Investing basics

What is Investing basics?

Investing basics covers a specific, recurring money problem: understanding compounding and return math before putting money to work. Instead of doing the math by hand or guessing, the tools on this page – Compound Interest Calculator, Retirement Calculator, and ROI Calculator – give you an exact number in seconds, using the same formulas a financial professional would use.

Each tool listed here targets a different angle on investing basics. Start with whichever one matches your immediate question; the calculators are independent, so you can jump between them without losing any inputs, and every result updates instantly as you change a number.

Tools in this topic

• Compound Interest Calculator – See how your investments grow over time with daily, monthly, or annual compounding. Model contributions, inflation, taxes, and time horizons from 1 to 50 years.
• Retirement Calculator – Calculate how much you need to retire, how much you should save monthly, and whether you are on track. Includes 401(k) match modeling, Social Security estimatio
• ROI Calculator – Calculate return on investment for stocks, real estate, business projects, and marketing campaigns. Includes annualized ROI, CAGR, and comparison between multip

How to choose

• If you need a quick, one-off number, open the first tool above and enter your figures.
• If you’re comparing scenarios, open the tool in two browser tabs and change one variable at a time.
• If you want the full picture, check the Related Tools section on each calculator page for adjacent tools that cover the next step.