Free Online Calculator Collection

Over 70 free online calculators for everyday use. No registration required.

💰 Finance Calculators

Tip Calculator - Calculate tips and split bills
Percentage Calculator - Calculate percentages and rate of change

🏃 Health & Fitness

BMI Calculator - Body Mass Index, obesity measurement
Calorie Calculator - Daily calorie needs (TDEE), BMR

📅 Date & Time Calculators

Lunar Calendar - Solar↔Lunar date conversion
Date Calculator - Days between two dates
Time Calculator - Add/subtract time, work hours
D-Day Calculator - Countdown to important dates
Age Calculator - Calculate age from birthdate
Day of Week - Find day of week for any date
World Clock - Current time in major cities
Time Difference - Time zone differences
Korean SAT D-Day - Suneung countdown
Black Friday Dates - Black Friday by year
Pomodoro Timer - 25-minute focus timer
Stopwatch & Timer - Precision timing

🔢 Math & Numbers

Decimal Rounding - Round, ceil, floor numbers
Unit Converter - Length, weight, temperature, volume
Statistics Calculator - Mean, variance, standard deviation
Number to Words - Convert numbers to words
Page Count - Character to page conversion

🛠️ Developer Tools

Barcode/QR Generator - Create barcodes and QR codes
CSV↔JSON Converter - Convert between CSV and JSON
Base64/URL Encoder - Encoding/decoding tools
Regex Tester - Test regular expressions
URL Parser - Parse URLs, extract parameters
Time Format Converter - Unix timestamp, ISO 8601
Text Diff - Compare two texts
Text Analyzer - Count characters, words, paragraphs
Text Formatter - Case conversion, sort, dedupe

Popular Lunar Dates

Free to Use

All calculators are free with no registration required. Available in Korean and English.