無料オンラインツール集 —
96種類

Use free AI to summarize, extract, rewrite, or translate any text. Powered by Puter.js — no server, no API key needed.

Analyze text sentiment entirely in your browser using Transformers.js.

Detect the language of any text using free AI.

Add Chinese comments to your code automatically using AI.

Auto-classify text into topic, tone, audience, sentiment and language labels.

Extract named entities — people, places, dates, organizations — from any text.

Remove AI-generated sounds and make text sound more human.

Extract all tasks and action items from any text.

Extract all contact info — emails, phones, URLs — from any text.

Merge multiple PDFs into one file.

Split PDFs and extract specific pages.

Compress PDFs to reduce file size.

Pick a color and convert Hex, RGB, HSL instantly.

Create CSS gradients with live preview.

Create CSS box-shadow with live preview.

Look up any IP or your own — see location, ISP, and more.

Test regex patterns against any text and see all matches with their positions.

Generate SHA hashes for any text using the browser Web Crypto API.

Decode any JWT into its header and payload for inspection.

Write Markdown and see live HTML preview in real time.

Generate QR codes from any text or URL entirely in your browser.

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.

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.

Generate strong, cryptographically secure random passwords right in your browser. Customize the length (up to 256 characters), choose which character types to include (lowercase, uppercase, numbers, symbols), and optionally avoid ambiguous characters like 0/O/l/I. Our password generator uses the Web Crypto API for maximum randomness — and everything runs locally, so your passwords are never transmitted.

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.

Our free online word counter gives you instant statistics on any text: total words, characters (with and without spaces), sentences, paragraphs, and estimated reading time. Perfect for blog writers, students, and marketers who need to hit specific word count targets. Everything is calculated locally in your browser in real time.

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.

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

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

Convert percent-encoded URLs back to readable text.

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

Convert Unicode characters to numeric HTML entities and back.

Truncate a string to a given character or line count.

Pull out all email addresses from a block of text.

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

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

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

Generate a formatted quote with an optional author.

Randomly mix uppercase and lowercase letters.

Join multiple lines of text into one string.

Split a single string into multiple lines by delimiter.

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

Check if your text reads the same forwards and backwards.

Change the letter case of your text in multiple ways.

Hide sensitive words in text with a chosen mask character.

Generate a palindrome by appending your text to its reverse.

Cut out a portion of text by position or pattern.

Break down a URL into its component parts.

Format, beautify, minify, and validate JSON data in one tool. Paste your raw JSON and we'll pretty-print it with proper indentation, validate its structure, highlight any syntax errors, and let you copy or download the result. Essential for developers working with APIs, configuration files, and data interchange. All processing runs locally in your browser.

Check whether your JSON data is valid and well-formed. Our validator catches common syntax errors — missing commas, unquoted keys, trailing commas, mismatched brackets — and pinpoints the exact line where the error occurs. Perfect for debugging API responses, config files, and data exports.

Escape a raw string into a valid JSON string literal.

Sort the keys of any JSON object alphabetically, recursively.

Stringify JSON with your preferred formatting.

Turn a JSON array into a properly quoted CSV file.

Convert between binary, octal, decimal, and hexadecimal.

Convert currencies at live exchange rates.

Convert hourly wage to annual/monthly/daily salary.

Calculate loan payments and amortization schedule.

See how compound interest grows your money over time.

Calculate BMI and see your health category.

Generate one or more UUID v4 (GUID) identifiers with cryptographic randomness.

Quickly calculate the sum of any list of numbers. Paste numbers (one per line, comma-separated, or space-separated) and get instant results including total sum, count, average, minimum, and maximum values. Great for quick mental math, spreadsheet verification, and tallying.

Generate cryptographically secure random numbers within any range. Set minimum, maximum, count, and optionally exclude duplicates. Uses the Web Crypto API for maximum randomness.

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

Spell out a number in English words.

Generate an arithmetic (linear) sequence.

Get a random network port number in the valid range.

Check weather for any city with current and 3-day forecast.

Convert Unix timestamps (epoch time) to human-readable dates, or convert dates to Unix timestamps. Supports seconds, milliseconds, and microseconds precision. Also shows your current local time as a Unix timestamp. Essential for developers working with APIs, databases, and logging systems that store time as epoch values.

Convert any number of seconds into a readable time format — days, hours, minutes, and seconds. Useful for video editing, game timing, audio production, and understanding Unix-style durations.

Convert time in HH:MM:SS format to a decimal hours value. Essential for payroll calculations, invoicing, and timesheet management where hours need to be expressed as a single decimal number.

Quickly convert a number of hours into days and remaining hours. Useful for project planning, scheduling, and understanding long durations.

Convert any number of days into the equivalent number of hours. A simple time conversion tool for planning and calculations.

Check whether any year is a leap year. Enter one or multiple years (comma or space separated) and get instant results. Leap years have 366 days and occur every 4 years, with exceptions for century years.

Find out what day of the week any date falls on. Enter dates in any format (YYYY-MM-DD, MM/DD/YYYY, etc.) — one per line or comma separated — and get instant results.

Calculate the exact difference between two dates and times. Get the result in days, hours, minutes, seconds, and approximate months. Useful for age calculation, project timelines, and countdowns.

Convert dates to Discord's embeddable timestamp format.

Interpret a 5-field cron schedule expression.

Sort any list of items — text lines, numbers, or mixed content. Choose alphabetical, numeric, or by-length sorting, in ascending or descending order. Paste items separated by newlines, commas, or tabs.

Instantly reverse the order of any list of items. The first line becomes the last, the last becomes the first. Simple, fast, and entirely in your browser.

Randomly shuffle any list of items. Perfect for drawing lots, randomizing the order of names, and breaking up predictable sequences.

Remove duplicate entries from a list and keep only unique values. Optionally enable case-insensitive mode to treat "Apple" and "apple" as the same item.

Identify duplicate entries in any list and see how many times each duplicate appears. Useful for data cleanup, audit, and analysis.

Unwrap and clean up formatted lists by removing bullet prefixes (-, *, •) and joining wrapped lines into clean single entries.

Add bullet points, dashes, asterisks, or numbered prefixes to each line of your list. Choose the bullet style and get a formatted list instantly.

Trim a list to a limited number of lines.

Organize key=value lines into groups.

Multiply each line of your list.

Find which lines appear most often in your text.

Convert CSV (Comma Separated Values) data to JSON format. Supports quoted fields, commas within values, and uses the first row as headers. Perfect for data import, API preparation, and ETL workflows.

Change the delimiter of CSV data.

Convert comma-separated CSV to tab-separated TSV.

Turn a CSV string into well-formed XML.

Transpose (rotate) a CSV table — rows become columns.

Format raw XML with readable indentation.

Validate whether your XML is well-formed.