart.

Decode the 4-band color code on an axial inductor into its inductance value.

Calculate resistor power dissipation and get a suggested safe wattage rating.

Combine any number of resistor values in series or parallel.

Combine any number of capacitor values in series or parallel.

Calculate astable frequency/duty cycle or monostable pulse width for a 555 timer.

Calculate inverting or non-inverting op-amp gain from feedback and input resistors.

Compute CRC-8, CRC-16, or CRC-32 checksums over text or hex bytes.

Size the series resistor for a zener shunt voltage regulator.

Convert between power/voltage ratios and decibels.

Find crystal load capacitance from C1/C2, or matched C1/C2 from a target CL.

Reformat a .ino sketch with clean, brace-based indentation.

Pinouts for Leonardo/Micro, Due, Pro Mini, ATtiny85, ESP32-C3/S3.

Compute map(value, fromLow, fromHigh, toLow, toHigh), truncation included.

Estimate Serial transfer time and effective throughput at a given baud rate.

See exactly when millis() or micros() overflow, and check interval math.

Convert analogRead() raw values to voltage, or the reverse, for 10/12-bit ADCs.

Convert servo angle (0-180°) to pulse width in microseconds, and back.

Generate Boards Manager URLs or arduino-cli commands for ESP32, RP2040, and more.

Highlight Arduino/C++ code and copy it as colored HTML or plain text.

Estimate global-variable SRAM usage against your board's memory budget.

Test your microphone online with a live input level meter.

Test your webcam online with a live preview, resolution, and snapshot.

Test every key on your keyboard with a live on-screen layout.

Test mouse buttons, scroll wheel, cursor tracking, and double-click speed.

Test left/right speaker channels and run a frequency sweep.

Cycle solid colors full-screen to spot dead or stuck pixels.

See your GPU vendor, renderer, WebGL version, and supported extensions.

Test multi-touch support and responsiveness with live touch points.

Test motion sensors with live tilt, acceleration, and rotation readouts.

Trigger preset or custom vibration patterns on your phone.

Test controller buttons and analog sticks with live visual feedback.