Finance calculator
Interest Calculator
Calculate simple or compound interest, estimate your final balance, and see how much growth comes from interest over time.
Simple interest
Compound interest
Future value
Calculator
Enter your numbers
Choose simple or compound mode, then adjust rate and time to estimate growth.
Inputs
Choose your interest type and adjust the inputs below.
Results
Balanced
Interest summary
Quick take
This interest scenario shows balanced growth, with time and compounding creating meaningful gains over the full period.
Interest Type
Compound
Time Horizon
10.00 Years
Check values
Enter valid values greater than or equal to zero to calculate interest.
How interest growth is calculated
Simple and compound interest do not grow the same way
Simple interest grows only from the original principal. Compound interest grows from both the original principal and previously earned interest.
Simple Interest
Principal × Rate × Time
Compound Interest
Principal × (1 + Rate / Frequency)^(Frequency × Time)
Interest Earned
Final Balance − Starting Principal
When to use it
Useful for savings, investing, and rate comparisons
Compare simple vs compound growth
See how much more compounding can grow a balance compared with simple interest over the same time.
Estimate future balance
Use interest rate and time assumptions to estimate where a current balance may end up in the future.
Understand what drives growth
Explore how small changes in rate, frequency, or time affect the amount of interest earned.
Interest FAQ
Frequently asked questions
Quick answers to common questions about this calculator and how to use it.
What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal, while compound interest earns or charges interest on both the principal and accumulated interest.
Can this calculator be used for savings and loans?
Yes. Interest calculators are useful for estimating growth on savings and investments as well as understanding borrowing costs.
Why does compounding frequency matter?
More frequent compounding can increase growth on savings and investments, or increase the total cost of borrowing, depending on how interest is applied.
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