$5,000 invested at 7% annual return compounded monthly grows to $10,048 in 10 years — $5,048 of that is compound interest. Adding $200 monthly contributions would grow the total to $44,665.

Key Numbers

• •Starting amount: $5,000
• •Value after 10 years at 7%: $10,048
• •Interest earned: $5,048
• •With $200/month added: $44,665
• •At 7%, money doubles roughly every 10.3 years (rule of 72)