Free online tools
Find a tool for the task in front of you. Format data, create QR codes, convert files or calculate costs. Search below or browse a category. No account needed.
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Generators
Create QR codes, secure passwords, UUIDs, hashes, and more with our free generator tools.
Mailto Link Generator
Generate HTML mailto links with pre-filled subject, body, CC, and BCC fields
RSS Feed Generator
Create a valid RSS 2.0 XML feed from your blog posts or content items. Free, no signup required.
ICS File Generator
Create calendar event files for Google Calendar, Apple Calendar, and Outlook
Chord Progression Generator
Generate chord progressions in any key and scale mode
Online Metronome
Free online metronome with adjustable BPM, time signatures, and tempo markings for music practice
Online Tone Generator
Generate pure audio tones at any frequency (20 Hz–20 kHz) — sine, square, sawtooth and triangle waves. Free, runs in your browser.
iCal Event Generator
Create .ics calendar event files for Google Calendar, Apple Calendar, Outlook and more — free, no signup
Passphrase Generator
Generate strong, memorable passphrases using random words. Easy to remember and configurable to your security needs.
Mock Data Generator
Generate fake test data with realistic names, emails, phones, and more. Export as JSON, CSV, or SQL INSERT.
QR Code Generator
Create custom QR codes with colors and different sizes
Password Generator
Generate strong, secure passwords with custom options
UUID Generator
Generate unique identifiers (UUID v1 & v4)
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes
Lorem Ipsum Generator
Generate placeholder text for designs and mockups
Slug Generator
Convert text to URL-friendly slugs for SEO optimization
Cron Expression Generator
Build and validate cron expressions with a visual editor
Placeholder Image Generator
Generate placeholder images with custom dimensions and colors
Invoice Generator
Create professional invoices for your business or freelance work
Privacy Policy Generator
Generate a privacy policy for your website or app
Random Word Generator
Generate random English words by category — nouns, verbs, adjectives, adverbs
CPF Generator
Generate valid Brazilian CPF numbers for software testing, in bulk, by state.
CNPJ Generator
Generate valid Brazilian CNPJs for testing, including the new 2026 alphanumeric format.
Color Pallete Generator
Color Pallete Generator - Free online tool
Dice Roller
Roll 1 to 10 virtual dice: d4, d6, d8, d10, d12, d20 or d100, with totals.
Coin Flipper
Flip a virtual coin online — heads or tails — with real-time statistics and flip history.
Spin the Wheel
Random name picker wheel: add names, spin, and let the wheel choose.
Random Picker
Pick random names or items from a list online — one click, instant result
Pix QR Code Generator
Create a static Pix QR code and copy-paste code, with or without an amount
Random Team Generator
Paste names and split them into fair random teams or groups in one click.
Quote Generator
Printable quotes and estimates with line items, discounts, totals and saved drafts.
Receipt Generator
Printable payment receipts with the amount in words, ID checks and a Pix QR option.
Design Tools
Color palette generators, CSS gradient creators, and visual design utilities for web designers.
Hex Color Opacity Calculator
Convert a hex color code to hex8 (RRGGBBAA), rgba(), and hsla() with custom opacity
CSS Gradient Border Generator
Generate CSS gradient borders with live preview. Supports border-radius using the background-clip technique.
PPI Calculator
Calculate screen pixel density (PPI / pixels per inch) from display resolution and diagonal screen size
CSS Cubic Bezier Generator
Create custom CSS cubic-bezier() easing functions with a visual curve editor and animation preview
Z-Index Calculator
Visualize CSS z-index stacking order and resolve layering conflicts between elements
CSS Cubic Bezier Generator
Create custom cubic-bezier easing functions visually for CSS animations and transitions
Neumorphism Generator
Create soft UI (neumorphism) CSS effects with live preview
Color Palette Generator
Create, customize, and export beautiful color palettes for your design projects
CSS Gradient Generator
Create beautiful CSS gradients with live preview
Box Shadow Generator
Create CSS box shadows with visual editor
Color Converter
Convert colors between HEX, RGB, HSL, HSV, and CMYK formats
Color Contrast Checker
Check color contrast ratios for WCAG accessibility compliance
Pixel to REM Converter
Convert between px and rem units
Em to Px Converter
Convert em, rem, and px CSS units instantly
CSS Clamp Calculator
Generate CSS clamp() values for fluid, responsive typography and spacing
Developer Tools
JSON formatters, regex testers, diff checkers, and essential tools for software developers.
JSONL / NDJSON Formatter & Validator
Validate and format JSON Lines (JSONL / NDJSON) data online — line-by-line error reporting, compact and pretty-print modes
ESM ↔ CommonJS Converter
Convert between ES modules and CommonJS syntax online
Semver Bump Calculator
Calculate major, minor, and patch version bumps for semantic versioning
Iframe Generator
Generate iframe HTML embed code with full attribute control — width, height, sandbox, referrer policy and more
JavaScript Key Code Tester
Press any key to inspect its JavaScript keyboard event properties: key, code, keyCode, and modifiers
YAML Formatter
Format, validate and minify YAML online. Fix YAML syntax errors instantly in your browser — no signup required.
Indent Converter
Convert between tabs and spaces and normalize code indentation
KeyCode Finder
Press any key to instantly see its JavaScript event properties: event.key, event.code, keyCode, and Unicode code point
SemVer Calculator
Check if a version satisfies a semantic versioning range — decode ^, ~, and comparison operators online
SVG to React Component
Convert SVG markup into a ready-to-use React component. Transforms class→className, kebab-case props→camelCase, and inline styles automatically.
JWT Decoder
Decode JSON Web Tokens securely in your browser
JWT Encoder
Create and sign JSON Web Tokens with custom payloads
JSON Formatter
Format, validate, and beautify JSON data
Regex Tester
Test and debug regular expressions in real-time
Diff Checker
Compare two texts and highlight the differences
Markdown Preview
Write and preview Markdown in real-time
Meta Tag Generator
Generate complete meta tags for SEO and social previews.
Website Speed Test
Check loading speed and core performance metrics for any URL.
Keyword Density Checker
Check keyword density to optimize your content for search engines
SERP Snippet Preview
Preview Google result snippets and validate title/meta description length.
Robots.txt Generator
Generate robots.txt rules to control crawling and include sitemap directives.
Canonical URL Checker
Validate canonical URLs and catch common indexing mistakes.
Hreflang Generator
Create hreflang tags for multilingual SEO and validate locale mappings.
UTM Link Builder
Build UTM tracking parameters for campaigns
CPF Validator
Check one or hundreds of Brazilian CPF numbers at once, with the reason each one fails.
CNPJ Validator
Validate numeric and alphanumeric CNPJs in bulk and see which check digit failed.
HTTP Status Codes Reference
Complete HTTP status codes reference with descriptions — search 60+ codes from 1xx to 5xx. Free and instant.
CSS Specificity Calculator
Calculate CSS selector specificity
Subresource Integrity Generator
Subresource Integrity Generator - Free online tool
YAML Validator
Free online YAML validator. Paste your YAML and instantly check syntax, see error line numbers, and preview parsed structure as JSON. No signup needed.
JSON Validator
Validate and format JSON online — instant syntax checking
Chmod Converter
Chmod Converter - Free online tool
Mic Test
Check your microphone in the browser: live level meter, waveform and playback
What Is My Screen Resolution?
See your screen resolution, viewport size and pixel ratio, live
Webcam Test
Check your camera in the browser: live preview, real resolution, FPS and snapshot
Text & Writing
Word counters, case converters, and text manipulation tools for writers and content creators.
Palindrome Checker
Instantly check if text is a palindrome, with options to ignore case, spaces, and punctuation.
Syllable Counter
Count syllables in any word or text online. Line-by-line analysis, haiku checker, and per-word breakdown.
Leet Speak Generator (1337)
Convert text to leet speak (1337). Choose from 3 levels of l33tness for gaming profiles, memes, and online messages.
Anagram Solver
Find all words that can be formed from your letters — free word unscrambler online
Remove Line Breaks
Remove or replace line breaks from text instantly. Paste text from PDFs, emails or documents and clean it up.
Vigenère Cipher Encoder & Decoder
Encode and decode text with the Vigenère polyalphabetic cipher online. Enter a keyword to encrypt or decrypt any message instantly, with an interactive Vigenère square.
Word Counter
Count words, characters, sentences, and paragraphs in your text
Case Converter
Convert text between different case formats instantly
Character Counter
Count visible characters, Unicode code points, UTF-16 units and UTF-8 bytes.
Remove Duplicate Lines
Remove duplicate lines from text
Sort Lines
Sort text lines in ascending or descending order using your language’s collation.
Text to Speech
Read any text aloud with your browser's voices, free and with no signup
Morse Code Translator
Translate text to Morse code and back
Caesar Cipher Encoder & Decoder
Encode and decode text using the Caesar cipher shift. Supports ROT13 and all 26 shift values.
Bold Text Generator
Generate bold, italic, and 10 Unicode text styles for Instagram, Twitter & social media. Copy and paste instantly.
Fancy Text Generator
Turn text into 26 fancy Unicode fonts you can copy and paste anywhere.
Readability Score Checker
Check Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and ARI readability scores of any text — free, instant, no signup.
Word Frequency Counter
Analyze word frequency in any text — see which words appear most often with counts and percentages
NATO Phonetic Alphabet
Convert any text to NATO phonetic alphabet. Instantly spell out words as Alpha, Bravo, Charlie and more — with a clickable reference table.
List Format Converter
Convert a column of items to comma-separated list, SQL IN clause, JSON array, and more formats online
Converters & Encoders
Convert between formats: Base64, URL encoding, timestamps, units, and image formats.
Number Formatter
Format numbers with locale-aware separators, currency symbols, and compact notation
Markdown to JSON Converter
Convert Markdown tables, lists, and YAML front matter to JSON instantly in your browser. Free, no signup required.
ISBN Validator
Validate ISBN-10 and ISBN-13 barcodes, check the check digit, and convert between formats
Hex to Tailwind Color Finder
Find the nearest Tailwind CSS color for any hex color
Image Converter
Convert images between PNG, JPG, and WebP formats
Base64 Encoder/Decoder
Encode and decode text to Base64 format
URL Encoder/Decoder
Encode and decode URLs for safe transmission
HTML Encoder/Decoder
Encode and decode HTML entities for safe display
Timestamp Converter
Convert between Unix timestamps and human dates
Unit Converter
Convert between different units of measurement
URL Shortener
Turn long URLs into short, shareable links instantly
CSV/JSON Converter
Convert between CSV and JSON formats easily
QR Code Decoder
Scan and decode QR codes from images
JSON to TypeScript Converter
Convert JSON objects to TypeScript interface or type definitions
Markdown to HTML Converter
Convert Markdown text to HTML with live preview
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal
Text Extractor (OCR)
Extract text from images using AI-powered OCR
YAML to JSON Converter
Convert YAML to JSON online — validate YAML syntax and get formatted JSON output instantly.
Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers instantly
Scientific Notation Converter
Convert between decimal and scientific notation. Supports E notation and engineering notation.
JSON to CSV Converter
Convert JSON data to CSV format
XML to JSON Converter
Convert XML to JSON with attributes and repeated elements, directly in your browser.
JSON to YAML Converter
Convert JSON to YAML format online — paste JSON and get clean YAML output instantly.
Image to Base64 Converter
Convert images to Base64 encoded strings for HTML, CSS, and APIs
Base64 to Image Converter
Decode Base64 strings to images — preview, inspect metadata, and download
Image Compressor
Compress images without losing quality
Biorhythm Tracker
Track your medication cycle and energy levels
Epoch/Unix Timestamp Converter
Convert between epoch timestamps and dates
Cron To Human
Cron To Human - Free online tool
HTML Entity Converter
Encode and decode HTML entities instantly
Number to Words Converter
Convert any number to written English words instantly — supports decimals, negatives, and currency
Hex Text Converter
Convert text to hexadecimal and hex to text online. Supports Unicode characters, multiple separators, and uppercase or lowercase output. Free, instant, no signup.
Military Time Converter
Convert between 12-hour AM/PM and 24-hour military time format instantly — with quick reference chart
Binary to Text Converter
Convert binary code to readable text — or encode text into binary. Supports space-separated and continuous binary strings.
Amount in Words
Write money and numbers in words: checks, dollars, reais, cardinals and ordinals.
Calculators
BMI calculator, age calculator, percentage calculator, and budget planning tools.
Recipe Scaler
Scale recipe ingredient quantities up or down for any number of servings instantly in your browser
Standard Deviation Calculator
Calculate standard deviation, variance, mean, median, mode, quartiles, and more — with step-by-step breakdown
Speed Distance Time Calculator
Calculate speed, distance, or time — enter any two values to solve for the third
Flooring Calculator
Calculate how much flooring you need for any room, including waste factor and cost estimate
Heat Index Calculator
Calculate the apparent "feels like" temperature from air temperature and relative humidity using the NWS Rothfusz equation. Shows heat danger levels.
Free Fall Calculator
Calculate free fall time, distance, and velocity for any planet gravity
APR to APY Calculator
Convert between Annual Percentage Rate and Annual Percentage Yield with compounding frequency support
NPV Calculator
Calculate net present value (NPV) and IRR from cash flows and a discount rate
Rule of 72 Calculator
Estimate how long it takes to double an investment using the Rule of 72
Frequency to Wavelength Calculator
Convert frequency to wavelength and back — supports Hz to THz and nm to km with EM spectrum region
Sunrise & Sunset Calculator
Calculate sunrise, sunset, golden hour, and twilight times for any location and date
Sales Tax Calculator
Calculate sales tax amount and total price — or remove tax from a total to find the pre-tax price. Includes common US state and international tax rate presets.
Slope Calculator
Calculate slope, distance, midpoint and line equation between two coordinate points
Tap Tempo BPM Calculator
Tap to find the BPM of any song or rhythm — see tempo name and note durations
Moon Phase Calculator
Calculate the moon phase for any date — see illumination %, lunar cycle progress, and upcoming new and full moon dates
Heart Rate Calculator
Calculate your maximum heart rate and 5 training zones by age — with Karvonen method support
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law. Enter any two values to solve the circuit.
Video Bitrate Calculator
Calculate the optimal video bitrate for streaming and encoding
Dew Point Calculator
Calculate dew point, heat index, and humidity comfort level from temperature and relative humidity. Instant, free, no signup.
Wind Chill Calculator
Calculate wind chill temperature and frostbite risk using the NOAA formula
Pixel Density Calculator (PPI)
Calculate pixels per inch (PPI) for any screen resolution and size
One Rep Max Calculator
Calculate your one rep max (1RM) using 5 proven formulas — then get a full training table with weights for every intensity level
Golden Ratio Calculator
Calculate golden ratio segments, golden rectangles, and check how close any two values are to phi (1.618).
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law. Instant V=IR solver for electronics and electrical engineering.
Resistor Color Code Calculator
Decode 4-band and 5-band resistor color codes to find resistance value and tolerance — free online tool
Prime Factorization Calculator
Find prime factors of any number. Shows prime factorization, exponential notation, and all divisors instantly.
BPM Calculator
Find the BPM of any song by tapping to the beat
Simple Interest Calculator
Calculate simple interest (I = P×r×t), total amount, and monthly schedule — free browser tool
FIRE Calculator
Calculate your Financial Independence Retire Early number and years to freedom
Triangle Calculator
Solve any triangle — enter any 3 known values to calculate all sides, angles, area, and properties
Net Worth Calculator
Calculate your net worth by adding up all assets and subtracting total liabilities
Combination & Permutation Calculator — nCr and nPr
Calculate combinations nCr and permutations nPr instantly with step-by-step factorial breakdown. Free online calculator.
Break-Even Calculator
Calculate break-even point in units and revenue for any business
Haversine Calculator
Calculate the great-circle distance between two latitude/longitude points. Instant results in km and miles with bearing and midpoint. No signup.
Percentage Calculator
Calculate percentages, percentage change, tips, and more
Age Calculator
Calculate your exact age in years, months, days, and more
BMI Calculator
Calculate your Body Mass Index and check your weight category
50/30/20 Budget Calculator
Calculate your budget using the 50/30/20 rule for financial planning
Tip Calculator
Calculate tips and split bills between friends
Pomodoro Timer
Stay focused with the Pomodoro technique timer
Aspect Ratio Calculator
Calculate and convert aspect ratios for images and video
Loan Calculator
Calculate monthly payments and total interest
Annuity Calculator
Calculate present value and future value of annuity payments with amortization schedule
Compound Interest Calculator
Calculate compound interest growth over time
CAGR Calculator
Calculate compound annual growth rate from start and end values
Profit Margin Calculator
Calculate profit and profit margin from cost and selling price.
ROI Calculator
Calculate return on investment
Debt-to-Income Ratio Calculator
Calculate your debt-to-income (DTI) ratio to see if you qualify for a mortgage or loan
Markup Calculator
Calculate markup on cost from cost and selling price.
Online Stopwatch
Simple stopwatch with lap times
Retirement Calculator
Calculate how much you need to retire and project your savings growth
Calorie Calculator
Calculate your daily calorie needs (BMR & TDEE) based on age, height, weight, and activity level.
Sleep Cycle Calculator
Calculate ideal bedtime and wake-up times based on 90-minute sleep cycles
Water Intake Calculator
Calculate how much water you should drink per day based on weight, activity level, climate, pregnancy, and breastfeeding
Brazil FGTS Calculator
FGTS deposits with TR + 3% a year, balance over time and the 40% fine
Brazil Net Salary Calculator 2026
Net CLT salary with 2026 INSS, income tax and the R$ 5,000 exemption
Brazil Termination Pay Calculator (Rescisão) 2026
CLT severance: notice, 13th, vacation, FGTS 40% fine and 2026 taxes
13th Salary Calculator (Brazil)
Brazilian 13th salary with both installments, INSS and income tax for 2026
Brazil Vacation Pay Calculator (Férias) 2026
CLT vacation pay with the 1/3 bonus, sold days, INSS and 2026 income tax
Brazil Overtime Calculator (Horas Extras)
CLT overtime at 50% and 100%, night premium with the short night hour, and DSR
Network Subnet Calculator
Network Subnet Calculator - Free online tool
Bandwidth Calculator
Bandwidth Calculator - Free online tool
Uptime Calculator
Calculate allowed downtime for any uptime SLA percentage — 99.9%, 99.99%, 99.999% and more
Split Bill Calculator
Split Bill Calculator - Free online tool
Grade Calculator
Grade Calculator - Free online tool
Scientific Calculator
Scientific Calculator - Free online tool
Statistics Calculator
Calculate mean, median, mode, standard deviation, and more
Probability Calculator
Calculate probability of events, compound probability, combinations, and permutations
Binary Calculator
Free binary calculator — add, subtract, multiply, divide and apply bitwise operations (AND, OR, XOR, NOT) on binary numbers. Results shown in binary, decimal, hex, and octal.
Hex Calculator
Hexadecimal arithmetic and bitwise operations with base conversion
Fraction Calculator
Fraction Calculator - Free online tool
Truth Table Generator
Truth Table Generator - Free online tool
Fibonacci Calculator
Fibonacci Calculator - Free online tool
Gcd Lcm Calculator
Gcd Lcm Calculator - Free online tool
Quadratic Formula Calculator
Solve quadratic equations ax²+bx+c=0 with step-by-step solution, discriminant, and roots
Area Calculator
Calculate the area of circles, rectangles, triangles, trapezoids, ellipses, and more
Body Fat Calculator
Calculate your body fat percentage using the US Navy method
Macro Calculator
Calculate your daily protein, fat, and carbohydrate targets in grams from any calorie goal
Ovulation Calculator
Find your ovulation day, fertile window and next period over three cycles
Due Date Calculator
Find your due date from your last period, conception or IVF transfer
Typing Speed Test
Test your typing speed and accuracy online for free
A/B Test Calculator
Calculate statistical significance for your A/B tests instantly
Days Until Calculator
Live countdown in days, hours and minutes to any date, with business days
Work Days Calculator
Work Days Calculator - Free online tool
Mortgage Amortization Calculator
Generate a complete mortgage amortization schedule with monthly and yearly payment breakdown
Spending Projection
Track your spending and income with a visual dashboard to project your financial future
Life in Weeks
See your whole life as a grid of weeks — one square per week, filled up to today
Meeting Cost Calculator
Price any meeting by the people in the room — per meeting, per year, and in hours burned
Caffeine Half-Life Calculator
Plot how much caffeine is still in your system at bedtime, drink by drink
CPS Test
Click speed test: how many clicks per second can you do in 1 to 60 seconds?
Hours Calculator
Add up work hours on a time card, with breaks, night shifts, overtime and pay
Reaction Time Test
Test your reflexes: click when the box changes colour, 5 tries, average in ms
AI Tools
AI-powered tools for content creation, resume writing, and professional branding.
ATS Resume Bullet Generator
Generate ATS-optimized resume bullets with strong action verbs and quantified achievements
LinkedIn Headline Generator
Create compelling LinkedIn headlines that attract recruiters
Viral Hook Generator
Generate scroll-stopping hooks for TikTok, Reels, and Shorts
Social Media Bio Generator
Generate compelling social media bios for any platform
About these tools
Do I need an account?
No. Choose a tool, enter the required information and use the result without signing up.
Does my data leave the browser?
Many tools process data locally. AI features and external lookups may send the necessary input to a service. Check the tool instructions and privacy policy before using sensitive information.
Which tool should I choose?
Use converters to change formats, generators to create codes or text, and calculators to compare values. Search by a tool name or the task you want to complete.
Can you build a tool like this for my business?
Yes. I build custom calculators, generators and internal tools, and they can live on your own site. Email contact@arielton.com with what the tool needs to do.