CalcChef tool collection
Developer Tools
Work with JSON, encodings, regex, UUIDs, and developer formats in browser-based utilities.
Start with these tools
JSON Formatter
Paste JSON to format it with 2 spaces, 4 spaces or tabs, minify it or sort its keys. A syntax error is reported with its line, column and a caret under it.
Base64 Converter
Encode text to Base64 or decode Base64 to text. UTF-8, standard and URL-safe alphabets, optional padding on decode, up to 250,000 characters.
Regex Tester
Test a JavaScript regular expression on your own text: every match with its numbered and named groups and start and end positions, flag switches and replace.
UUID Generator
Generate 1 to 1,000 random v4 UUIDs, or time-based v1, or name-based v5 and v3 from a namespace and a name, and copy them. Repeats of v4 are very unlikely.
QR Code Generator
Turn a link, any text of up to 2,000 characters or a Wi-Fi login into a QR code, pick its colors and save it as an SVG or a PNG up to 1,000 px wide.
Binary Converter
Convert text to binary and binary back to text in UTF-8: Hello is 01001000 01100101 01101100 01101100 01101111. A second tab converts whole numbers.
All Developer Tools
74 free browser-based tools
AES Encryption
Encrypt and decrypt text with a password using AES-256-GCM, the key derived by PBKDF2-SHA256 at 600,000 iterations. Strength depends on the password.
API Rate Limit Calculator
Enter an API rate limit, its window in seconds, minutes, hours or days, and the requests used and queued to get percent used, requests left and pacing.
AWS Data Transfer Cost Estimator
AWS data transfer out (egress) cost per month from GB to the internet, other Regions and the same Region, with the 100 GB free tier and volume tiers.
Base58 Address Encoder
Encode hex or text to Base58 or Base58Check and decode it back. Base58Check shows the version byte, the payload and whether the 4-byte checksum matches.
Base64 Converter
Encode text to Base64 or decode Base64 to text. UTF-8, standard and URL-safe alphabets, optional padding on decode, up to 250,000 characters.
Base64 File to String
Encode a file of up to 5 MB to Base64 or a data URI, or decode Base64 back to a downloadable file named from its data URI type or first bytes.
Binary Converter
Convert text to binary and binary back to text in UTF-8: Hello is 01001000 01100101 01101100 01101100 01101111. A second tab converts whole numbers.
Chmod Calculator
Type a chmod mode such as 755 or 4755 to see rwxr-xr-x, or paste rwxr-xr-x or tick read, write and execute for owner, group and public to get the octal number.
CIDR Calculator
Enter an IPv4 CIDR block such as 192.168.1.0/24 for its IP range, netmask, broadcast address and usable hosts, split it into subnets or turn a range into CIDR.
Color Picker
Pick a color or type a HEX, RGB or HSL value to get the other two, the CSS and CMYK forms, and its WCAG contrast ratio on white, black or a second color.
Cron Expression Explainer
Paste a 5-field cron expression or an @alias to read it as one sentence, a card per field and its next runs: 0 9 * * 1 runs at 9:00 AM on Monday.
Cron Job Generator
Type the five cron fields or start from a preset: each box is checked as you type, then read back in plain English with the next 5 run times.
Crontab Translator
Translate a 5-field cron expression into plain English and see the next 5 run times: 0 9-17 * * 1-5 runs hourly from 9 AM to 5 PM, Monday to Friday.
CSS Minifier
Paste CSS to remove comments and unneeded whitespace while keeping descendant spaces, calc() operators and /*! */ license comments, with the characters saved.
CSV to XML
Convert CSV to XML: each row becomes a row element with one child per column, headers become valid XML names, and quoted commas and line breaks are kept.
Data Storage Converter
Convert bytes, KB, MB, GB, TB and bits, with decimal SI units (1 GB = 1,000 MB) kept apart from binary IEC units (1 GiB = 1,024 MiB).
Dockerfile Generator
Generate a Dockerfile from a form: pick a language, base image, ports, env vars, build and start commands, then copy or download the file.
Git Command Builder
Pick a git action such as merge, reset, stash or push, fill in the fields and copy the command, quoted for the shell, with warnings for risky flags.
GraphQL Query Builder
Test a GraphQL query in the browser: send it with variables and headers, pick fields from the introspected schema, read the response and copy it as cURL.
Hash Generator
Compute the MD5, SHA-1, SHA-256, SHA-384 or SHA-512 hash of text or a file and compare it with an expected checksum. The file is hashed in your browser.
Hex to Decimal
Convert hex to decimal, binary or octal with exact whole-number math: FF is 255. Pads hex to 8, 16, 32 or 64 bits and converts 200 lines at once.
Hex to RGB Color Converter
Type a hex color code such as #1E90FF or the short #F80 to get its RGB and HSL values: #1E90FF is rgb(30, 144, 255) and hsl(210, 100%, 56%).
HMAC Generator
Compute an HMAC with SHA-1, SHA-256, SHA-384 or SHA-512 and check it against a signature, with webhook presets for GitHub, Stripe, Shopify and Slack.
HTML Entity Encoder
Encode text to HTML entities (& < > " ') or decode any of the 2,231 named references in the HTML standard and numeric ones such as é.
HTML Minifier
Paste HTML to drop comments and collapse whitespace. The space between inline elements stays, pre and textarea are kept, and inline CSS and JS can be minified.
HTML Sanitizer
Sanitize pasted HTML at Strict, Moderate or Permissive level: scripts, event handlers and javascript: links are removed, and the tool lists what it took out.
HTTP Headers Viewer
See the request headers an echo service (httpbin.org) receives from one fetch by this page, or by your own URL. Copy as cURL, fetch(), Python or .env.
IP Address Viewer
See the public IP address your connection uses, with the approximate city, region, country and provider from ipapi.co, or look up any IPv4 or IPv6 address.
JS Minifier
Paste JavaScript to remove comments and unneeded whitespace. Line breaks the code relies on and /*! license comments stay; variable names are not shortened.
JS Object to JSON Converter
Paste a JavaScript object or array literal and get JSON. Unquoted keys, single quotes and trailing commas are accepted, and no code is run.
JSON Diff
Compare two JSON documents side by side or as a list of paths, such as $.name changed from "John" to "Jane". Key order is ignored; numbers compare exactly.
JSON Formatter
Paste JSON to format it with 2 spaces, 4 spaces or tabs, minify it or sort its keys. A syntax error is reported with its line, column and a caret under it.
JSON Path Query Tool
Test a JSONPath expression on your JSON and see the match count, each matching value and its path. Filters such as ?(@.price < 10) work. Up to 100 KB.
JSON to SQL
Generate SQL INSERT statements, and CREATE TABLE if you want it, from JSON for PostgreSQL, MySQL, SQLite or SQL Server, with types inferred from every row.
JSON to YAML
Convert JSON to YAML in block or flow style. Text such as yes or 017 is quoted so it stays a string, and a JSON error shows its line and column.
JSON Validator & Auto-Repair
Check JSON for syntax errors and repair comments, single quotes, unquoted keys and trailing commas. Values stay as typed; errors show your line and column.
JWT Expiration Checker
Decode a JWT and compare its exp, nbf and iat claims with your clock to see Expired or Not expired and the time left. The signature is not verified.
Keycode Checker
Press a key to see its event.key, event.code, location and modifiers, plus the deprecated keyCode and which numbers: Enter is 13, Space 32, A to Z 65 to 90.
Latency Percentile Calculator
Paste latency samples in milliseconds for p50 to p99.9 by interpolation or nearest rank, plus mean, standard deviation and median-based outliers.
Lorem Ipsum Generator
Generate lorem ipsum placeholder text as paragraphs, sentences or words, up to 100 paragraphs or 5,000 words, with optional HTML paragraph tags.
Markdown Table Generator
Type cells in a grid or paste from a spreadsheet to get a padded Markdown pipe table with left, center or right alignment, plus HTML and CSV copies.
Markdown to HTML
Convert Markdown to HTML with GitHub tables, task lists and strikethrough. Raw HTML shows as text except 17 plain tags; javascript: links become text.
Number Base Converter
Convert a whole number between binary, octal, decimal and hexadecimal and see all four at once: 255 is 11111111, 377 and FF.
Password Entropy Calculator
Estimate password entropy as length × log₂(pool size) and average crack times at three guess rates. Common passwords and patterns are rated Very Weak.
Password Generator
Generate a random password of 8 to 128 characters from uppercase, lowercase, numbers and symbols, and see its entropy in bits. Can skip look-alike characters.
PBKDF2 Calculator
Derive a PBKDF2 key in hex or Base64 from a password and salt with HMAC-SHA-1, SHA-256, SHA-384 or SHA-512, and check it against a key you paste.
QR Code Generator
Turn a link, any text of up to 2,000 characters or a Wi-Fi login into a QR code, pick its colors and save it as an SVG or a PNG up to 1,000 px wide.
Random Data Generator
Generate 1 to 1,000 fake people as JSON, CSV or a SQL INSERT: id, name, email, phone, address, age and active, each optional but id. Seeds repeat rows.
React Component Boilerplate
Generate a React function or class component in TypeScript or JavaScript with the hooks you tick, typed props, React.memo or "use client", as a starting point.
RegEx Playground
Try 11 regex presets, from email, phone and IPv4 to semver and hex color, on sample text, see every match, and read what each pattern does not check.
Regex Tester
Test a JavaScript regular expression on your own text: every match with its numbered and named groups and start and end positions, flag switches and replace.
RGB to Hex
Convert RGB to a hex color code and back: rgb(255, 136, 0) is #FF8800. Paste #abc, ff8800 or 255,136,0; each channel is a whole number 0 to 255.
Shell Commands Cheat Sheet
Search or filter 83 common shell commands by level, topic and platform, and copy a name or example. 12 are tagged as Linux tools or not on a default Mac.
Slug to Pascal Case Converter
Convert a slug, kebab-case, snake_case or camelCase name to PascalCase, camelCase, CONSTANT_CASE and four other forms: user-profile-card is UserProfileCard.
SQL Query Formatter
Format SQL for Standard SQL, PostgreSQL, MySQL, SQLite or SQL Server, with keywords kept, upper-cased or lower-cased and 2-space, 4-space or tab indents.
SQL to JSON
Turn SQL INSERT statements, or a result table pasted from psql, MySQL or Markdown, into JSON. Quoted values stay strings; numbers, true and NULL get types.
Subnet Mask Calculator
Subnet calculator for IPv4: enter an address and a mask or prefix such as /24 to get the network, broadcast address, host range, usable hosts and wildcard mask.
Subnet Mask Cheat Sheet
Subnet mask table for every IPv4 prefix from /0 to /32: dotted mask, wildcard, total and usable hosts, with /31 counted as 2 (RFC 3021) and /32 as 1.
SVG Code Viewer
Paste SVG code to preview it as an image with scripts, event handlers and outside links removed, list its colors and elements, minify it or export React TSX.
SVG to CSS Background Converter
Convert SVG markup to a CSS background-image data URI, URL-encoded or Base64. Adds a missing xmlns, rejects non-SVG input, gives url() or inline-style output.
Text Diff Tool
Text diff tool that compares two texts by line, word or character and marks what was added and removed. It can ignore whitespace, case and line endings.
Text Encryptor and Decryptor
Encrypt or decrypt text with a password using AES-256-GCM and a PBKDF2-SHA-256 key of 600,000 iterations. The password cannot be recovered if lost.
ULID Generator
Generate 1 to 500 ULIDs, 26-character IDs that sort by creation time, in upper or lower case, and decode any ULID to the date it was made.
Unicode Lookup
Look up any character or code point such as U+1F600: its name, category, script, block and UTF-8, UTF-16 and UTF-32 bytes, or search names and browse blocks.
URL Encoder/Decoder
Percent-encode or decode text as you type: one value with encodeURIComponent or a whole URL with encodeURI, and an option to read + as a space.
User Agent Parser
Paste a User-Agent string to read the browser, engine, OS and version, device type and model, CPU hints or the crawler it names, with notes on frozen values.
UUID Generator
Generate 1 to 1,000 random v4 UUIDs, or time-based v1, or name-based v5 and v3 from a namespace and a name, and copy them. Repeats of v4 are very unlikely.
UUID v7 Generator
Generate 1 to 1,000 UUID v7 values that stay in creation order on one page, and decode a UUID to its version, variant and timestamp.
VPN Data Savings Estimator
Estimate VPN data use with assumed compression ratios for LZ4, LZO and Zstd plus a 5% tunnel overhead. The ratios are scenarios, not measurements.
XML Formatter
Format or minify XML with 2 spaces, 4 spaces or tabs. Comments, CDATA, DOCTYPE, attribute values and mixed content stay as written, up to 300,000 characters.
XML to JSON Converter
Convert XML to JSON and JSON back to XML: attributes go under @attributes, repeated elements become arrays, and an XML error shows its line and column.
YAML to JSON Converter
Convert YAML to JSON with anchors and merge keys resolved, YAML 1.2 or 1.1 typing for yes/no, and a warning for numbers JSON cannot hold.
YAML Validator
Check YAML syntax as you type: line and column of the first error, a JSON view of each document, unknown tags such as !Ref listed, << merge keys optional.
Z-Index Stacking Context Debugger
Check which CSS properties make an element a stacking context (position, z-index, opacity, transform, isolation) and where its z-index counts.