Developer & Text Tools

239 tools · page 2 of 4

• 🔢Verhoeff Checksum Validator Validate a number's Verhoeff check digit (used by Aadhaar) and show the correct one.
• 🔐Gronsfeld Cipher Encoder/Decoder Encode or decode text with the Gronsfeld cipher — a Vigenère variant that shifts each letter by the digits of a repeating numeric key.
• 📂Unix Permissions (chmod) Calculator Convert a Unix file permission (e.g. 755) into the readable rwx symbol and owner/group/others rights.
• 🔐Affine Cipher Encrypt or decrypt text with the Affine cipher using keys a and b (a must be coprime with 26).
• 🔐Password Entropy Calculator Estimate password strength in bits of entropy from length and character set.
• 🖥️Resolution Scaler Scale a resolution to a new width while keeping the aspect ratio, and see the simplified ratio.
• 📖SMOG Index Calculator Calculate the SMOG readability grade of English text from its polysyllabic words and sentences.
• 🎤Speech Time Calculator Estimates speaking time from a word count and your speaking pace, helpful for speeches, presentations and voiceovers.
• 🔁Text Diff Tool Compares two blocks of text and reports how many lines were added, removed and unchanged, plus the character-level edit distance.
• 🔤Leetspeak Translator Convert normal text to leetspeak (1337) or back using a standard substitution map.
• 🔗Join Lines Tool Merge multiple lines of text into a single line.
• 📚ISBN Check Digit Calculator Compute the ISBN-13 check digit for the first 12 digits and validate a full 13-digit ISBN.
• 🟢Uptime SLA Calculator Calculate the allowed downtime per year, month and day for a given uptime SLA percentage.
• 🌗Color Contrast (WCAG) Checker Calculate the WCAG contrast ratio and AA/AAA compliance from a foreground and background color.
• 📐CSS Clamp Generator Create a responsive CSS clamp() function for fluid font sizes. Enter your minimum and maximum font sizes in pixels along with the viewport range, and get a ready-to-paste clamp() rule that scales smoothly between breakpoints using rem and vw units.
• 🔤Pangram Checker Checks whether a sentence is a pangram by testing if it contains every letter of the English alphabet, and lists any missing letters.
• 🔣HTML Entity Encoder Encode special characters in text (&, <, >, quotes) as safe HTML entities so they display literally in a page. Copy the result with one click.
• 🔢Luhn Checksum Calculator Validate a number with the Luhn (mod 10) algorithm, or compute the check digit that makes a number valid.
• 💠Card BIN Format Checker Detects the card network from the BIN/IIN prefix and checks whether the number length and Luhn checksum are valid.
• 🏷️LEI Validator Validates a 20-character Legal Entity Identifier (LEI) using the ISO 17442 / mod-97-10 (ISO 7064) check-digit algorithm.
• ␣Collapse Whitespace Tool Replaces every run of spaces, tabs, and line breaks with a single space and trims the result.
• 🔠em to Pixel Converter Convert CSS em units to pixels at a chosen base font size (px = em × base). Essential for responsive typography.
• 🔐One-Time Pad XOR Tool Encrypts text to hex or decrypts hex back to text by XOR-ing each byte with a repeating key.
• 🔐HMAC-SHA256 Generator Generates an HMAC-SHA256 message authentication code from a message and secret key, in hexadecimal and base64.
• 🚧Rail Fence Cipher Encrypt or decrypt text with the Rail Fence transposition cipher over a chosen number of rails.
• 🙃Upside Down Text Generator Turn your text upside down using Unicode look-alike characters, so it reads flipped. Fun for social media bios, usernames and messages. Copy the result with one click.
• 🏷️GS1 Prefix Check Calculator Validates a GS1 GTIN / barcode by recomputing its check digit and shows the company prefix block.
• 📖Gunning Fog Index Calculator Calculate the Gunning Fog readability index and grade level of English text.
• 🔐Hill Cipher Encoder/Decoder Encodes or decodes A–Z text with a 2×2 Hill cipher key matrix using arithmetic modulo 26.
• 🔤UTF-8 Byte Encoder Encodes text to UTF-8 and shows the byte length, hex bytes and per-codepoint breakdown.
• ⠿Braille (Grade 1) Translator Translates English text to uncontracted (Grade 1) Unicode Braille and decodes Braille dot patterns back to text.
• 🔐ElGamal Encryption Calculator Demonstrates ElGamal public-key encryption: derives the public key and encrypts an integer message into the ciphertext pair (c₁, c₂).
• 🧽Remove Extra Spaces Collapse repeated spaces and tabs to a single space and trim each line.
• 📚ISBN Validator Validate an ISBN-10 or ISBN-13 number and compute its correct check digit.
• 🔤Line Sorter Tool Sorts a list of lines alphabetically or numerically, with optional duplicate removal.
• 🔐RSA Private Exponent Calculator Computes the RSA private exponent d as the modular inverse of the public exponent e modulo Euler's totient φ(n).
• 💻Bit Shift Calculator Performs a bitwise left or right shift on an integer and shows the result in decimal, hexadecimal and binary.
• 🔤Character Frequency Counter Count how often each character appears in a text (ignoring whitespace), ranked from most to least frequent, with totals. Useful for cryptanalysis, writing analysis and puzzles.
• 🔱Egyptian Fraction Decomposer Decompose a proper fraction into a sum of distinct unit fractions using the greedy (Fibonacci–Sylvester) algorithm.
• 🔢Sort Lines Numerically Tool Sort lines of text in ascending order by the number each line starts with — handy for logs, measurements and exported data where plain alphabetical sorting puts 100 before 9. Copy the sorted result with one click.
• 🌐IPv4 to Hex Converter Convert a dotted-decimal IPv4 address to its hexadecimal and 32-bit decimal forms. Handy for networking and low-level work.
• 📖Lexical Density Calculator Measures lexical density, the percentage of content words in a passage of text.
• 🖋️Pixel to Point Converter Converts CSS pixels to typographic points and picas using the standard 96px-per-inch reference.
• 🔀Endianness Swap Calculator Swap the byte order (endianness) of a hexadecimal value between big- and little-endian, with the decimal equivalent.
• 🔬Float to Hex Bits Converter Convert a number to its raw IEEE-754 hexadecimal bit pattern in both single (32-bit) and double (64-bit) precision. Useful for low-level debugging and understanding floating-point representation.
• 🖥️Server Energy Cost Calculator Estimates the daily, monthly, and yearly electricity cost and energy use of a home server or always-on device from its power draw and your kWh price.
• 🔐Base64 String Validator Validates whether a string is well-formed standard Base64 and reports its decoded byte length.
• 🔗Percent-Encoding (RFC 3986) Tool Percent-encodes or decodes text following RFC 3986, escaping every character except the unreserved set A-Z a-z 0-9 - . _ ~.
• 🔤Unique Word Counter Count the total and distinct (unique) words in any text, along with the lexical diversity ratio. Useful for writers, students and editors checking vocabulary richness and repetition.
• 🇮🇹Codice Fiscale Validator Validate a 16-character Italian Codice Fiscale by checking its format and recomputing the control character.
• 🧮CRC-16/CCITT Checksum Calculator Compute the CRC-16/CCITT-FALSE checksum (polynomial 0x1021, init 0xFFFF) of hexadecimal data, common in serial protocols.
• 🔑SipHash-2-4 Calculator Compute the SipHash-2-4 64-bit keyed hash of any text using a 16-byte (32 hex) key. Returns a 16-character hexadecimal digest.
• ⌨️Typing Time Calculator Estimate how long it takes to type a number of words, or a pasted text, at your words-per-minute speed.
• 😀Emoji Unicode Codepoint Lookup Convert any emoji or character to its Unicode codepoints (U+XXXX), or turn U+ codepoints back into emoji. Works in both directions.
• 🆔ISNI Validator Validates a 16-character ISNI using the ISO 7064 MOD 11-2 check digit algorithm and shows the computed check character.
• 🖥️Points to Pixels Converter Convert typographic points to CSS pixels at 96 dpi (1 pt = 1.333 px). Useful for translating print type sizes to the web.
• 🔄Reverse Words Tool Reverse the order of words in a sentence.
• 🧹Remove Blank Lines Tool Remove all empty and whitespace-only lines from a block of text and see how many lines were removed and kept.
• 🎨RGB to HSL Converter Converts an RGB color (0-255 channels) to its HSL equivalent and shows the hex code.
• 🎨RGB to LAB Converter Converts an sRGB hex color to CIELAB (L*a*b*) coordinates using the D65 white point for color matching and print work.