Tools
Developer utilities & practical tools. No signup, no tracking — everything runs in your browser.
Developer Tools
- JSON FormatterFormat, validate, and minify JSON data.
- Base64 Encoder / DecoderEncode and decode Base64 strings with full UTF-8 support.
- URL Encoder / DecoderPercent-encode and decode URLs with encodeURIComponent or encodeURI.
- UUID GeneratorGenerate random UUID v4 values with the Web Crypto API.
- Hash GeneratorCompute SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text.
- Regex TesterTest and debug regular expressions with live match highlighting.
- Unix Timestamp ConverterConvert between Unix timestamps and human-readable dates.
- Color ConverterConvert colors between HEX, RGB, and HSL with a live preview.
- JWT DecoderDecode and inspect JSON Web Tokens in your browser.
- Diff ViewerCompare two texts line by line.
- HTML EntitiesEncode and decode HTML entities.
- Lorem IpsumGenerate placeholder text by paragraphs, sentences, or words.
- Number BaseConvert between binary, octal, decimal, and hex.
- Text CounterCount characters, words, sentences, and analyze text frequency in real time.
- Markdown PreviewRender Markdown to HTML live as you type.
- QR Code GeneratorTurn any text or URL into a QR code and download it as PNG or SVG.
- Excel Diff ViewerCompare two Excel workbooks (.xlsx, .csv) cell-by-cell and row-by-row.
Calculators
- Percentage CalculatorWork out any percentage — of a number, as a ratio, or as a change.
- Age CalculatorFind your exact age in years, months, and days from your birth date.
- Unit ConverterConvert length, weight, temperature, volume, area, speed, and data.
- Date Difference CalculatorCount the days, weeks, and months between two dates.
- BMI CalculatorCheck your Body Mass Index and weight category in metric or imperial.
- Compound Interest CalculatorSee how savings grow with compound interest and regular contributions.
- Loan Payment CalculatorEstimate the monthly payment, total cost, and interest on a loan.
Life in Japan
- Payslip DecoderUnderstand each line of a Japanese payslip and your take-home pay.
- Tax SimulatorEstimate Japanese income tax, resident tax, and take-home pay.
- Visa Renewal TimelineSee when to renew your residence status and what documents you need.
- Moving ChecklistTrack every procedure for moving house in Japan on a timeline.
- Korean ⇄ English TypingRecover text typed in the wrong keyboard mode.