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Every page on this site, in one place: 97 tools grouped by category, the category hubs that introduce them, the written guides, and the information and legal pages. This index is generated from the same data that builds the site, so it cannot fall out of step with it.

Site pages

Legal and data handling

Category hubs

PDF Tools (12) — Merge, split, rotate, crop, sign, watermark, number, compress and convert PDF files in your browser.
Organise PDF Pages (3) — Combine several PDFs into one, split a document into separate files, and rotate pages.
Edit PDF Content (5) — Annotate, sign, watermark, number and crop PDF pages without uploading the document.
Optimise PDF Size (1) — Reduce PDF file size in the browser, with an honest report of what was actually saved.
Convert To and From PDF (3) — Turn images into a PDF, export PDF pages as JPG images, and extract text from scans with OCR.
Image Tools (8) — Compress, crop, convert, blur faces in, and extract colours from images in your browser.
Video and Audio Tools (4) — Record your screen, trim video, convert audio, and turn a clip into an animated GIF.
Developer Tools (15) — Format and validate JSON, test regular expressions, decode tokens, convert data formats and inspect schedules.
Security Tools (6) — Generate passwords and UUIDs, compute hashes and HMACs, inspect JWTs, and encrypt text.
Web Tools (4) — Encode URLs and HTML entities, generate QR codes, and inspect what your browser reports about your device.
Text Tools (3) — Generate placeholder text, convert between naming cases, and count words, characters and reading time.
Unit Converters (13) — Convert length, weight, temperature, volume, area, speed, time, power, energy, pressure, data and storage units.
Financial Calculators (8) — Estimate mortgage, loan, car, credit-card, investment and retirement figures with standard formulas.
Health and Fitness Calculators (8) — Calculate BMI, BMR, calorie needs, macros, body fat, ideal weight and pregnancy dates from published formulas.
Maths Calculators (8) — Evaluate expressions, work with fractions, percentages, triangles, volumes, statistics and sequences.
Everyday Calculators (8) — Work out ages, date differences, worked hours, grades, GPA, height conversions and concrete volumes.

All tools

Developer (15)

JSON CompareCompare two JSON objects and highlight differences.
JSON PrettierFormat and validate raw JSON data.
Text ComparisonCompare two texts and highlight differences.
RegEx TesterTest and visualize regular expressions.
Code MinifierMinify JS, CSS, HTML and SQL code.
Base64 ConverterEncode and decode text or images.
JSON to InterfaceConvert JSON objects to TypeScript interfaces.
Code FormatterBeautify SQL, HTML, CSS code.
YAML ↔ JSONConvert between YAML and JSON.
Markdown EditorWrite markdown with live preview.
Cron ParserExplain cron expressions in English.
Curl to FetchConvert Curl commands to JS Fetch.
Epoch ConverterConvert Unix timestamps to dates.
Unit ConverterConvert across twelve measurement categories in one place.
Chmod CalculatorVisual Unix permission generator.

Finance (8)

Mortgage CalculatorEstimate monthly payments including property tax, insurance and HOA fees.
Loan CalculatorEstimate monthly payments for personal or business loans.
Auto Loan CalculatorCalculate car payments including trade-in value.
Interest CalculatorProject compound growth with optional monthly contributions.
Payment CalculatorDetermine credit card payoff time and total interest.
Retirement CalculatorPlan your retirement savings and goals.
Amortization CalculatorCalculate the monthly payment and total interest on an amortising loan.
Investment CalculatorCalculate potential investment returns.

Converter (13)

Time Zone ConverterConvert a time between zones and see current world times.
Length ConverterConvert meters, feet, miles, etc.
Weight & MassConvert kg, pounds, ounces, etc.
TemperatureCelsius, Fahrenheit, Kelvin.
Volume ConverterLiters, gallons, cups, etc.
Area ConverterSquare meters, acres, hectares.
Digital StorageBits and bytes in binary and decimal multiples.
Speed ConverterMPH, KM/H, knots, Mach.
Time ConverterSeconds, minutes, hours, days.
Power ConverterWatts, kilowatts, horsepower.
Energy ConverterJoules, calories, KWH, BTUs.
Pressure ConverterPascals, bar, PSI, atmospheres.
Data TransferMbps vs MB/s (Internet Speed).

Health & Fitness (8)

BMI CalculatorCalculate your Body Mass Index (BMI).
Calorie CalculatorTurn a basal metabolic rate into a daily calorie target.
Body Fat CalculatorEstimate body fat percentage.
BMR CalculatorCalculate Basal Metabolic Rate.
Macro CalculatorDetermine optimal macronutrient ratios.
Ideal WeightFind your ideal weight range.
Pregnancy CalculatorTrack pregnancy progress.
Pregnancy Weight GainEstimate healthy weight gain.

Math (8)

Scientific CalculatorEvaluate typed expressions with functions, constants and precedence.
Fraction CalculatorAdd, subtract, multiply, and divide fractions.
Percentage CalculatorCalculate percentage changes and values.
Triangle CalculatorCalculate area, perimeter, angles and heights from three sides.
Volume CalculatorCalculate volume of various 3D shapes.
Standard Deviation CalculatorCalculate variance and standard deviation.
Random Number GeneratorPick a random number between a range.
Number Sequence CalculatorFind the nth term of an arithmetic or geometric sequence.

Image (8)

Compress ImageReduce image file size with an adjustable quality setting.
Crop ImageCrop and rotate images before converting.
Image ConverterConvert between PNG, JPG, and WebP.
Privacy BlurAutomatically detect and blur faces.
Color PickerExtract palettes from images.
SVG OptimizerMinify and clean SVG code.
Meme GeneratorAdd text to images easily.
Favicon GeneratorCreate icons from images.

Media (4)

Screen RecorderRecord your screen and download.
Video TrimmerTrim video clips precisely.
Audio ConverterConvert audio formats or extract from video.
GIF MakerCreate animated GIFs from videos.

Security (6)

Password GeneratorCreate strong, random passwords.
Hash GeneratorGenerate MD5, SHA-1, SHA-256 hashes.
Encryption ToolEncrypt text with AES-256-GCM and a passphrase.
JWT DebuggerDecode and inspect JWT tokens.
HMAC GeneratorCreate keyed-hash message codes.
UUID GeneratorGenerate random UUIDs (v4).

Web (4)

URL EncoderEncode/Decode URL strings.
HTML Entity EncoderConvert characters to HTML entities.
QR Code GeneratorCreate QR codes from text/URL.
Device InfoView IP, UA, and Screen info.

Text (3)

Lorem IpsumGenerate placeholder text by words, sentences or paragraphs.
Case ConverterCamel, Snake, Pascal, Kebab case.
Word CounterCount words, chars, lines.

Organize (3)

Merge PDFCombine several PDF files into one, in the order you choose.
Split PDFSelect the pages you want and save them as a new document.
Rotate PDFRotate pages in 90-degree steps and save the new orientation.

Create & Convert (3)

Image to PDFTransform your images into portable PDF documents.
PDF to JPGConvert PDF pages to high-quality JPG images.
OCR PDFExtract text from scanned PDF documents.

Optimize (1)

Compress PDFReduce PDF file size, with the real saving reported honestly.

Edit (5)

PDF EditorAdd text, images, shapes or freehand annotations to a PDF document.
WatermarkAdd stamp, text or logo to your PDF.
Page NumbersAdd page numbers to your document.
Sign PDFDraw and add your signature to PDFs.
Crop PDFTrim the margins of a page by adjusting its visible area.

Others (8)

Age CalculatorCalculate your exact age in years, months, and days.
Date CalculatorAdd or subtract days, or count the days between two dates.
Time CalculatorAdd or subtract time values.
Hours CalculatorCalculate hours worked or time differences.
GPA CalculatorCalculate your semester and cumulative GPA.
Grade CalculatorDetermine the grade needed on an exam.
Height CalculatorConvert height between centimetres and feet and inches.
Concrete CalculatorEstimate concrete volume for a slab, in cubic yards and bags.

Guides

What “processed in your browser” really means — Which parts of a browser-based tool touch the network, which do not, and how to check for yourself in DevTools.
Fixing invalid JSON: the eight errors that cause most failures — Trailing commas, single quotes, unescaped characters, NaN, duplicate keys and large integers — with the exact parser message each one produces.
Password strength, measured properly — Why length beats complexity rules, how entropy is calculated, and what a generated password protects you from.
Hashing, HMAC and encryption are three different things — What each one is for, which of them you can reverse, and why MD5 still has a legitimate use.
Why PDF compression sometimes does nothing — What actually occupies space in a PDF, which files can shrink, and the trade-off you accept when pages are rasterised.
Choosing between PNG, JPEG and WebP — Transparency, artefacts, and why converting a PNG screenshot to JPEG usually looks worse at the same file size.
Writing regular expressions that do not hang — Greedy versus lazy quantifiers, the flags that matter, and the nested-repetition pattern that freezes a browser tab.
Reading and writing cron expressions — Field order, the difference between */5 and 5, the day-of-month and day-of-week trap, and how to sanity-check a schedule.
Where unit conversions lose precision — Binary versus decimal storage units, floating-point rounding, and how many digits you are entitled to keep.
How BMI, BMR and body-fat formulas are calculated — The equations behind the fitness calculators, the populations they were derived from, and where they are known to be wrong.