Savings CalculatorFree online financial calculator — instant results, no sign-up
How savings grow with deposits, interest and tax.
Estimates only, based on the inputs and assumptions shown. This is not financial, investment, tax, or legal advice. Prices, rates and local rules may change; crypto scenarios do not predict returns. Confirm important decisions with a qualified professional.
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How the result changes with initial deposit
Each row below was calculated with this tool, keeping every other input at its default and changing only initial deposit from half to one and a half times the default value. Use it to see how sensitive the answer is before you enter your own numbers.
| Initial deposit ($) | End balance | Deposits | Interest (after tax) |
|---|---|---|---|
| 2,500 | $16,277.44 | $14,500.00 | $1,777.44 |
| 3,750 | $17,798.25 | $15,750.00 | $2,048.25 |
| 5,000 (default) | $19,319.07 | $17,000.00 | $2,319.07 |
| 6,250 | $20,839.89 | $18,250.00 | $2,589.89 |
| 7,500 | $22,360.70 | $19,500.00 | $2,860.70 |
About the Savings Calculator
This calculator projects the growth of a savings account over time with regular monthly contributions and compound interest. It also estimates the impact of annual income tax on your earned interest to show your actual net returns.
- Initial deposit
- The lump sum starting balance placed in the account, in dollars (typically $0 or greater).
- Monthly deposit
- The amount added to the account at the end of each month, in dollars (typically $0 or greater).
- APY
- Annual Percentage Yield, reflecting the compounding interest rate offered by the institution, as a percentage (e.g., 0% to 15%).
- Years
- The total investment horizon in whole or fractional years (e.g., 1 to 50 years).
- Tax on interest
- The effective tax rate applied to interest earnings, matching your income tax bracket, as a percentage (typically 0% to 50%).
Formula and method
r = ((1 + APY / 100)^(1 / 12) - 1) × (1 - Tax / 100) End balance = P × (1 + r)^n + PMT × (((1 + r)^n - 1) / r) Deposits = P + PMT × n Interest (after tax) = End balance - Deposits
- PInitial deposit amount
- PMTMonthly deposit amount
- APYAnnual Percentage Yield
- TaxTax rate applied to interest income
- rEffective monthly after-tax interest rate
- nTotal number of months (Years × 12)
The tool converts the annual percentage yield (APY) to an effective monthly compounding rate, then discounts that rate by the specified tax percentage. It evaluates the future value of the initial balance and recurring monthly deposits over the total number of months, formatting the final balance, total principal deposited, and net interest rounded to two decimal places.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Initial deposit5000 $
- Monthly deposit200 $
- APY4 %
- Years5 years
- Tax on interest0 %
Results
- End balance$19,319.07
- Deposits$17,000.00
- Interest (after tax)$2,319.07
How to use the Savings Calculator
- 1Convert the APY to an effective monthly rate and deduct the tax percentage.
- 2Multiply the number of years by 12 to find the total number of monthly compounding periods.
- 3Calculate the total future value of the initial deposit and recurring monthly additions using the net monthly rate.
- 4Subtract total cumulative deposits from the ending balance to determine total after-tax interest earned.
Reading your result
Review the ending balance to see your projected account value at the end of the term. Comparing total deposits with net interest highlights how much of your final balance stems from your own savings versus compound investment returns after taxes.
Limitations
The calculation assumes a constant APY and fixed monthly contribution amount across the entire duration. In practice, bank interest rates fluctuate, and taxes on savings account interest are generally assessed and deducted annually rather than adjusted continuously into the monthly compounding rate.
Common questions
What is the difference between APR and APY?+
APR represents the simple annual interest rate without compounding, whereas APY accounts for the compounding frequency, representing the actual annual return earned on your funds.
How does tax affect my interest earnings?+
In most jurisdictions, interest earned in standard savings accounts is treated as ordinary taxable income. Higher tax rates lower the effective yield compounding in your account.
Are deposits assumed to occur at the beginning or end of the month?+
The model uses an ordinary annuity convention, assuming regular monthly contributions are made at the end of each monthly period.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.