Free Online Calculators
508+ calculators for finance, health, math, engineering, and more. No signup required.
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Popular Calculators
Most-used tools across all categories
MAP Calculator - Mean Arterial Pressure
Calculate Mean Arterial Pressure (MAP) from systolic and diastolic blood pressure readings. Professional medical tool for cardiovascular assessment, organ perfusion evaluation, and clinical decision-making.
Health →BSA Calculator
Calculate Body Surface Area (BSA) using validated medical formulas including Du Bois, Mosteller, and Haycock. Essential for chemotherapy dosing, cardiac assessments, and clinical calculations with detailed medical reference content.
Health →Weight Gain Calculator
Calculate your personalized weight gain plan with calorie targets, macro breakdown, and healthy timeline recommendations for sustainable muscle building.
Health →BMI Calculator for Men
Professional BMI calculator designed specifically for men's unique physiological characteristics. Accounts for male muscle mass distribution, fat storage patterns, and age-related body composition changes with personalized fitness recommendations.
Health →Trigonometry Calculator
Calculate trigonometric functions including sine, cosine, tangent, and their inverses. Perfect for students, engineers, and professionals with detailed explanations and formulas.
Math →BMI Calculator for Women
Professional BMI calculator designed specifically for women's health needs with female-specific health considerations, reproductive health guidance, and personalized recommendations based on female physiology.
Health →Wheel Size Calculator
Calculate the impact of changing wheel sizes on tire specifications, speedometer accuracy, and vehicle performance. Professional tool for wheel upgrades and plus sizing projects with comprehensive analysis.
Automobile →Calorie Deficit Calculator for Women
Calculate optimal calorie deficits specifically designed for female physiology. Account for hormonal fluctuations, menstrual cycles, and women's unique metabolic characteristics for safe, sustainable weight loss.
Health →Recently Added
Fresh calculators just added to our collection
RV/Van Life Solar Panel Sizing Calculator
Calculate the optimal solar panel wattage for your RV, camper van, or off-grid system. Size your solar array based on daily energy needs, sun hours, and system efficiency.
RV/Van Life Battery Bank Sizing Calculator
Calculate the optimal battery bank capacity for your RV or van. Size lithium or AGM batteries based on daily usage, depth of discharge, and days of autonomy.
RV/Van Life Electrical Load Calculator
Calculate your RV or van daily electrical load. Add appliances, estimate watt-hours, and determine total power needs for off-grid solar and battery system planning.
RV/Van Life Propane Usage Calculator
Calculate your RV or van propane consumption for heating, cooking, fridge, and water heater. Estimate tank duration and monthly propane costs for off-grid living.
RV/Van Life Water Tank Duration Calculator
Calculate how long your RV or van fresh water tank will last based on usage patterns. Plan water refills for boondocking and dry camping trips.
RV/Van Life Wire Gauge Calculator
Calculate the correct wire gauge (AWG) for 12V and 24V DC circuits in your van or RV. Prevent voltage drop and ensure safe electrical installations.
Why Complete Calculators?
Accurate Formulas
Each calculator uses verified formulas from authoritative sources. Check our sources section on each tool.
Private & Secure
Calculations happen in your browser. We don't store your data or require any login.
Works Everywhere
Mobile-friendly design. Use on your phone, tablet, or desktop - no app download needed.
Frequently Asked Questions
Are these calculators really free?
Yes, all 508+ calculators are completely free to use. No subscription, no hidden fees, no signup required. We support the site through minimal, non-intrusive advertising.
How accurate are the calculations?
We use industry-standard formulas and cite our sources on each calculator page. For professional or legal decisions, we recommend consulting with a qualified professional.
Is my data private?
All calculations are performed locally in your browser. Your input data is never sent to our servers or stored anywhere. Close the page and your data is gone.
Can I suggest a new calculator?
We're always adding new calculators based on user needs. Contact us with your suggestion and we'll consider adding it to our collection.
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