Calculator Guides
Simple explanations to help users understand common formulas and results.
Mortgage Basics
Payment depends mainly on principal, interest rate and term.
ROI Basics
ROI compares net gain with the original investment.
Age Calculations
Exact age may be expressed in years, months and days.
BMI Basics
BMI is a broad screening estimate based on height and weight.
Ohm’s Law
Voltage equals current multiplied by resistance.
Percentage Formula
Percentage of a number = percentage ÷ 100 × base.