Popular Tools

Accurately calculate radian values for inverse trig functions like arcsin and arccos. Supports 6 function types and custom decimal precision.

Calculate the Compound Annual Growth Rate (CAGR) of your investments. Enter the initial value, final value, and number of years to get an accurate annualized return assessment.

Generate single or bulk email-format test data with RFC-reserved example domains, or add domains you own or are authorized to test.

Enter your birth date to instantly calculate your exact age, traditional Chinese age, and total days alive, plus find your Chinese zodiac, horoscope, and lunar birthday.

Convert Chinese characters (Hanzi) to Pinyin with tone marks or numbers. Features smart polyphone recognition and a dedicated name mode.

Generate a formatted random phone number by country, region, carrier, or prefix for software testing, demos, and sample data.

Quickly test headphone connection and left/right audio channels to troubleshoot device issues. Supports both wired and Bluetooth headphones.

Bulk generate random Chinese names by gender, length, and surname for novels, games, and character design.

Generate random decimals with a specified range, decimal places, and quantity. Ideal for data analysis, simulation experiments, and more.

Estimate creatinine clearance (CrCl) with the Cockcroft–Gault equation using age, weight, sex, and serum creatinine.

Enter your baby's birth date to instantly view the Gregorian and Lunar dates, as well as the day of the week, for their one-month, 100-day, and first birthday milestones. Perfect for planning your celebrations.

Free online two-way converter for Gregorian dates and Bazi (Four Pillars of Destiny). Supports Ziwei and Ziping school Rat hour (Zi hour) rules for accurate Chinese astrology calculations and calendar conversions.

Measure environmental noise decibel levels in real-time using your device's microphone. Evaluate noise levels at home, in the office, or in public spaces to protect your hearing.

A bidirectional PX to REM converter for front-end developers and designers, featuring customizable root font sizes.

Quickly calculate VAT-inclusive prices, VAT-exclusive prices, and tax amounts with this free online VAT calculator. Supports custom tax rates.