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Finance
8 calculatorsCompound Interest Calculator
See how your money grows over time.
Simple Interest Calculator
Linear interest on an initial amount.
Tip & Bill Split Calculator
Split the bill with friends and add a tip of 15%, 18% or 20%.
Loan & Installments Calculator
Monthly installment, total paid and total interest.
ROI Calculator
Return on investment as %, profit and multiple.
Markup & Margin Calculator
From cost to sale price with actual margin.
Discount Calculator
Final price after one, two or three successive discounts.
Rule of 72
How many years for your money to double.
Health
5 calculatorsBMI Calculator
Body Mass Index with WHO classification.
Daily Calorie Calculator (TDEE)
How many calories you burn each day based on sex, age and activity.
Running Pace Calculator
Pace, speed and times for 5k, 10k, half and full marathon.
Ideal Weight Calculator
Ideal body weight by Devine, Robinson, Miller and Hamwi formulas.
Hydration Calculator
How many liters of water to drink per day.
Math
2 calculatorsDate & Time
3 calculatorsConversions
13 calculatorsLength Converter
Meters, feet, inches, miles — all in one place.
Weight Converter
Convert kg, pounds, ounces and tons instantly.
Volume Converter
Liters, gallons, cups and milliliters.
Temperature Converter
Celsius, Fahrenheit and Kelvin — instant conversion.
Area Converter
m², hectares, acres, sq ft — for land and construction.
Speed Converter
km/h, mph, m/s and knots — quick conversion.
Energy Converter
Joules, calories, kWh and BTU in instant conversion.
Pressure Converter
Pascal, bar, psi, atm and mmHg — quick conversion.
Digital Data Converter
Bits, bytes, KB, MB, GB, TB — decimal and binary.
Time Converter
Seconds, minutes, hours, days, weeks and years.
Angle Converter
Degrees, radians and gradians — for trig and CAD.
Force Converter
Newton, kgf, lbf and dyne — engineering conversion.
Power Converter
Watt, kW, HP and CV — motor and electrical conversion.
Daily life
2 calculatorsScience
1 calculatorsArticles & Guides
Long-form guides — not just numbers, real understanding.
How compound interest works: a complete guide with examples
Understand what Einstein called the eighth wonder of the world. Formula, worked examples, comparison with simple interest, and practical strategies for investors.
Gross vs net salary: how to compare job offers across countries
How to translate gross to net across the US, UK, Brazil, and Spain. Tax tables, social security and the hidden differences that matter when negotiating offers.
BMI vs body fat percentage: which one should you actually use?
BMI is simple but has well-known limitations. See when it fails, how body fat percentage complements it, and which measurement methods are worth your time.
Fixed rate vs variable rate mortgage: how to decide and run the numbers
How to actually evaluate fixed vs variable mortgages with concrete numbers. Sensitivity analysis, break-even rates, and rules of thumb that survive contact with reality.
⚠️ Important notice
The calculators and articles on calculadora.work are for educational and informational purposes only. We are not accountants, lawyers, doctors, or financial advisors. Results are estimates based on public formulas and may contain inaccuracies. For important decisions — tax filings, contracts, medical diagnoses, financial planning — always consult a qualified professional. We are not liable for decisions made based on this site's content.
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A single home for the calculators people use every day — personal finance, health, studies and curiosities. Every tool runs offline in your browser: nothing is sent to servers, all math happens on your device in real time.
The focus is simple: quick input, clear output, and a plain-English explanation below for anyone who wants to understand the formula. Mobile-optimized and available in Portuguese, English and Spanish.