Practical utilities for developers and engineers.
Convert between bits, bytes, and transfer speed units.
Estimate how long a file will take to download at a given connection speed.
Parse, format, and validate JSON, YAML, XML, and HTML. All processing happens in your browser.
Test regular expressions against sample text. See matches and capture groups.
Generate UUID v4, ULID, or Nanoid; or paste one to validate and decode (ULID shows timestamp).
Convert between Unix timestamps and dates. Show relative time and epoch ranges.
Parse cron expressions and see the next run times in plain language.
Generate random passwords and check the strength of any password. All input stays in your browser.
Build a Content-Security-Policy header from common directives.
Paste CORS response headers, check for issues, and get recommended headers for origin whitelisting.
Enter a CIDR or IP and mask to see network, broadcast, and usable host range.
Paste a URL to see its components: scheme, host, path, query, and fragment.
Convert between binary, octal, decimal, hex, and other bases (2–36).
Convert between HEX, RGB, and HSL. Preview the colour.
Add or subtract days, weeks, months, or years from a date. Or compute the difference between two dates.
Convert strings between 18 formats including Base64, Base32, Base58, URL, HTML, JSON, Hex, Binary, ASCII85, UUencode, Morse Code, NATO Phonetic, Braille, and more.
Convert between centimetres, metres, inches, and feet.
Encrypt and decrypt text using 26 classical and modern ciphers including AES-GCM, AES-CBC, Caesar, Vigenère, Playfair, Bifid, Affine, XOR, Rail Fence, and more.
Generate cryptographic and non-cryptographic hashes using 12 algorithms including SHA-256, SHA-3, MD5, CRC32, and more.
Decode, verify, and create JSON Web Tokens with support for HMAC, RSA, RSA-PSS, and ECDSA algorithms.
Convert between mph, km/h, m/s, knots, and ft/s.
Convert between bar, psi, kPa, atm, mmHg, and inHg.
Convert between joules, kWh, Wh, MWh, calories, and eV.
Convert between degrees, radians, and gradians.
Convert power (W, kW, hp, BTU/h) and energy (J, Wh, kWh, eV).
Encode a URL or text into a QR code image. All input stays in your browser.
Paste a PEM certificate or CSR to see subject, issuer, validity, and extensions. All processing in your browser.
Generate barcodes in UPC-A, EAN-13, Code 128, and other formats. Renders in your browser.
Convert between decimal degrees and degrees–minutes–seconds (DMS). No geocoding or external APIs.
Luhn check-digit validation for numeric strings (e.g. card numbers) and IBAN validation/formatting. No external API.
See how Gravatar resolves an email to an avatar. Only the hash is computed; the email never leaves your device.
Compound interest (AER), savings growth, and loan amortization with breakdowns. For illustration only; not financial advice.