100% in your browser
Online tools that never upload your data
Files, text and keys are processed on your own device. No server ever sees them.
- Processed locallyYour browser does the work
- Zero uploadsNo server receives your files
- Works offlineLoad once, then cut the network
- No sign-upNo account, no tracking cookies
Developer Tools
- JSON Formatter & ValidatorBeautify, minify and validate JSON with precise error positions.
- Base64 Encoder & DecoderEncode or decode Base64 text, files and data URLs, with UTF-8 support.
- Cron Expression GeneratorBuild, explain and preview cron schedules in plain English.
- Password GeneratorGenerate strong random passwords and passphrases with an entropy readout.
- Regex TesterTest regular expressions live with match highlighting and capture groups.
- Unix Timestamp ConverterConvert Unix epoch seconds or milliseconds to a human date, and back.
- Chmod CalculatorTick permission boxes to get the octal chmod value, or type a value to see what it grants.
- JSON to CSV ConverterConvert JSON arrays to CSV and CSV back to JSON, with nested key flattening.
- JWT DecoderDecode a JWT header and payload, and check its expiry — offline.
- Subnet CalculatorEnter an address and prefix to get the network, broadcast, usable range and host count.
- UUID GeneratorGenerate cryptographically random UUID v4, time-ordered v7 and Nano IDs.
- Hash GeneratorGenerate SHA-256, SHA-384, SHA-512, SHA-1 and MD5 hashes of text or files.
- Text to BinarySee any text as binary, hexadecimal, decimal, octal and UTF-8 bytes at once.
- URL Encoder & DecoderPercent-encode or decode URLs and query strings, with a parameter breakdown.
Text Tools
- Text Diff CheckerCompare two blocks of text and highlight every added and removed line.
- Word & Character CounterLive word, character, sentence and reading-time counts as you type.
- Case ConverterConvert text between upper, lower, title, sentence, camel, snake and kebab case.
- Markdown to HTML ConverterConvert Markdown to clean HTML with a live side-by-side preview.
- Lorem Ipsum GeneratorGenerate classic or modern placeholder text by paragraph, sentence or word.
Converters
- Merge Two Excel FilesFill missing columns in one spreadsheet from another, matched on a shared key.
- Age CalculatorWork out an exact age, or the gap between any two dates.
- Color ConverterConvert between HEX, RGB, HSL, HSV, CMYK and CSS named colors.
- Percentage CalculatorWork out percentages, increases, decreases, discounts and tips.
- Number Base ConverterConvert numbers between binary, octal, decimal, hexadecimal and any base.
- Roman Numeral ConverterConvert numbers to Roman numerals and Roman numerals to numbers.
Image Tools
- Image CompressorShrink JPG, PNG and WebP images in your browser without uploading them.
- QR Code GeneratorCreate permanent QR codes for links, text, Wi-Fi and contact cards.
- Favicon GeneratorTurn an image, letter or emoji into a full favicon set plus the HTML.
AI Tools
Missing a tool?Hang a wish on the wallPopular lookups
- Inches to cm
- Kilometres to miles
- Celsius to Fahrenheit
- GB to MB
- Minutes to hours
- px to rem
- HTTP 404
- HTTP 301
- HTTP 500
- Port 3306
- Port 8080
- Port 443
- 2026 in Roman numerals
- 4 in Roman numerals
- A4 paper size
- Letter paper size
- .heic files
- .webp files
- PNG to JPG
- WebP to PNG
- Cron: every 5 minutes
- chmod 755
- chmod 644
- chmod 777
- /24 subnet
- /16 subnet
- /30 subnet
Reference libraries
- Unit converter337 conversions across length, weight, temperature, volume, data, speed and more.
- Color codes600+ HEX colors with RGB, HSL, CMYK, contrast ratios and matching palettes.
- CSS unitspx, rem, em, pt and more — with an adjustable root font size.
- Time zones94 conversions between EST, PST, UTC, CET, IST, JST and more.
- Image convertersPNG, JPG, WebP, SVG, AVIF and HEIC-adjacent formats, converted locally.
- HTTP status codesEvery code explained — what triggers it and how to actually fix it.
- Cron schedulesReady-made expressions for every common schedule, with next run times.
- Port numbersWhat runs on each port, why it matters, and how to see what is listening.
- File formatsWhat each extension is, what opens it, and what catches people out.
- File permissionsWhat every chmod value grants, and which one is actually right.
- CIDR prefixesEvery subnet size from /0 to /32 with masks and host counts.
- ASCII tableAll 128 codes, with the control characters explained rather than blank.
- Cooking conversionsCups to grams per ingredient — a cup of flour and a cup of honey are not the same weight.
- Roman numeralsEvery number broken down symbol by symbol, plus the rules that govern them.
- Paper sizesA4, Letter, Legal and the rest — in mm, inches and pixels at any DPI.
- Screen resolutions1080p, 1440p, 4K and the rest — aspect ratio, megapixels and PPI.
- Screen sizesTV and monitor dimensions in inches and cm, and what a step up really adds.
- Oven temperaturesGas mark, °C, °F and the fan equivalent — and why the numbers are rounded.
- Bed sizesUS, UK and European mattress dimensions — and why the names do not travel.
- Lumber sizesNominal against actual — a 2x4 is 1½ × 3½ inches, and here is every other board.
- Battery sizesDimensions, voltage and equivalents — and why a CR2032 is called that.
- Wire gaugeAWG in mm, area and resistance — and the formula the whole scale comes from.
- Metric threadsTapping drill, clearance hole and spanner size for M2 to M24.
- Time differencesCity to city, with the weeks each gap is not what every converter says it is.
- Resistor colour codesEvery E24 value both ways — bands to value, value to bands, and the SMD marking.
- Capacitor codes104 is 100 nF. Every three-digit code in pF, nF and µF, with the reactance.
- Tap drill sizesThe drill for every unified thread, and the arithmetic the chart figure comes from.
- Drill sizesNumber, letter and fractional drills in inches and mm, and what each one taps.
- Fastener standardsDIN to ISO, and the three sizes where the same thread takes a different spanner.
- Tyre sizesWhat 205/55R16 measures, which sizes replace it, and the speedometer effect.
- Ring sizesUS, UK and EU conversion — and why the European size is just the measurement.
- Baking tin sizesArea, volume and which tin substitutes for which — and what it does to the time.
- Paper weightGSM to lb — and why 80 lb text and 80 lb cover are different papers.
- Bedding sizesDuvet and comforter dimensions, and how far each hangs over the bed.
- Shoe sizesUS, UK and EU with the foot length each fits — measure first, convert second.
- Door sizesLeaf, rough opening and clear width — three numbers, only one of them the door.
- Sandpaper gritP grades against CAMI grit — P400 is about 320, and here is the whole chart.
- Spanner sizesMetric against imperial — which pairs swap, and which round a bolt head.
- Pipe sizesNPS, DN and the real outside diameter — a half-inch pipe is 0.84 inches.
- Screw sizesGauge to millimetres, and the two different holes a joint needs.
- Brick sizesFormat, coursing and bricks per square metre — where "sixty" comes from.
- Password lengthWhat each length is worth in bits and in time, and where the useful range ends.
- Knitting needlesUS, UK and mm — two scales that run in opposite directions and meet once.