Free tools that respect your time, your data, your language.

Free online Base64 encoder and decoder. UTF-8 safe, works offline, runs entirely in your browser.

Encode and decode URL components per RFC 3986. UTF-8 safe, runs in your browser.

Inspect JSON Web Tokens in your browser. Header, payload, expiry. No key required, no data sent.

Generate UUIDs v4, v7, and v1 in the browser. Sortable v7 recommended for database keys.

Compute MD5, SHA-1, SHA-256, SHA-384, SHA-512 hashes of text or files. Hex or Base64 output. Browser-only.

Generate strong passwords with crypto-grade randomness. Length, charsets, ambiguous-char filter. Browser-only.

Convert between Unix seconds, milliseconds, ISO 8601, and timezone-aware human dates.

Format, minify, sort, and validate JSON. JSON5 mode accepts comments and trailing commas. Browser-only.

Format SQL across 10 dialects (Postgres, MySQL, SQLite, BigQuery, Snowflake, T-SQL, PL/SQL, …). Browser-only.

Test JavaScript regex patterns against any text. Capture groups, named groups, flags, replace mode. Browser-only.

Free BMI calculator with metric + imperial units. Shows category from underweight to obese class III. For estimation only.

Quick tip calculator with bill splitter. Set tip percentage, number of people, see per-person amount instantly.

Calculate exact age in years, months, days, hours, and minutes from a birth date.

Three modes: X% of Y, X is what % of Y, % change from X to Y. Discounts, taxes, grades, growth rates.

Calculate cumulative GPA on the US 4.0 scale. Add courses with grade and credit hours, get weighted average.

Calculate compound interest over time with monthly contributions. See final balance, total interest, total contributions.

HEX ↔ RGB ↔ HSL color converter with WCAG AA/AAA contrast checker. For designers and accessibility audits.

Convert length, weight, temperature, volume, and speed between metric and imperial units.

Convert text between camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE and 8 more. Browser-only.

Turn any text into URL-safe slug. Handles Vietnamese diacritics, German ß, French accents, emoji.

Encode/decode HTML entities (&, <, >, named, numeric, hex). Full HTML5 entity set.

Generate realistic mock data (users, emails, addresses, dates) as JSON, CSV, or SQL. 7 locales.

Convert between JSON, YAML, and TOML. Auto-detect input format. Browser-only.

Convert between CSV and JSON. Auto-detect delimiter, quote handling, header row toggle. Browser-only.

Convert Markdown to HTML and back. GFM (tables, task lists) supported. Browser-only.

Compare two texts character/word/line. Generate unified patch. Browser-only.

Convert curl commands to fetch, axios, Node, Python, PHP, Go. Browser-only.

Parse cron expressions to human language. See next 10 scheduled runs. Browser-only.

Convert a time between IANA timezones. Meeting planner across continents. Browser-only.

Format, minify, and validate XML. Preserves attributes, namespaces, CDATA. Browser-only.

Format, validate, sort keys in YAML. Browser-only.

Generate placeholder text — classic Lorem Ipsum, Vietnamese filler, Spanish, or hipster style. Words, sentences, paragraphs, or HTML.

Pretty-print or minify HTML with configurable indent, attribute wrapping, and self-closing handling. 100% local.

Pretty-print or minify CSS with configurable indent, selector separator, and brace style. 100% local.

Pretty-print or minify JavaScript with real AST. Beautify via js-beautify, minify via Terser. ES2024 syntax supported.

Convert text to and from hexadecimal bytes. UTF-8 safe — handles emoji, Vietnamese, CJK. Configurable separator and 0x prefix.

Convert text to and from 8-bit binary. UTF-8 safe. Configurable byte separator.

Convert text to \uXXXX or \u{XXXXX} escapes and back. Handles surrogate pairs for emoji. Output JSON-safe or ES2015 syntax.

Basal Metabolic Rate calculator using the Mifflin–St Jeor equation. Daily calorie burn at complete rest.

Daily calorie target calculator. BMR (Mifflin–St Jeor) × activity factor × goal adjustment. Returns TDEE and weight goal calories.

US Navy method body fat % from waist, neck, height (and hip for women). Quick estimate without calipers.

Compute pace from distance + time, or predict time from pace + distance. Min/km, min/mile, common race distances.

Calculate years, months, days, weeks between two dates. Handles leap years and short months correctly.

Original price + discount % → final price + amount saved. Optionally stack a sales tax.

Optimal bedtimes for waking refreshed. Based on 90-minute REM cycles + 14-minute fall-asleep average.

Count words, characters (with/without spaces), sentences, paragraphs. Live updates. Tweet-length tracker built in.

Estimate reading and speaking time from text. Adjustable WPM for different audiences.

One screen for all random picks: dice roll, coin flip, random number range, pick from a list.

Monthly payment + total interest from loan amount, rate, and term. User-input rate (no live rate fetch).

Monthly payment + interest for auto, personal, student loans. Amortization preview.

Expression-based scientific calculator. Trig, log, exp, factorial, constants. Keyboard-friendly.

Paste a list of numbers, get mean, median, mode, range, variance, standard deviation, quartiles.

Generate harmonized palettes: analogous, complementary, triadic, monochromatic. From a single seed color.

Convert between 30+ currencies. Rates from Frankfurter (ECB) cached 24h. Free, no API key needed.

Validate Ethereum (EIP-55), Bitcoin (legacy/segwit/bech32), and Solana addresses. Browser-only, no blockchain queries.

Convert between Ethereum units (wei, gwei, ether, etc.). BigInt math, no precision loss.

Generate QR codes for text, URLs, vCard, Wi-Fi, or email — PNG and SVG download, error correction levels, color customization. 100% local.

Convert images between PNG, JPEG, and WebP in your browser. Quality slider for lossy formats. AVIF input supported (decode). Max 10 MB. 100% local.

Add or remove sales tax from a price. Configurable rate. No tax tables — bring your own rate.

Project retirement balance from current savings, monthly contribution, return rate, and retirement age.

What do I need on the final? Given current grade + final weight + target grade, calculate the required score.

Estimated due date from last menstrual period (Naegele's rule, 40 weeks). For information only — not medical advice.

Sum daily work hours from clock-in/clock-out times, subtract unpaid breaks. Weekly total + pay.

Solve a triangle: three sides → angles + area (Heron). Pythagorean check for right triangles.

Convert shoe sizes across US, EU, UK, and JP (cm). Men, women, kids. Approximate — brands vary.

Flesch Reading Ease + Flesch-Kincaid Grade Level + Gunning Fog. English text only.

Convert nightly tips + base wage + hours worked into effective hourly rate. For service workers.

25-minute focus blocks with 5-minute short breaks and 15-minute long breaks. Audio cue via Web Audio oscillator.