简单好用的免费工具
以下所有工具都完全在你的浏览器中运行——无需账号、无需上传、不做追踪。选择一个分类即可开始。
🕐 时间与日期
Age Calculator
Free age calculator. Enter your date of birth to see your exact age in years, months and days, your total days lived, and a countdown to your next birthday.
Countdown Timer
Free countdown timer. Enter any future date and see exactly how many days, hours, minutes and seconds remain. Works in your browser, no signup needed.
Day of the Week
Free day of week calculator. Find out what day of the week any date falls on. Check birthdays, historical dates, or any future date instantly.
Days Between Dates
Free days between dates calculator. Find exactly how many days, weeks, and months are between any two dates. Works instantly in your browser.
Leap Year Calculator
Free leap year calculator. Check if any year is a leap year and find the next leap year. Instant results in your browser.
Pomodoro Timer
Free Pomodoro timer. 25-minute focus sessions with 5-minute short breaks and 15-minute long breaks. No signup needed. Runs in your browser with sound alerts.
Stopwatch
Free online stopwatch with millisecond precision. Start, pause, record lap times, and reset. No download needed. Works entirely in your browser.
Time Calculator
Free time calculator. Add or subtract hours, minutes, and seconds easily. Great for calculating total work hours, travel times, and durations.
Time Zone Difference Calculator
Free time zone difference calculator. Find the exact hour difference between any two cities or time zones worldwide. Instant results in your browser.
🔢 数学
Area Calculator
Free area calculator. Calculate the area of rectangles, circles, triangles, squares, and trapezoids. Enter dimensions and get the area instantly in your browser.
Aspect Ratio Calculator
Free aspect ratio calculator. Enter width and height to get the simplified ratio (e.g. 1920×1080 = 16:9) and scale to any new size instantly.
Online Basic Calculator
Free online calculator. Perform addition, subtraction, multiplication, and division. A clean, simple, full-featured basic calculator that works entirely in your browser.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal instantly. Free online base converter with instant results.
Fraction Calculator
Free fraction calculator. Add, subtract, multiply or divide any two fractions and get the simplified result instantly. Also shows the decimal equivalent.
GCD Calculator
Free GCD calculator. Find the Greatest Common Divisor (GCD/GCF/HCF) of any set of numbers. Also shows the LCM. Instant results in your browser.
LCM Calculator
Free LCM calculator. Find the Least Common Multiple (LCM) of any set of numbers. Also shows the GCD. Instant results in your browser.
Octal Number Converter
Free octal converter tool. Instantly convert any number between base 2 (binary), base 8 (octal), base 10 (decimal), and base 16 (hex).
百分比计算器
免费百分比计算器。求一个数的百分之几、一个数是另一个数的百分之几，并即时计算百分比的增加或减少。
Prime Number Checker
Free prime number checker. Enter any positive integer to instantly find out if it is prime. Also shows all divisors and the prime factorization.
Pythagorean Theorem Calculator
Free Pythagorean theorem calculator. Enter any two sides of a right triangle to find the third. Works for hypotenuse or either leg. Instant and accurate.
Roman Numeral Converter
Free Roman numeral converter. Convert any number from 1 to 3999 to Roman numerals, or convert Roman numerals back to decimal. Instant and accurate.
Rounding Calculator
Free rounding calculator. Round any number to a chosen number of decimal places, or round up or down, instantly and precisely in your browser.
Square Root Calculator
Free square root calculator. Find the square root of any positive number instantly. Also shows the square (n²). Works in your browser with no signup required.
💰 财务
50/30/20 Budget Rule Calculator
Free 50/30/20 budget rule calculator. Enter your monthly income to instantly see how much to allocate to needs, wants, and savings.
Compound Interest Calculator
Free compound interest calculator. Enter a principal, interest rate, and time period to see how compound interest grows your investment. Monthly, quarterly, or annual compounding.
Currency Converter
Free currency converter with approximate exchange rates. Convert USD, EUR, GBP, JPY, BRL, and 30+ more currencies instantly in your browser.
Discount Calculator
Free discount calculator. Enter the original price and the discount percentage to instantly see the final sale price and exactly how much you save.
Loan Calculator
Free loan calculator. Enter the loan amount, interest rate, and term to see your monthly payment and total interest paid. Works for mortgages, car loans, and personal loans.
Retirement Savings Calculator
Free retirement calculator. Estimate your retirement savings based on monthly contributions, expected return, and years to retirement.
Sales Tax Calculator
Free sales tax calculator. Enter a price and a tax rate to add tax to a net price or extract it from a gross price. Works for VAT, GST, and any percentage.
🎲 随机抽取
Coin Flip
Free online coin flip. Tap to flip a fair virtual coin and get heads or tails instantly, with a running tally. Works in your browser, no app needed.
Random Letter Generator
Free random letter generator. Pick one or many random letters from A to Z, in uppercase, lowercase or mixed case, instantly and fairly in your browser.
Random Name Generator
Free random name generator. Generate random first and last names by gender and cultural origin. Perfect for writers, game developers, and baby name inspiration.
Random Number Generator
Free random number generator. Pick one or many random numbers between any minimum and maximum, with an option for unique results. Secure and instant in your browser.
Dice Roller
Free online dice roller. Roll d4, d6, d8, d10, d12, d20, and d100 dice, alone or in groups. Perfect for D&D, tabletop RPGs, and board games. No download needed.
🎮 游戏与娱乐
📝 文本与文字
List Alphabetizer
Free online list alphabetizer. Sort any list A-Z, Z-A, by last word, or remove duplicates instantly. Paste your list and click sort.
Backwards Text Generator
Free backwards text generator. Instantly reverse the letters, the word order or the line order of any text in your browser, then copy the result.
Binary Translator
Free binary translator. Convert any text to binary code and decode binary back to text, with full Unicode support, instantly and privately in your browser.
Case Converter
Free online case converter. Instantly change text to UPPERCASE, lowercase, Title Case, Sentence case, aLtErNaTiNg case and small caps in your browser.
Character Counter
Free character counter. Count characters (with and without spaces), words, sentences, paragraphs, and lines in any text. Instant, no signup needed.
Lorem Ipsum Generator
Free Lorem Ipsum generator. Create placeholder dummy text by paragraphs, sentences or words for design mockups and layouts, then copy it in one click.
Morse Code Translator
Free Morse code translator. Convert any text to Morse code dots and dashes, or decode Morse code back to text. Includes audio playback. Works entirely in your browser.
Palindrome Checker
Free palindrome checker. Instantly test whether a word, phrase or number reads the same forwards and backwards, ignoring case, spaces and punctuation.
Reading Time Calculator
Free reading time calculator. Paste any text to instantly see the word count, estimated reading time, and estimated speaking time. No signup needed.
Syllable Counter
Free syllable counter. Count the number of syllables in any English word or text instantly. Useful for poetry, song lyrics, and haiku writing.
Text Diff Tool
Free text diff tool. Compare two texts and highlight the differences between them. Find added, removed, and changed words instantly.
Text Repeater
Free text repeater. Repeat a word, phrase or line as many times as you like, with a line break, space or comma between copies, then copy the result instantly.
字数统计
免费实时字数统计。粘贴或输入文本，即可在浏览器中立即统计字数、字符数、句子数、段落数和预计阅读时间。
📱 社交媒体
QR Code Generator
Free QR code generator. Create a QR code for any URL, text, WiFi password, or contact information. Download as PNG. Works entirely in your browser.
TikTok Caption Analyzer
Free TikTok caption analyzer. See character count vs 2200 limit, hashtag count, word count, and estimated read time. Optimize your TikTok captions instantly.
❤️ 健康与身体
Blood Type Compatibility Checker
Free blood type compatibility checker. Select your ABO/Rh blood type to instantly see who you can donate blood to and who you can receive blood from.
BMI 计算器
免费 BMI 计算器。以公制或英制单位输入你的身高和体重，即可在浏览器中立即得到身体质量指数及其分类。
BMR Calculator
Free BMR calculator. Calculate your Basal Metabolic Rate — the calories your body burns at rest per day. Uses the Mifflin-St Jeor equation.
Food Calorie Calculator
Free calorie calculator. Look up approximate calories per 100g for common foods. Great for diet tracking and meal planning.
Ideal Weight Calculator
Free ideal weight calculator. Find the healthy weight range for your height and sex using the BMI method and the Robinson, Miller, and Devine formulas.
🏠 家居与汽车
Electricity Cost Calculator
Free electricity cost calculator. Enter an appliance wattage, hours of use per day, and your electricity rate to see daily, monthly, and annual running costs.
Paint Calculator
Free paint calculator. Enter your wall dimensions, number of coats, and paint coverage to calculate exactly how many litres of paint you need.
🔧 实用工具
Color Picker
Free color picker. Select any color and instantly get its HEX, RGB, and HSL codes. Copy with one click. Works entirely in your browser.
CSS Gradient Generator
Free CSS gradient generator. Create linear and radial gradients with any colors and instantly get the CSS code. No signup needed.
Random Color Generator
Free random color generator. Generate a random colour and see its HEX, RGB and HSL codes instantly. Great for design inspiration and picking palettes.