Algebra
Compound Interest Calculator
Model investment growth with compound interest. Calculate final amount, total interest earned, and year-by-year growth using the compound interest formula A = P(1 + r/n)^(nt).
Examples:
Formula Reference
Linear Equation
ax + b = c → x = (c−b)/a
Quadratic Formula
x = (−b ± √(b²−4ac)) / 2a
Discriminant
Δ = b² − 4ac
Vertex Form
y = a(x−h)² + k
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Solution Methodology
01
Enter Principal & Rate
Provide the starting amount P and the annual interest rate r as a percentage.
02
Set Compounding Frequency
Choose how often interest compounds: annually, quarterly, monthly, or daily.
03
Compute & Compare
Evaluate A = P(1+r/n)^(nt) and show the year-by-year balance table vs simple interest.
Common Questions
What is the compound interest formula?
A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual rate as a decimal, n is the number of compounding periods per year, and t is time in years. The more frequently interest compounds, the higher the final amount.
How does compound interest differ from simple interest?
Simple interest earns interest only on the original principal (I = Prt). Compound interest earns interest on both the principal and previously accumulated interest, causing exponential growth. Over long periods the difference can be dramatic.