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Free online tools that run in your browser
Your browser is the backend. Most tools process your input entirely on your device. Pratron doesn’t receive the contents of your work.
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89 of 89 tools match.
Converters
Length ConverterConvert between meters, kilometers, miles, feet, inches, yards, and more — instantly and accurately.Weight ConverterConvert kilograms, grams, pounds, ounces, stones, and metric tons with exact conversion factors.Temperature ConverterConvert between Celsius, Fahrenheit, and Kelvin instantly with the standard formulas.Data Size ConverterConvert bits, bytes, KB, MB, GB, TB — including binary units KiB, MiB, GiB — with both 1000 and 1024 factors.Speed ConverterConvert km/h, mph, m/s, knots, and ft/s instantly — handy for driving, aviation, and sports.Area ConverterConvert square meters, square feet, acres, hectares, and more for real estate, land, and construction.Volume ConverterConvert liters, gallons, cups, milliliters, fluid ounces, and more — perfect for cooking and chemistry.Time Unit ConverterConvert milliseconds, seconds, minutes, hours, days, weeks, months, and years.Number Base ConverterConvert numbers between binary, octal, decimal, and hexadecimal — supports arbitrarily large integers.Roman Numeral ConverterConvert numbers to Roman numerals and back — supports values from 1 to 3999 with instant validation.Number to Words ConverterSpell out any number in English words — plain text, US dollar amounts, or check-writing format.ISBN Validator & ConverterValidate any ISBN's check digit and convert between ISBN-10 and ISBN-13 formats instantly.VIN DecoderDecode a 17-character VIN: validate the check digit, find the model year, country, and manufacturer — free.Unix Timestamp ConverterConvert Unix timestamps to human-readable dates and back. Supports seconds and milliseconds, UTC and local time.Pressure ConverterConvert psi, bar, kPa, atmospheres, and mmHg — for tyres, gauges, weather, and blood pressure readings.Power ConverterConvert kilowatts, horsepower, metric PS, and BTU per hour — for engines, motors, and air conditioners.Energy ConverterConvert joules, kilowatt-hours, calories, kilocalories, and BTU — for electricity bills, food, and physics.Angle ConverterConvert degrees, radians, gradians, arcminutes, arcseconds, and turns — for maths, CSS, and surveying.Frequency ConverterConvert Hz, kHz, MHz, GHz, rpm, BPM, and rad/s — for audio, radio, engines, and screen refresh rates.Fuel Economy ConverterConvert MPG to L/100km and back, including imperial MPG and km per liter — with the inverse maths handled.Data Transfer Rate ConverterConvert Mbps to MB/s and back — the eight-to-one gap between the speed you buy and the speed you see.
Calculators
Percentage CalculatorCalculate percentages three ways: X% of Y, what percent X is of Y, and percentage increase or decrease.BMI CalculatorCalculate your Body Mass Index in metric or imperial units and see the WHO weight category it falls into.Loan CalculatorCalculate your monthly loan payment, total interest, and total cost from the amount, rate, and term.Compound Interest CalculatorSee how savings grow with compound interest: initial deposit, monthly contributions, rate, and time.Tip CalculatorCalculate the tip and split the bill between any number of people — with quick percentage presets.Discount CalculatorCalculate the sale price after a percentage discount and see exactly how much you save.Age CalculatorCalculate exact age in years, months, and days from a date of birth — plus a countdown to the next birthday.Date Difference CalculatorCount the days, weeks, months, and years between two dates — including or excluding the end date.Mortgage CalculatorEstimate the total monthly housing cost: principal and interest, property tax, insurance, PMI, and HOA dues.Hours CalculatorAdd up worked hours from start and end times, subtract unpaid breaks, and get decimal hours and gross pay.VAT & Sales Tax CalculatorAdd tax to a net price or take it back out of a gross one, at any rate you enter — no built-in rate tables.Hourly to Salary ConverterConvert pay between hourly, daily, weekly, biweekly, monthly, and annual — with your own schedule.Unit Price CalculatorCompare packages of different sizes by price per kilogram, liter, or item, and see which is really cheaper.
Generators
QR Code GeneratorCreate free QR codes for URLs, text, Wi-Fi, and more. Customize size and colors, then download as PNG.Password GeneratorGenerate strong, random passwords with custom length and character sets — created locally, never transmitted.UUID GeneratorGenerate random UUIDs (v4) and time-ordered UUIDs (v7) in bulk. Copy one or all with a click.Hash GeneratorCompute MD5, SHA-1, SHA-256, and SHA-512 hashes of any text instantly in your browser.Lorem Ipsum GeneratorGenerate lorem ipsum placeholder text by paragraphs, sentences, or words for your designs and mockups.Random Number GeneratorGenerate random numbers in any range — single picks, multiple values, unique draws, dice, and lottery style.Barcode GeneratorCreate CODE128, EAN-13, UPC, and other barcodes online and download them as PNG or SVG.Slug GeneratorConvert any title or phrase into a clean, SEO-friendly URL slug — lowercase, hyphenated, accent-free.htpasswd GeneratorGenerate a bcrypt .htpasswd line for HTTP basic auth, hashed entirely in your browser and never uploaded.
Text Tools
Word CounterCount words, characters, sentences, and paragraphs in real time — with reading and speaking time estimates.Case ConverterConvert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, and more.Remove Duplicate LinesDelete duplicate lines from any list or text — with options to trim whitespace and ignore case.Sort LinesSort lines of text alphabetically, numerically, naturally, in reverse — or shuffle them randomly.Text Diff CheckerCompare two texts side by side and see added, removed, and unchanged lines highlighted instantly.Markdown PreviewWrite Markdown and see the rendered result live — headings, lists, tables, code blocks, and links.HTML to Markdown ConverterTurn HTML into clean Markdown, with control over heading style, bullet markers, and code blocks.Find and Replace TextReplace text across a whole document at once, literally or by regular expression with capture groups.
Developer Tools
Base64 Encoder / DecoderEncode text to Base64 or decode Base64 back to text — full Unicode support, plus URL-safe variant.URL Encoder / DecoderPercent-encode text for safe use in URLs, or decode %20 and friends back to readable text.HTML Entity Encoder / DecoderEscape special characters to HTML entities (&, <, ") or decode entities back to plain text.JSON Formatter & ValidatorFormat, validate, and minify JSON with syntax-error messages, custom indentation, and key sorting.JSON ⇄ YAML ConverterConvert JSON to YAML and YAML to JSON instantly — ideal for Kubernetes, CI configs, and OpenAPI specs.CSV ⇄ JSON ConverterConvert CSV data to a JSON array of objects and back — with delimiter auto-detection and header support.SQL FormatterBeautify SQL queries with proper indentation and keyword casing — supports PostgreSQL, MySQL, T-SQL, and more.JWT DecoderDecode a JSON Web Token to inspect its header and payload — with human-readable expiry timestamps.Regex TesterTest regular expressions against sample text with live match highlighting and capture-group details.Cron Expression ParserTranslate cron expressions into plain English and understand each of the five fields at a glance.Chmod CalculatorConvert Unix file permissions between checkbox, octal (755), and symbolic (rwxr-xr-x) notation.IP Subnet CalculatorCalculate network address, broadcast, host range, and usable host count from an IPv4 address and CIDR prefix.HTML FormatterIndent and re-align minified or messy HTML, with control over indentation and line wrapping.CSS FormatterExpand minified CSS into readable rules, one declaration per line, with consistent indentation.JavaScript FormatterRe-indent minified or inconsistent JavaScript, JSON, and TypeScript-flavoured code without rewriting it.XML Formatter & ValidatorIndent XML and check that it is well-formed, with the parser's own error message when it is not.URL Parser & Query BuilderBreak a URL into its parts, read query parameters decoded, and edit them to rebuild a correct URL.
Design Tools
Color ConverterConvert colors between HEX, RGB, and HSL with a live preview and WCAG contrast check against black and white.CSS Gradient GeneratorDesign linear and radial CSS gradients visually and copy the generated CSS with one click.Box Shadow GeneratorCraft CSS box shadows visually — offset, blur, spread, color, opacity, inset — and copy the code.Color Contrast CheckerCheck any two colors against WCAG AA and AAA for body text, large text, and non-text elements.Cubic Bezier EditorBuild a CSS easing curve by dragging its control points, with presets and a live motion preview.Border Radius GeneratorRound corners individually or together, in px, rem, or percent, with a live preview and copyable CSS.Aspect Ratio CalculatorFind the missing width or height for any ratio, simplify a size to its ratio, and copy the CSS.Fluid Typography GeneratorGenerate a CSS clamp() that scales font size smoothly between two viewport widths — no media queries.
Image Tools
Image CompressorCompress and resize JPEG, PNG, and WebP images in your browser — no upload, no quality guesswork.EXIF RemoverSee the hidden metadata in your photos — camera, date, GPS location — and download a clean copy without it.Favicon GeneratorTurn any logo into a complete favicon set: favicon.ico, Apple touch icon, and PWA icons with ready HTML.Image ResizerResize an image to exact pixel dimensions or a percentage, with the aspect ratio locked if you want it.Image ConverterConvert between PNG, JPEG, and WebP in your browser, with control over quality and transparency.Image CropperCrop an image to any region or a fixed aspect ratio, by dragging or by typing exact pixel coordinates.Image to Base64Encode an image as a Base64 data URI, ready to paste into CSS, HTML, or Markdown.Image Color PickerPick a colour from anywhere in an image and get its HEX, RGB, and HSL values, plus the dominant palette.
PDF Tools
Merge PDFCombine several PDFs into one, in the order you choose, without uploading a single page.Split PDFExtract any pages or ranges from a PDF into a new document, in the order you specify.Rotate PDFTurn some or all pages of a PDF by 90, 180, or 270 degrees and save the corrected file.Images to PDFTurn JPEG or PNG images into a single PDF, one page each, at A4, Letter, or the image's own size.PDF to ImagesRender PDF pages as PNG or JPEG images at your chosen resolution, entirely in your browser.