Compound interest calculator

How a portfolio grows with regular contributions, and what a difference in return is worth.

Inputs

Starting amount, $

Monthly contribution, $

A minus means a monthly withdrawalTerm, years

A whole number from 1 to 50

Return, % a year

Low

Base

High

Market

From −50 to 100%. The US market has returned about 10% a year.

Reinvest incomeIncome stays in the portfolio and earns more income.Income tax, %

Taken once from the total income; 0% means ignore it.Inflation, % a year

Target amount, $

In 10 years: $0 at 15% a year. You will contribute $0 in total.

● Low · 10%

● Base · 15%

● High · 20%

● Market · 10%

The dashed line is the money put in.

The calculation is illustrative. Returns are not guaranteed.