How-To Calculation Guides
Step-by-step guides that walk you through common calculations — with clear formulas, worked examples, and links to free calculators.
Finance(20)
How to Calculate Amortization Schedule
An amortization schedule breaks down each loan payment into principal and interest components over the life of the loan. It reveals how your balance decreases over time.
How to Calculate Break-Even Point
The break-even point is where total revenue equals total costs, meaning no profit or loss. It helps businesses set sales targets and pricing strategies.
How to Calculate Business Valuation
Business valuation estimates what a company is worth using financial metrics and industry benchmarks. The earnings multiplier method is one of the most common approaches.
How to Calculate Capital Gains Tax
Capital gains tax applies to the profit from selling an investment or asset. Rates depend on how long you held the asset and your income level.
How to Calculate Compound Interest
Compound interest is one of the most powerful concepts in finance — Albert Einstein reportedly called it the eighth wonder of the world. Whether you are saving for retirement, evaluating a loan, or comparing investment accounts, knowing how to calculate compound interest by hand gives you a deeper understanding of how your money grows over time.
How to Calculate Debt-to-Income Ratio
The debt-to-income ratio compares your monthly debt payments to your gross income. Lenders use it as a key factor in mortgage and loan approvals.
How to Calculate Discount
A discount calculation determines how much you save and the final sale price when a percentage is taken off. It is useful for shopping, business pricing, and promotions.
How to Calculate Income Tax
Income tax is calculated using progressive brackets where higher portions of income are taxed at higher rates. Understanding this helps with financial planning and tax optimization.
How to Calculate Inflation
An inflation calculator shows how purchasing power changes over time as prices rise. It helps with long-term financial planning and retirement projections.
How to Calculate Loan Payment
A loan payment calculator determines your fixed monthly payment on a personal, auto, or other installment loan. It uses the standard amortization formula.
How to Calculate Markup
Markup is the percentage added to the cost of a product to determine its selling price. It is fundamental to retail and wholesale pricing.
How to Calculate Mortgage Payment
A mortgage payment calculator helps you estimate your monthly housing cost based on loan amount, rate, and term. Understanding this calculation is essential before buying a home.
How to Calculate Net Worth
Net worth is the difference between what you own and what you owe. It provides the clearest single snapshot of your financial health.
How to Calculate Paycheck
A paycheck calculator estimates your take-home pay after federal, state, and FICA taxes plus other deductions. It helps you understand the gap between gross and net pay.
How to Calculate Profit Margin
Profit margin measures what percentage of revenue remains as profit after expenses. It is a key indicator of business efficiency and financial health.
How to Calculate Property Tax
Property tax is levied by local governments based on the assessed value of real estate. It funds schools, roads, and local services.
How to Calculate Return on Investment (ROI)
ROI measures the profitability of an investment as a percentage of its original cost. It is one of the most widely used metrics in finance and business.
How to Calculate Sales Tax
Sales tax is a consumption tax added to the purchase price of goods and services at the point of sale. Rates vary by state and locality.
How to Calculate Savings Growth
A savings calculator projects how your money grows over time with regular deposits and compound interest. It helps you plan for emergencies, goals, and retirement.
How to Calculate Tip
A tip calculator helps you quickly determine how much gratuity to leave based on your bill amount and desired percentage. It can also split the tip among a group.
Health & Fitness(10)
How to Calculate Blood Alcohol Content (BAC)
A BAC calculator estimates your blood alcohol level based on drinks consumed, body weight, sex, and time elapsed. It helps promote awareness of alcohol impairment.
How to Calculate Body Fat Percentage
A body fat calculator estimates the percentage of your body mass composed of fat using simple measurements. It provides a more nuanced health metric than weight alone.
How to Calculate Body Mass Index (BMI)
BMI is a simple calculation using height and weight to screen for weight categories. It is widely used by healthcare providers as an initial assessment tool.
How to Calculate Daily Calorie Needs
A calorie calculator estimates how many calories you need daily based on your metabolism and activity level. It is essential for managing weight and nutrition goals.
How to Calculate Daily Protein Intake
A protein calculator estimates your daily protein needs based on body weight, activity level, and fitness goals. Protein is crucial for muscle maintenance and overall health.
How to Calculate Daily Water Intake
A water intake calculator estimates how much water you should drink daily based on body weight and activity. Staying properly hydrated supports nearly every bodily function.
How to Calculate Ideal Body Weight
An ideal body weight calculator estimates a healthy weight based on height and sex using established medical formulas. It serves as a general guideline, not an absolute target.
How to Calculate Macronutrients
A macro calculator breaks your daily calories into grams of protein, carbohydrates, and fat. Balancing macros helps optimize performance, body composition, and health.
How to Calculate Target Heart Rate
A heart rate calculator determines your target exercise zones using the Karvonen method. Training in the right zone optimizes fat burn, endurance, or cardiovascular fitness.
How to Calculate Total Daily Energy Expenditure (TDEE)
TDEE represents the total calories your body burns in a day including all activity. It is the most important number for setting calorie targets for any fitness goal.
Math(8)
How to Calculate Exponents
Exponentiation multiplies a base number by itself a specified number of times. It is the foundation for exponential growth and scientific notation.
How to Calculate Logarithms
A logarithm answers the question: to what power must the base be raised to produce a given number? It is the inverse of exponentiation.
How to Calculate Mean, Median, and Mode
Mean, median, and mode are three ways to describe the center of a data set. Each provides different insight depending on data distribution.
How to Calculate Percentages
Percentages express a number as a fraction of 100. They are used everywhere from shopping discounts to scientific data.
How to Calculate Probability
Probability measures how likely an event is to happen, expressed as a number between 0 (impossible) and 1 (certain). It is the foundation of statistics and risk analysis.
How to Calculate Square Roots
A square root finds the value that, when multiplied by itself, produces the original number. It is one of the most fundamental operations in mathematics.
How to Calculate Standard Deviation
Standard deviation quantifies how spread out data points are from the average. A low value means data clusters near the mean; a high value means wide dispersion.
How to Solve Quadratic Equations
The quadratic formula solves any equation of the form ax^2 + bx + c = 0. It always works, even when factoring is difficult or impossible.
Everyday(4)
How to Calculate Fuel Cost
Fuel cost depends on three factors: distance, vehicle fuel efficiency, and fuel price. Dividing distance by MPG gives gallons needed.
How to Calculate Gas Mileage
Gas mileage (MPG) measures how many miles your vehicle travels per gallon of fuel. Higher MPG means better fuel efficiency and lower costs.
How to Calculate GPA
GPA is a weighted average that reflects academic performance across all courses. It uses a 4.0 scale where A=4, B=3, C=2, D=1, and F=0.
How to Calculate Your Grade
Grade calculation uses weighted averages where different assignment categories contribute different percentages to the final grade. Tests might be 50% while homework is 20%.
Conversions(5)
How to Convert Celsius to Fahrenheit
Celsius and Fahrenheit are the two most common temperature scales. The formula accounts for different zero points and degree sizes between the two scales.
How to Convert Centimeters to Inches
Centimeters and inches are common length units in metric and imperial systems. The exact conversion is 2.54 centimeters per inch.
How to Convert Kilograms to Pounds
Kilograms and pounds are the most common units of mass in the metric and imperial systems respectively. The conversion factor is 2.20462 pounds per kilogram.
How to Convert Liters to Gallons
Liters and gallons are common volume units in metric and imperial systems. The US gallon equals 3.78541 liters.
How to Convert Meters to Feet
Meters and feet are both units of length, with meters used in the metric system and feet in the imperial system. The conversion factor is 3.28084 feet per meter.
Construction(5)
How to Calculate Concrete Needed
Concrete is sold by the cubic yard, so you need to calculate the volume of your project area. Converting from cubic feet to cubic yards requires dividing by 27.
How to Calculate Decking Materials
Decking material calculations depend on total deck area, board dimensions, and spacing gaps. Always account for waste from cuts and imperfections.
How to Calculate Flooring Needed
Flooring calculations start with measuring total square footage and adding a waste factor for cuts and mistakes. Different patterns require different waste allowances.
How to Calculate Paint Needed
Paint estimation involves calculating total wall area, subtracting doors and windows, and dividing by the coverage rate. Most paints cover about 350 sq ft per gallon.
How to Calculate Square Footage
Square footage is the area of a space measured in square feet. It is the standard measurement for real estate, flooring, and construction in the US.
Physics & Science(4)
How to Calculate Acceleration
Acceleration measures how quickly velocity changes over time. It is a vector quantity with both magnitude and direction.
How to Calculate Force
Newton's Second Law states that force equals mass times acceleration. It is the cornerstone of classical mechanics.
How to Calculate Using Ohm's Law
Ohm's Law states that voltage equals current times resistance. It is the most fundamental equation in electronics and electrical engineering.
How to Calculate Velocity
Velocity measures how fast something moves in a specific direction. It is calculated by dividing displacement by time.
Food & Cooking(2)
How to Convert Cooking Units
Cooking units vary by country and recipe tradition. The most common conversions involve cups, tablespoons, teaspoons, milliliters, and grams.
How to Scale a Recipe
Recipe scaling multiplies or divides all ingredient amounts by a common factor. The key is maintaining the ratio between ingredients.
Sports(2)
How to Calculate Calories Burned
Calories burned during exercise depend on the activity intensity (MET), your body weight, and duration. MET values are standardized for hundreds of activities.
How to Calculate Running Pace
Running pace tells you how long it takes to cover each mile or kilometer. It is the primary metric runners use to gauge effort and set race strategies.