Free Online Calculators
Simple, fast and accurate calculators for everyday use. No sign-up, no downloads — just answers.
5 calculators across 5 categories. Browse all
Popular Calculators
View allAge Calculator
Find your exact age in years, months, days, hours and minutes.
OthersBMI Calculator
Calculate your Body Mass Index from your height and weight.
Fitness & HealthEMI Calculator
Work out the monthly payment on any loan, plus total interest.
FinancialLength Converter
Convert between metres, feet, inches, miles, kilometres and more.
ConversionsPercentage Calculator
Solve any percentage problem, including increase and decrease.
Maths
Explore Calculators
Pick a category to see every calculator it contains.
Fitness & Health
1 calculator
BMI, calories, body fat and everyday health metrics.
ExploreFinancial
1 calculator
Loans, EMI, interest, savings and investment planning.
ExploreMaths
1 calculator
Percentages, fractions, averages, ratios and more.
ExploreConversions
1 calculator
Length, weight, temperature, area, speed and data units.
ExploreOthers
1 calculator
Age, dates, tips, passwords and other handy tools.
Explore
Free Online Calculators & Tools
Use CalcNinja to quickly work out fitness metrics, financial estimates, mathematical values, unit conversions and everyday calculations. Every tool runs in your browser, gives an answer the moment you press calculate, and explains the formula behind it so you can check the result.
Nothing you type is stored or sent anywhere, there is no account to create, and every calculator is free to use on mobile, tablet and desktop.