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Science-backed health, fertility, finance and math calculators with transparent formulas, peer-reviewed references and instant results — free, private, no signup.
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Money & Finance
Mortgage, loans, investing, tax
40 free calculators
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Health
BMI, calories, pregnancy, heart
19 free calculators
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Fitness
Pace, power, strength, TDEE
8 free calculators
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Education & Math
Percentages, statistics, algebra, GPA
21 free calculators
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Home Improvement
Paint, tile, flooring, energy
6 free calculators
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Construction
Concrete, brick, gravel, asphalt
5 free calculators
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Automotive
Fuel cost, economy, tire size
3 free calculators
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Technology
Download time, subnets, binary
6 free calculators
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Engineering
Ohm's law, voltage drop, torque
6 free calculators
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Cooking & Baking
Cups to grams, dough, coffee
5 free calculators
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Everyday Tools
Age, dates, time zones, tips
9 free calculators
Popular calculators
🏠Mortgage CalculatorCalculate your monthly mortgage payment, total interest paid and loan amount using standard amortization. Includes the 28/36 affordability rule.⚖️BMI CalculatorCalculate your Body Mass Index instantly with WHO classification and NHS ethnicity-adjusted thresholds. Metric & imperial, healthy weight range included.💳Loan CalculatorCalculate the monthly payment, total paid, and total interest for any amortizing loan. Enter amount, annual rate, and term in months.🎂Age CalculatorCalculate your exact age in years, months and days from your date of birth, plus total days, weeks, months lived and days until your next birthday.％Percentage CalculatorCalculate percentages three ways: find a percent of a number, find what percent one number is of another, or calculate percent change between two values.📈Compound Interest CalculatorCalculate compound interest with A = P(1+r/n)^nt. Choose annual, quarterly, monthly or daily compounding. Includes Rule of 72 doubling-time estimate.🍎Calorie CalculatorCalculate daily calories to maintain, lose or gain weight using the Mifflin-St Jeor equation, activity multipliers and safe minimum-calorie floors.🎓GPA CalculatorCalculate your GPA on the 4.0 scale with credit weighting: quality points, total credits and a letter-grade conversion table for the common US convention.🌴Retirement CalculatorEstimate your retirement nest egg using compound growth and the Bengen 4% safe-withdrawal rule. See projected monthly income in today's dollars.🤰Pregnancy Due Date CalculatorEstimate your pregnancy due date from your last menstrual period, conception date, or IVF transfer using ACOG Naegele's Rule and ASRM conventions. Free tool.🏛️Tax CalculatorEstimate income tax using US 2025 federal brackets or UK 2025-26 bands. See tax due, after-tax income, and effective rate. Educational reference only.⚡TDEE CalculatorCalculate your Total Daily Energy Expenditure with the Mifflin-St Jeor equation and standard activity multipliers. Maintenance, loss and gain estimates.
All calculators
Money & Finance
- 🌴 Retirement Calculator
- 🏠 Mortgage Calculator
- 💎 Net Worth Calculator
- 🧾 Simple Interest Calculator
- 📈 Compound Interest Calculator
- 💰 Credit Card Payoff Calculator
- 📊 IRR Calculator
- 💵 Paycheck Calculator
- 🏛️ Tax Calculator
- 🎈 Inflation Calculator
- 💳 Loan Calculator
- 🚙 Car Loan Calculator
- 📉 Amortization Calculator
- ⛓️ Debt Payoff Calculator
- 🔑 Mortgage Affordability Calculator
- 🔄 Refinance Calculator
- 🤝 Personal Loan Calculator
- 🗓️ EMI Calculator
- 🐖 Savings Calculator
- 🌱 Investment Calculator
- 🎯 ROI Calculator
- ⏩ Future Value Calculator
- ⏪ Present Value Calculator
- 📐 CAGR Calculator
- 💸 Dividend Calculator
- 🔥 FIRE Calculator
- 🏦 Capital Gains Tax Calculator
- 🧾 VAT Calculator
- 🧮 GST Calculator
- 💼 Salary Calculator
- 🏪 Profit Margin Calculator
- 🏷️ Markup Calculator
- 🏠 USA Mortgage Calculator
- 🏠 UK Mortgage Calculator
- 🏠 South Africa Bond Calculator
- 🏠 Australia Mortgage Calculator
- 🏠 Canada Mortgage Calculator
- 🏠 India Home Loan Calculator
- 🏠 Germany Mortgage Calculator
- 🏠 China Mortgage Calculator
Health
- ⚖️ BMI Calculator
- 📏 Waist-to-Hip Ratio Calculator
- 🔵 Body Roundness Index Calculator
- ❤️ Max Heart Rate Calculator
- 💓 Target Heart Rate Calculator
- 🧍 Body Fat Calculator
- 🔥 BMR Calculator
- 🍽️ Macro Calculator
- 🎯 Ideal Weight Calculator
- 💪 Lean Body Mass Calculator
- 💧 Water Intake Calculator
- 🥚 Protein Calculator
- 🍼 Gestational Age Calculator
- 😴 Sleep Calculator
- 🍎 Calorie Calculator
- 🤰 Pregnancy Due Date Calculator
- 🌸 Ovulation Calculator
- 📅 Fertility Window Calculator
- 👶 Conception Date Calculator
Fitness
Education & Math
- ％ Percentage Calculator
- 📈 Percentage Increase Calculator
- 📉 Percentage Decrease Calculator
- ½ Fraction Calculator
- 🔢 Decimal to Fraction Calculator
- ⚖️ Ratio Calculator
- ➗ Average Calculator
- μ Mean Calculator
- 𝑀 Median Calculator
- σ Standard Deviation Calculator
- 🎲 Probability Calculator
- 🧪 Sample Size Calculator
- 📏 Confidence Interval Calculator
- 𝑍 Z-Score Calculator
- 𝑥² Quadratic Equation Calculator
- ㏒ Log Calculator
- 🔺 Exponent Calculator
- 🔟 Prime Number Calculator
- 🎓 GPA Calculator
- 🧮 Scientific Calculator
- ▦ Matrix Calculator