Investing $300 every month at a 7% average annual return grows to $156,278 in 20 years. You contribute $72,000 in total, and compound interest adds $84,278.

Key Numbers

• •Total after 20 years at 7%: $156,278
• •Total contributions: $72,000
• •Interest earned: $84,278
• •Starting with a $10,000 lump sum as well: $196,665