Online Calculators Directory
Welcome to our comprehensive directory of 100+ free online calculators, organized by category for quick and easy access. Whether you need math calculations, financial planning, health assessments, time conversions, or specialized tools, you'll find the right calculator here.
All our calculators are:
- 100% Free - No registration or subscriptions required
- Mobile-Friendly - Works on all devices (desktop, tablet, smartphone)
- Instant Results - Get accurate calculations immediately
- Step-by-Step Solutions - Many calculators show detailed explanations
Math & Numbers Calculators
55 calculators for percentage, fractions, basic math, advanced math, number theory, number formats, and geometry.
Popular Math Calculators:
- Percentage Calculator - Calculate percentages, percentage changes, and more
- Fraction Calculator - Add, subtract, multiply, and divide fractions
- Greatest Common Factor (GCF) - Find the GCF of numbers
- Least Common Multiple (LCM) - Calculate the LCM of numbers
- Prime Numbers Checker - Check if a number is prime
Categories: Percentage (9) • Fractions (10) • Basic Math (11) • Advanced Math (5) • Number Theory (8) • Number Formats (8) • Geometry (4)
Finance & Business Calculators
7 calculators for compound interest, currency conversion, discounts, taxes, tips, and stock recovery.
- Compound Interest Calculator - Calculate investment growth over time
- Currency Converter - Convert between different currencies
- Discount Calculator - Calculate discounts and final prices
- Percentage Recovery Calculator - Gain needed after a stock loss
- Sales Tax Calculator - Calculate sales tax and total cost
- Stock Loss Recovery Calculator - How much gain to break even
- Tip Calculator - Calculate tips and split bills
Health & Fitness Calculators
9 calculators for BMI, calories burned, ideal weight, life expectancy, and pregnancy.
- BMI Calculator (Metric) - Calculate Body Mass Index using kg and cm
- BMI Calculator (Imperial) - Calculate BMI using pounds and inches
- BMI Calculator (UK) - Calculate BMI using stones and feet/inches
- Calories Burned Calculator - Estimate calories burned during activities
- Ideal Body Weight - Calculate your ideal weight
- Life Expectancy Calculator - Estimate life expectancy (US)
- Ovulation / Pregnancy Calculator - Track ovulation and pregnancy
- Running Calorie Calculator - Calories burned while running
- Walking Calorie Calculator - Calories burned while walking
Time & Date Calculators
11 calculators for time conversion, age calculation, day of week, leap year, and date calculations.
- Time Units Converter - Convert between time units
- Age Calculator - Calculate your exact age
- Day of the Week Calculator - Find day of week for any date
- Days From Today - Find a future date from today
- Days Until - Countdown to any date
- Easter Sunday Calculator - Find Easter date for any year
- Time to Decimal - Convert time to decimal hours
- Time to Fraction - Convert time to fractions
- Leap Year Calculator - Check if any year is a leap year
- Military Time Converter - Convert 24-hour clock to AM/PM
- Weeks to Months - Convert weeks to months
Computer & Electronics Calculators
6 calculators for base conversion, data storage, power conversion, and electronics.
- Base Converter - Convert between binary, octal, decimal, and hexadecimal
- Data Storage Converter - Convert bits, bytes, KB, MB, GB, TB
- dBm / dBW to mW / W - Decibel power conversion
- mW / W to dBm / dBW - Reverse power conversion
- Volts, Amps, Watts & Ohms Calculator - Ohm's law calculations
- Volts, Amps & Watts Calculator - Power calculations
Text & Language Tools
4 tools for text analysis and number-to-text conversion.
- Number to Words - Convert numbers to written words
- Words to Number - Convert written words to numbers
- Word & Character Counter - Count words, characters, and paragraphs
- Spanish Numbers - Learn Spanish number names
Chemistry Calculators
8 calculators for chemical equations, pH, molarity, dilution, molar mass, and stoichiometry.
Browse All Chemistry Calculators →
- Chemical Equation Balancer - Balance any chemical equation instantly
- pH Calculator - Calculate pH of acids, bases, and buffers
- Molar Mass Calculator - Find molecular weight of any compound
- Molarity Calculator - Calculate molar concentration
- Dilution Calculator (M1V1 = M2V2) - Solution dilution calculations
- Empirical Formula Calculator - Determine empirical formula from percentages
- Grams to Moles - Convert mass to moles
- Moles to Grams - Convert moles to mass
Cooking Measurement Converters
US customary volume converters for cooking and baking — cups, tablespoons, ounces, quarts, and gallons with exact NIST ratios.
Browse Cooking Measurement Guide →
Popular Cooking Conversions:
- Cups to Fluid Ounces - 1 cup = 8 fl oz
- Cups to Tablespoons - 1 cup = 16 tbsp
- Gallons to Fluid Ounces - 1 gal = 128 fl oz
- Quarts to Cups - 1 qt = 4 cups
- Weight to Volume for Recipes - Ingredient-aware (80+ ingredients)
Fun & Lifestyle Calculators
3 calculators for pet age and zodiac signs.
- Cat Age Calculator - Convert cat age to human years
- Horse Age Calculator - Convert horse age to human years
- Zodiac Sign Finder - Find your zodiac sign
Also Available: Unit Converters
In addition to calculators, we also offer 50+ unit converters for length, weight, temperature, volume, and more.
About Our Calculator Directory
CoolConversion's calculator directory provides free access to over 100 specialized calculation tools, organized by category for easy navigation. Whether you're a student, teacher, professional, or just need quick calculations, our tools are designed for accuracy and ease of use.
Why Choose Our Calculators?
- Always Free: No payment, registration, or subscription required
- Mobile-Optimized: Responsive design works perfectly on all screen sizes
- Educational: Many calculators include step-by-step explanations
- No Installation: Works instantly in any modern web browser
- Privacy-Focused: No data collection, all calculations done locally
- Regularly Updated: New calculators added and existing ones improved
Popular Calculator Categories
Our most popular category is Math & Numbers with 55 calculators covering everything from basic percentage calculations to advanced number theory. The Chemistry category includes equation balancing, pH, molarity, and molar mass tools. The Health & Fitness category features BMI calculators for different measurement systems and various calorie burn estimators.
For financial planning, our Finance & Business calculators help with compound interest, currency conversion, and tax calculations. Students particularly love our fraction and percentage calculators that show complete step-by-step solutions.