How to use the savings interest calculator
Enter the opening balance and annual interest rate, then choose how often interest compounds. The result separates the original deposit from modeled interest earned.
Compound-balance formula
This version does not include recurring deposits. Use the Compound Interest Calculator when you want to model regular contributions.
Example: Ben leaves interest in the account
Ben starts with $10,000 and assumes a 4% nominal annual rate, compounded annually for three years. With no withdrawals or further deposits, the ending balance is $10,000 × 1.04³ = $11,248.64.
The $1,248.64 difference is modeled interest. Choose monthly compounding only when that matches the account terms; changing the frequency changes the estimate.
Keep the interest rate and APY distinct
This tool uses a nominal annual interest rate and a separate compounding frequency. If you only have a quoted APY, choose annual compounding to model that annual yield.
The estimate grows a starting balance without further deposits. Use the Compound Interest Calculator to include recurring contributions.
Separate your deposits from interest earned
This tool grows a single starting balance. Interest earned is the ending balance minus that starting amount. Compare the interest figure when testing rates or compounding frequencies.
This projection holds the rate constant and does not model deposits or withdrawals during the term. Use the Compound Interest Calculator for regular contributions and the APY Calculator to convert a nominal rate into an effective annual yield.
Assumptions and limitations
What the estimate assumes
Variable rates, account fees, taxes, withdrawals, and deposits are not included.
Sources and reference material
Savings Interest Calculator FAQs
Does compounding frequency matter?
Yes. With the same nominal annual rate, more frequent compounding can produce a slightly higher effective annual yield.
Does this calculator use APY?
The input is a nominal annual rate plus compounding frequency. If your bank quotes APY, use the APY Calculator or a model designed to use APY directly.
Can I add monthly deposits?
Use the Compound Interest Calculator for recurring contributions.
Does this include taxes on interest?
No.
What is the difference between interest earned and contributions?
Contributions are money you add to the account. Interest earned is the growth produced by the modeled rate on eligible balances.
Can a savings account rate change?
Yes, many savings rates are variable. The calculator holds the entered rate constant for the scenario, so recalculate when the account rate changes.
Educational estimate. Actual savings interest depends on the account's rate, APY, balance method, fees, and crediting terms.