Free tool
What does money do when you leave it alone?
Start with an amount, add a little every month, pick a rate and a number of years. The navy part of each bar is what you put in. The gold part is what interest added on top. Watch the gold grow faster than the navy the longer you wait.
After 10 years: $4,047. You put in $3,100; interest added $947.
Quick tries
Year 10
- Total
- $4,047
- Put in
- $3,100
- Interest
- $947
The gold passes the navy in year 25.
Interest compounds monthly; the monthly amount is added after each month’s interest. No taxes, fees, or inflation. A model for learning, not a forecast.
What this teaches
Time does more work than the rate does. A small amount started early beats a larger amount started late, and the difference shows up in the gold, not the navy.
Taught properly in Unit 3.5 · Saving and the Time Factor →For teachers
Put it on the board, change one number at a time, and ask the class to predict before you press. Free to use in any classroom.
What a teacher gets with the program →For families
The five-day version of this conversation is The $100 Week™. No account, no download, and your child plays it, not you.
See the family path →Also free: Savings goal calculator →