Investing $300 every month at a 7% average annual return grows to $365,991 in 30 years. You contribute $108,000 in total, and compound interest adds $257,991.

Key Numbers

• •Total after 30 years at 7%: $365,991
• •Total contributions: $108,000
• •Interest earned: $257,991
• •Starting with a $10,000 lump sum as well: $447,156