All Tools
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Character Counter
Real-time character, line, and manuscript page counter. Perfect for reports, essays, and blog posts. Free tool with options to include/exclude line breaks and spaces.
Date Calculator
Free date calculator for period calculation and date arithmetic. Supports leap years. Calculate dates after/before a specific date or find the period between two dates instantly.
Tax Calculator
[2024 Edition] Calculate 10% and 8% (reduced rate) consumption tax at once. Easy conversion between tax-inclusive and tax-exclusive prices. Free simulator for invoice system verification.
QR Code Generator
Generate high-quality QR codes instantly from URLs or text. Download as images. Perfect for events, business cards, and flyers.
Address Label Maker
Easily create address labels for Japanese envelopes. Print on white paper and affix to envelopes. Supports Naga-3 and Kaku-2 envelope sizes, horizontal writing only.
Seasonal Greetings & Kigo
Search seasonal greetings for letters and emails by month and period. Essential for Japanese business correspondence and seasonal greetings. Based on 24 solar terms and haiku kigo.
Password Generator
Generate strong and secure random passwords. Customize length and character types, create multiple passwords at once. Simplify account creation instantly.
URL Encoder/Decoder
Safely encode and decode URLs with Japanese characters and special symbols. Essential for web development, API integration, and link sharing. Real-time conversion support.
Online Notepad
Free online notepad for your browser. Auto-save feature with character count, download, and print support. No registration required.
Text Formatter
Batch process text line breaks (CRLF/LF), remove spaces, convert between full-width and half-width characters. Convenient free tool for text formatting and cleanup.
Color Converter
Convert between HEX, RGB, and HSL color codes. Pick a color to get all format codes instantly. Essential free tool for web design and development.
Markdown to HTML Converter
Convert Markdown to HTML instantly. Real-time preview with CommonMark support. Perfect for blog articles and technical documentation creation.
Japanese Calendar Converter
Convert between Western calendar and Japanese era names (Reiwa, Heisei, Showa, Taisho, Meiji) instantly. Free tool with reference chart for birthdate verification and document creation.
Age Calculator
Calculate current age from birth year instantly. Supports both Western and Japanese calendars, displays school grade and zodiac sign. Useful for resume creation and age verification.
Loan Repayment Simulator
Easily simulate mortgage and auto loan repayments. Supports both equal installment and equal principal payments. Instantly calculate monthly payments and total interest.
Stamp Combination Calculator
Automatically calculate stamp combinations that match your desired amount. Supports 1-1000 yen stamps. Convenient tool for efficient post office purchases.
Pomodoro Timer
A timer that automatically cycles between 25-minute focus sessions and 5-minute breaks. Boost productivity for work and study with notifications and offline PWA support.
Timer & Stopwatch
Countdown timer and stopwatch in one tool. Features lap time recording and notifications. Perfect for cooking, exercise, and work time tracking.
Digital Seal Generator
Create digital seal images by entering your surname. Download in transparent PNG format. Perfect for remote work document approvals.
Address Normalizer
Auto-fill addresses from postal codes and standardize notation. Batch format full-width/half-width characters and prefecture names. Convenient for data cleansing.
JSON Formatter & Diff
JSON formatting and diff comparison in one tool. Essential for API development and debugging. Browser-based processing ensures confidential data security.
Dummy Data Generator
Generate large volumes of test data including Japanese names (kanji/kana), addresses, phone numbers, and emails. Perfect for development and testing sample data creation.
IP Address Checker
Check your global IP address instantly. Supports IPv4/IPv6. Useful for network configuration and troubleshooting.
Romaji Converter
Automatically convert hiragana and katakana to romaji (Hepburn/Kunrei systems). Convenient free tool for passport applications and international documents.
PDF Editor
PDF merge, split, reorder, rotate, add page numbers, and image-to-PDF conversion in one tool. Completely browser-based processing for security. Free.
Hash & Encryption
SHA-256/MD5 hash generation, AES encryption/decryption, and Base64 encoding executed in browser. Perfect for security development and testing.
Image Compressor
Compress images while maintaining high quality to reduce file size. Create mockups with smartphone and PC frames. Secure browser-based processing, completely free.
Image Cropper
Crop images with preset aspect ratios for passport photos, Instagram, X (Twitter), and more. Perfect for profile pictures and ID photos.
Business Email Generator
Auto-generate business emails for apologies, requests, and thanks with proper honorifics. Save time with templates. Easy creation.
EXIF Cleaner
View and remove metadata like location and date from photos. Essential for privacy protection before uploading to social media. Fully browser-based processing.
Speed Reading Tool
Read PDF/EPUB files at high speed with Japanese phrase-based parsing. Fully local processing for copyright protection. Adjustable 200-1000 WPM. Perfect for speed reading training.
Withholding Tax Calculator
[2025 Edition] Calculate withholding tax and net income from freelance fees. Supports two-tier tax rates over 1 million yen, consumption tax handling, and reverse calculation from net income.
Tools by Category
Find tools organized by purpose
💼 Business & Work
Invoice creation, tax calculation, loan simulation - tools to boost work efficiency
Tax Calculator
【2024年版】消費税10%・8%(軽減税率)を一括計算。内税・外税もワンクリックで変換できる無料シミュレーター。インボ...
Withholding Tax Calculator
【2025年版】フリーランスの報酬から源泉徴収税額と手取り額を自動計算。100万円超の二段階税率、消費税の内税・外税、手...
Loan Repayment Simulator
住宅ローンや自動車ローンの返済額を簡単シミュレーション。元利均等払い・元金均等払いの両方に対応。月々の返済額や総利息を瞬...
Digital Seal Generator
苗字を入力するだけで電子印鑑（デジタルハンコ）画像を無料作成。透過PNG形式でダウンロード可能。テレワークの書類承認に最...
Business Email Generator
謝罪・依頼・お礼などのビジネスメールを自動生成。正しい敬語で時間短縮。テンプレートから簡単作成。...
Stamp Combination Calculator
希望金額にピッタリ合う切手の組み合わせを自動計算。1円〜1000円の切手に対応。郵便局で無駄なく購入できる便利ツール。...
Address Label Maker
登録不要・無料で使える宛名ラベル作成ツール。住所を入力してA4用紙に印刷し、切って貼るだけで角2・長3封筒の宛名が完成し...
💻 Development & Web
QR code generation, color conversion, JSON formatting - streamline your development workflow
QR Code Generator
URLやテキストを入力するだけで、高品質なQRコードを即座に生成。画像ダウンロードも可能。イベント・名刺・チラシ作成に最...
Color Converter
HEX・RGB・HSLのカラーコードを相互変換。カラーピッカーで色を選ぶだけで全形式のコードを取得。Web制作・デザイン...
Password Generator
強力で安全なランダムパスワードを自動生成。長さ・文字種を自由に設定でき、複数個を一括生成可能。アカウント作成時の面倒な作...
URL Encoder/Decoder
日本語URLや特殊文字を含むURLを安全にエンコード・デコード。Web開発・API連携・リンク共有に必須の無料変換ツール...
JSON Formatter & Diff
JSON整形（フォーマット）と差分比較（Diff）を一つのツールで。API開発・デバッグに必須。ブラウザ内で完結し機密情...
Hash & Encryption
SHA-256/MD5ハッシュ生成、AES暗号化・復号化、Base64エンコードをブラウザ内で実行。セキュリティ開発・テ...
Markdown to HTML Converter
Markdownを即座にHTMLに変換。リアルタイムプレビュー付きで変換結果をすぐ確認。ブログ記事・技術文書作成に便利な...
Dummy Data Generator
テスト用の日本人氏名（漢字・フリガナ）、住所、電話番号、メールを大量生成。開発・検証用のサンプルデータ作成に最適。...
IP Address Checker
自分のグローバルIPアドレスを瞬時に確認。IPv4/IPv6対応。ネットワーク設定の確認やトラブルシューティングに。...
🖼️ Image & Design
Image compression, cropping, EXIF removal - essential tools before publishing images
📅 Date, Time & Age
Date calculation, Japanese era conversion, age calculator - essential for official documents
Date Calculator
「○日後はいつ？」「2つの日付の期間は？」を瞬時に計算。営業日計算・納期管理・プロジェクト進捗管理に便利な無料カレンダー...
Japanese Calendar Converter
西暦と和暦（令和・平成・昭和・大正・明治）を瞬時に相互変換。生年月日の確認や書類作成に便利な早見表付き無料ツール。...
Age Calculator
生まれ年から現在の年齢を瞬時に計算。西暦・和暦の両対応で、学年・干支も表示。履歴書作成や年齢確認に便利な無料ツール。...
Pomodoro Timer
25分集中+5分休憩を自動で繰り返すポモドーロ・テクニックタイマー。通知機能付きで、仕事・勉強の生産性が向上。オフライン...
Timer & Stopwatch
カウントダウンタイマーとストップウォッチの2機能を搭載。ラップタイム計測・通知機能付き。料理・運動・作業時間の計測に最適...
📝 Text Processing
Character counting, text formatting, seasonal words - streamline your writing workflow
Character Counter
【登録不要】リアルタイムで文字数・行数・原稿用紙枚数を自動計算。レポート・論文・ブログ記事の執筆に。改行・スペースを含む...
Online Notepad
ブラウザで使える無料メモ帳。自動保存機能付きで文字数カウント・ダウンロード・印刷にも対応。登録不要ですぐ使える、シンプル...
Text Formatter
改行変換(CRLF/LF)、スペース削除、全角半角変換を一括処理。プログラミング・データ整形・文字列クリーンアップに便利...
Seasonal Greetings & Kigo
手紙・年賀状・ビジネスメールの時候の挨拶を月別・旬別に検索。「拝啓」の後に続く季節の言葉が見つかる無料ツール。コピペです...
Romaji Converter
ひらがな・カタカナをローマ字（ヘボン式・訓令式）に自動変換。パスポート申請や海外向け書類作成に便利な無料ツール。...
📦 Other Utilities
Address normalization, PDF editing, speed reader - versatile tools for various needs