The foundation
What is compound interest?
See how interest can earn interest, how it differs from simple interest, and which assumptions change an estimate.
Learning center
Compound interest, explained plainly.
Understand the parts of a compound-growth estimate before changing the numbers. Each guide connects the idea to an example you can reproduce in the calculator.
Try the calculatorStart with the question you have
Regular saving
How monthly contributions grow
Separate the amount you deposit from projected growth and see why time changes the result.
Rate mechanics
Compounding frequency explained
Compare annual, monthly, and daily compounding while keeping the nominal rate the same.
Worked numbers
Compound interest examples
Reproduce three scenarios and learn what each result does and does not show.
How to read a projection
A useful result separates the starting amount, later deposits, and projected interest. It also states the rate, time horizon, contribution timing, and compounding frequency. A larger ending balance can come from putting in more money, allowing more time, assuming a higher rate, or compounding more often. Those causes should not be treated as interchangeable.
Every page in this learning center uses fixed-rate educational examples. Real savings and investment products may apply fees, taxes, changing rates, exact calendar-day rules, or investment losses.