Patrache Calc
90 Free Online Calculators
Health, Finance, Math, Date & Time, Unit Conversion, Science, Digital, and Daily Life — all the calculators you need in one place.
- BMI CalculatorHealth
- Calorie CalculatorHealth
- BMR CalculatorHealth
- Body Fat CalculatorHealth
- Ideal Weight CalculatorHealth
- Pregnancy Due Date CalculatorHealth
- Sleep CalculatorHealth
- Water Intake CalculatorHealth
- Macro CalculatorHealth
- Heart Rate Zone CalculatorHealth
- Pregnancy Weight Gain CalculatorHealth
- Pace CalculatorHealth
- Waist-Hip Ratio CalculatorHealth
- One Rep Max CalculatorHealth
- Ovulation CalculatorHealth
- Compound Interest CalculatorFinance
- Loan CalculatorFinance
- Tip CalculatorFinance
- ROI CalculatorFinance
- Discount CalculatorFinance
- Margin CalculatorFinance
- Markup CalculatorFinance
- Simple Interest CalculatorFinance
- Inflation CalculatorFinance
- Investment CalculatorFinance
- Paycheck CalculatorFinance
- Currency ConverterFinance
- Depreciation CalculatorFinance
- VAT CalculatorFinance
- Rule of 72 CalculatorFinance
- Percentage CalculatorMath
- Age CalculatorMath
- Random Number GeneratorMath
- Fraction CalculatorMath
- Standard DeviationMath
- Exponent CalculatorMath
- Logarithm CalculatorMath
- Square Root CalculatorMath
- Ratio CalculatorMath
- Average CalculatorMath
- Prime Number CheckerMath
- GCD & LCM CalculatorMath
- Trigonometry CalculatorMath
- Matrix CalculatorMath
- Scientific NotationMath
- Date CalculatorDate & Time
- Days Between DatesDate & Time
- Time Zone ConverterDate & Time
- Day of WeekDate & Time
- Time DurationDate & Time
- Week NumberDate & Time
- Add/Subtract DaysDate & Time
- Business DaysDate & Time
- Unix TimestampDate & Time
- Countdown TimerDate & Time
- StopwatchDate & Time
- Pomodoro TimerDate & Time
- Length ConverterUnit Conversion
- Weight ConverterUnit Conversion
- Temperature ConverterUnit Conversion
- Volume ConverterUnit Conversion
- Area ConverterUnit Conversion
- Speed ConverterUnit Conversion
- Data Storage ConverterUnit Conversion
- Energy ConverterUnit Conversion
- Pressure ConverterUnit Conversion
- Fuel Economy ConverterUnit Conversion
- Angle ConverterUnit Conversion
- Power ConverterUnit Conversion
- Ohm's Law CalculatorScience & Engineering
- Molar Mass CalculatorScience & Engineering
- Dilution CalculatorScience & Engineering
- Decibel CalculatorScience & Engineering
- Parallel ResistanceScience & Engineering
- LED Resistor CalculatorScience & Engineering
- Wavelength-Frequency ConverterScience & Engineering
- pH CalculatorScience & Engineering
- PPI/DPI CalculatorDigital & Dev
- Aspect Ratio CalculatorDigital & Dev
- Subnet CalculatorDigital & Dev
- Number Base ConverterDigital & Dev
- Color Code ConverterDigital & Dev
- Chinese Zodiac CalculatorDaily Life
- Barcode Check DigitDaily Life
- Tile CalculatorDaily Life
- Paint CalculatorDaily Life
- Brick CalculatorDaily Life
- Blood Alcohol CalculatorDaily Life
- Electricity Cost CalculatorDaily Life
- Fuel Cost CalculatorDaily Life
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Calculators by Category
Explore 90 specialized calculators across 8 fields.
Health
BMI, Calorie, BMR, Body Fat, Pregnancy Due Date and more
Finance
Loan, Compound Interest, ROI, Investment, Currency and more
Math
Percentage, Age, Fraction, Standard Deviation, Average and more
Date & Time
D-Day, Days Between Dates, Timer, Stopwatch and more
Unit Conversion
Length, Weight, Temperature, Volume, Area, Speed and more
Science & Engineering
Ohm's Law, Molar Mass, Dilution, Decibel and more
Digital & Dev
PPI/DPI, Aspect Ratio, Subnet, Base Converter, Color Code
Daily Life
Electricity Cost, Tile, Paint, Alcohol, Fuel Cost and more
Popular Calculators
Jump right into our most-used calculators.
BMI Calculator
Enter height and weight to get your Body Mass Index (BMI), your underweight, normal, overweight or obese class and your healthy weight range.
Calorie Calculator
Calculate daily calorie needs (TDEE) from age, sex, height, weight and activity level. Free calorie calculator for weight loss or weight gain.
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) from age, sex, height and weight with the Mifflin-St Jeor formula. See the calories you burn at rest.
Pregnancy Due Date Calculator
Enter your last menstrual period or conception date to get your estimated due date (280 days), current pregnancy week and trimester.
Compound Interest Calculator
Enter principal, rate, term and frequency to see your final balance and total interest. Free compound interest calculator that shows compounding.
Loan Calculator
Enter loan amount, annual interest rate and term to get your monthly payment, total interest and amortization breakdown. Free loan calculator.
Percentage Calculator
Find X percent of Y, what percent one number is of another, and percentage increase or decrease. Free calculator for discounts, tips and tax.
Age Calculator
Enter your date of birth to get your exact age in years, months and days, plus total days lived and days until your next birthday. Free and online.
Random Number Generator
Pick random numbers in any min-to-max range. Choose integers or decimals, set how many, and allow duplicates or unique sets. Free RNG, no signup.
Date Calculator
Count the days remaining until a target date or elapsed since a past date. Free date calculator for birthdays, exams, events and milestones.
Days Between Dates
Calculate the exact number of days between two dates. Free date difference calculator for project durations, rental periods and age counting.
Why Patrache Studio Calc?
No sign-up, no installation required. Calculate directly in your browser and share results instantly. All calculations run on your device — your data never leaves your browser.
Completely Free
Access all 90 calculators with no limits, no paywalls, and no hidden fees.
Privacy First
All calculations run in your browser. Your input data is never sent to any server.
Mobile Friendly
Optimized for every screen — desktop, tablet, and smartphone.
20 Languages
Available in Korean, English, Japanese, and 17 more languages worldwide.
About Patrache Studio Calc
Patrache Studio Calc (calc.patrache.studio) is a free online calculator collection designed to help you with everyday and professional calculations quickly and accurately. As of 2026, we offer 90 calculators across 8 categories: Health, Finance, Math, Date & Time, Unit Conversion, Science & Engineering, Digital & Development, and Daily Life.
From health calculators like BMI, Calorie, and Body Fat to financial tools like Loan Interest, Compound Interest, and ROI — from math utilities like Percentage, Fraction, and Standard Deviation to date calculators like D-Day and Days Between Dates — every calculator uses verified formulas to deliver reliable results.
All calculations are processed directly in your browser, so your input data is never transmitted to external servers. No sign-up or app installation is needed — anyone can start using it right away, with an optimized experience on both desktop and mobile devices.