Savings Account Interest Calculator

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Savings Account Interest Calculator
DailyMonthlyQuarterlyAnnually
Results:
Total Savings Balance:$ 0.00
Total Principal + Deposits:$ 0.00
Total Interest Earned:$ 0.00
function calculateSavings(){var p=parseFloat(document.getElementById('principal').value);var pmt=parseFloat(document.getElementById('monthly_pmt').value);var r=parseFloat(document.getElementById('interest_rate').value)/100;var t=parseFloat(document.getElementById('years').value);var n=parseInt(document.getElementById('comp_freq').value);if(isNaN(p)||isNaN(pmt)||isNaN(r)||isNaN(t)){alert('Please enter valid numeric values');return;}var totalMonths=t*12;var periodicRate=r/n;var totalPeriods=n*t;var fvPrincipal=p*Math.pow((1+periodicRate),totalPeriods);var monthlyRate=(Math.pow((1+periodicRate),(n/12)))-1;var fvAnnuity=pmt*(Math.pow((1+monthlyRate),totalMonths)-1)/monthlyRate;var totalBalance=fvPrincipal+fvAnnuity;var totalInvested=p+(pmt*totalMonths);var totalInterest=totalBalance-totalInvested;document.getElementById('totalBalance').innerHTML=totalBalance.toLocaleString(undefined,{minimumFractionDigits:2,maximumFractionDigits:2});document.getElementById('totalPrincipal').innerHTML=totalInvested.toLocaleString(undefined,{minimumFractionDigits:2,maximumFractionDigits:2});document.getElementById('totalInterest').innerHTML=totalInterest.toLocaleString(undefined,{minimumFractionDigits:2,maximumFractionDigits:2});if(document.getElementById('showSteps').checked){var steps="Step-by-Step Calculation:
";steps+="1. Principal growth: $"+p.toFixed(2)+" × (1 + "+r+"/"+n+")^"+totalPeriods+" = $"+fvPrincipal.toFixed(2)+"
";steps+="2. Monthly deposits growth: $"+pmt.toFixed(2)+" annuity over "+totalMonths+" months = $"+fvAnnuity.toFixed(2)+"
";steps+="3. Total = $"+fvPrincipal.toFixed(2)+" + $"+fvAnnuity.toFixed(2)+" = $"+totalBalance.toFixed(2);document.getElementById('stepsOutput').innerHTML=steps;document.getElementById('stepsOutput').style.display='block';}else{document.getElementById('stepsOutput').style.display='none';}}

How to Use the Savings Account Interest Calculator

Planning for your financial future requires precision. Our savings account interest calculator helps you project the future value of your savings by accounting for initial deposits, recurring monthly contributions, and the power of compound interest. Whether you are saving for a down payment on a house, an emergency fund, or a vacation, this tool provides a clear picture of how your money grows over time.

Initial Deposit
The starting balance of your savings account. This is the lump sum you already have available to earn interest from day one.
Monthly Contribution
The amount you plan to add to your account every month. Regular contributions significantly accelerate growth through the "annuity" effect.
Annual Interest Rate (APY)
The annual percentage yield offered by your bank. High-yield savings accounts typically offer higher rates than standard accounts.
Compounding Frequency
How often the bank calculates interest and adds it to your balance. Most modern savings accounts compound interest daily or monthly.

The Math Behind Compound Interest

Compound interest is often called the "eighth wonder of the world" because it allows you to earn interest on your interest. Our savings account interest calculator uses a combination of the compound interest formula and the future value of an ordinary annuity formula.

A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) – 1) / (r/n)]

  • A = The future value of the investment/overall balance
  • P = The principal investment amount (initial deposit)
  • r = The annual interest rate (decimal)
  • n = The number of times that interest is compounded per year
  • t = The number of years the money is invested for
  • PMT = The monthly contribution amount

Calculation Example

Scenario: You open a high-yield savings account with $5,000. You commit to depositing $200 every month for 10 years. The bank offers a 4.0% APY compounded monthly.

Step-by-step breakdown:

  1. Initial Deposit Growth: $5,000 grows to $7,454.16 over 10 years.
  2. Monthly Contributions: $200 deposited monthly for 120 months grows to $29,446.86.
  3. Total Invested: $5,000 + ($200 × 120) = $29,000.
  4. Total Interest: $36,901.02 (Final Balance) – $29,000 (Invested) = $7,901.02.
  5. Final Result: Your total savings after 10 years would be $36,901.02.

Common Savings Questions

What is the difference between APR and APY?

APR (Annual Percentage Rate) does not account for compounding within the year, whereas APY (Annual Percentage Yield) does. When comparing savings accounts, always look at the APY, as it reflects the true amount of interest you will earn.

How does compounding frequency affect my savings?

The more frequently interest is compounded, the faster your balance grows. Daily compounding is better for the saver than monthly or annual compounding because the interest begins earning its own interest sooner. However, on smaller balances, the difference is often only a few dollars per year.

Are savings account earnings taxable?

In most cases, yes. The interest you earn in a standard or high-yield savings account is considered taxable income by the IRS. Your bank will typically send you a Form 1099-INT at the end of the year if you earned more than $10 in interest.

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