Free Online Calculators & Countdowns
Fast, accurate, and free calculators for finance, fitness, math, and everyday use. No registration required.
Financial Calculators
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Mortgage Calculator
Calculate your monthly mortgage payment, total interest paid, and full loan breakdown.
Loan Calculator
Calculate monthly payments, total interest, and total cost for any fixed-rate loan.
Auto Loan Calculator
Estimate your monthly car payment including taxes, trade-in value, and down payment.
Compound Interest Calculator
See how compound interest grows your money over time with optional monthly contributions.
Health & Fitness Calculators
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BMI Calculator
Calculate your Body Mass Index (BMI) and see your weight category.
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
Calorie Calculator
Estimate how many calories you need per day based on your goal — lose, maintain, or gain weight.
Body Fat Calculator
Estimate body fat percentage using the U.S. Navy circumference method.
Math Calculators
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Scientific Calculator
Full-featured scientific calculator with trig, logarithms, powers, and more.
Fraction Calculator
Add, subtract, multiply, and divide fractions with automatic simplification.
Percentage Calculator
Solve all types of percentage problems — find %, what % of X is Y, and percentage change.
Triangle Calculator
Solve any triangle from sides and angles — SSS, SAS, ASA, AAS configurations.
Conversions Calculators
See all →Construction & Home Calculators
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Concrete Calculator
Calculate how much concrete you need for slabs and columns, in cubic yards, feet, and meters.
Paint Calculator
Calculate how many gallons of paint you need for any room or surface.
Flooring Calculator
Calculate how much flooring material you need for any room in square feet and boxes.
Roofing Calculator
Calculate roofing material needed in squares (100 sq ft) for any roof pitch.
Everyday Calculators
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Age Calculator
Calculate exact age in years, months, days, hours, and find out when the next birthday is.
Date Difference Calculator
Calculate the number of days, weeks, months, and years between two dates.
Time Calculator
Add or subtract multiple time values in hours, minutes, and seconds.
GPA Calculator
Calculate your GPA from course grades and credit hours.
Science Calculators
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Subnet Calculator
Calculate network address, broadcast address, host range, and more from an IP and subnet mask.
Binary/Hex/Octal Converter
Convert numbers between binary, hexadecimal, octal, and decimal bases.
Exponent Calculator
Calculate any base raised to any power, including negative and fractional exponents.
Logarithm Calculator
Calculate logarithms in any base, including natural log and log base 10.
More Calculators
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Random Number Generator
Generate random integers or decimals in any range, with or without duplicates.
Password Generator
Generate strong, secure random passwords with custom length and character sets.
Aspect Ratio Calculator
Calculate aspect ratio from dimensions and scale images/videos while maintaining ratio.
Roman Numeral Converter
Convert between Roman numerals and standard Arabic numbers.