🔁 変換・エンコード

Use our free online Base64 encoder and decoder to convert between plain text and Base64-encoded strings. Base64 encoding is widely used for embedding images in HTML/CSS, transmitting binary data over text-based protocols, and storing data in JSON. Our tool processes everything locally in your browser — no data leaves your device.

Convert between data size units — Bytes, Kilobytes, Megabytes, Gigabytes, Terabytes, and Petabytes. All conversions use the binary (1024) system standard for computing.

Generate a palindrome by appending your text to its reverse.

Turn a URL slug back into a human-friendly title.

Detect hidden, zero-width, and invisible Unicode characters.

Convert HTML special characters to entities and back in your browser.

Convert between HTML and Markdown formats in your browser.

Normalize a date or time into ISO 8601 format.

Join multiple lines of text into one string.

Escape a raw string into a valid JSON string literal.

Stringify JSON with your preferred formatting.

Write Markdown and see live HTML preview in real time.

Encode text into International Morse Code or decode Morse back to text.

Convert between binary, octal, decimal, and hexadecimal.

Check if your text reads the same forwards and backwards.

Generate a formatted quote with an optional author.

Randomly mix uppercase and lowercase letters.

Strip redundant whitespace from your text in one click.

Copy the same text multiple times and join them with a separator of your choice.

Reverse text at the character, word, or line level.

Convert between Arabic numbers and Roman numerals right in your browser.

The classic ROT13 substitution cipher. Apply it twice to decrypt.

Generate clean, SEO-friendly URL slugs from any text. Our slug generator strips special characters, normalizes Unicode (so "café" becomes "cafe"), converts spaces to hyphens, and produces search-engine-optimized URLs ready to use. Batch-process multiple lines at once for blog posts, product pages, or database records.

Split a single string into multiple lines by delimiter.

Compare two text blocks and see the differences line by line.

Perform fast find-and-replace operations on any text. Whether you need to fix typos across a long document, update URLs in a batch of links, or rename variables in code, our text replacer handles it all in your browser. Supports case-sensitive matching, whole-word matching, and batch multi-line replacement.

Turn any text into spoken audio using your browser’s speech synthesis.

Truncate a string to a given character or line count.

Convert Unicode characters to numeric HTML entities and back.

Convert percent-encoded URLs back to readable text.

Turn any string into a URL-safe percent-encoded format.

Split any URL into its component parts.

Identify browser, OS and device from a User-Agent string.

Our free online duplicate line remover helps you clean up messy text lists instantly. Whether you have a shopping list with repeated items, a CSV export with duplicate rows, or a log file with repeated entries — paste your text, choose a removal mode, and get a deduplicated result in seconds. Everything runs locally in your browser; nothing is uploaded to any server.

Break down a URL into its component parts.