Investing $1,000 every month at a 7% average annual return grows to $520,927 in 20 years. You contribute $240,000 in total, and compound interest adds $280,927.

Key Numbers

• •Total after 20 years at 7%: $520,927
• •Total contributions: $240,000
• •Interest earned: $280,927
• •Starting with a $10,000 lump sum as well: $561,314