Popular Tools

Fetal Weight Calculator

Quickly estimate fetal weight using ultrasound data like Biparietal Diameter (BPD), Abdominal Circumference (AC), and Femur Length (FL). Uses the Hadlock formula to provide a reliable reference for pregnancy assessment.

BMR Calculator (Basal Metabolic Rate)

Calculate the minimum daily calories your body needs at rest based on gender, height, weight, and age. Get a scientific reference for your diet and fitness plans.

PX to PT Converter

A pixel (PX) to point (PT) unit conversion tool for designers and developers. Supports custom PPI for typography and layout adaptation.

Martian Text Converter

Convert between Simplified Chinese, Traditional Chinese, and Martian text (Huoxingwen) for personalized online communication and unique nicknames.

Body Fat Calculator

Calculate your body fat percentage using BMI and waist circumference formulas. Get instant body composition insights for fitness and health management.

Random Color Generator

Provides controllable random color generation for designers and developers, supporting multiple formats and hue filtering.

Trigonometry Calculator

Calculate six trigonometric functions from radian values with custom decimal precision.

Random Email Batch Generator

Generate correctly formatted random email addresses in bulk, with customizable domains and prefix rules — ideal for testing sign-ups and protecting privacy.

Random User Agent Generator

Generate random browser User-Agent strings for developers, QA testers, and web scrapers to simulate various devices and platforms.

First Seven Mourning Date Calculator

Accurately calculate traditional memorial dates including the First Seven, Third Seven, Fifth Seven, and Seventh Seven. Supports both Lunar and Gregorian calendar inputs to help families follow traditional mourning customs.

FVIFA Calculator

Calculate the Future Value Interest Factor of an Annuity (FVIFA) instantly. Enter your interest rate and periods to estimate the future value of regular investments with this free online calculator.

BMI Calculator

Calculate your Body Mass Index (BMI) and assess your health status based on height and weight. Ideal for personal health monitoring.

IPv4 / IPv6 Address Converter

A two-way IPv4 and IPv6 address converter for network configuration, debugging, and format validation.

Caesar Cipher Encoder & Decoder

Free online Caesar cipher encryption and decryption tool. Supports custom alphabets and shift offsets. Ideal for cryptography learning and fun.

Prime and Composite Number Calculator

Instantly identify prime, composite, or special numbers. Supports batch checking and mathematical property analysis.

Bra Size Calculator

Accurately calculate your cup and bra size using your bust and underbust measurements to find the perfect fitting bra.

Body Surface Area (BSA) Calculator

Calculate Body Surface Area (BSA) based on height and weight using multiple medical formulas. Ideal for medication dosage estimation and physiological research.

Countdown Calculator

Calculate the exact countdown to any future date. Supports both Gregorian and Lunar calendars, displaying the remaining weeks, days, hours, minutes, and seconds.

Random Number Generator

Generate random integers or decimals within a specified range, featuring duplicate removal, sorting, and formatted output.

Circle Area Calculator

Quickly calculate the area of a circle by entering the radius, diameter, or circumference. Supports custom units and precision settings.