:root {
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color: var(–text-color);
line-height: 1.6;
margin: 0;
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}
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margin: 20px auto;
padding: 20px;
background-color: #fff;
border-radius: 8px;
box-shadow: 0 4px 15px var(–shadow-color);
}
header {
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color: white;
padding: 20px;
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text-align: center;
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}
header h1 {
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font-weight: 600;
}
.calculator-section {
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flex-wrap: wrap;
gap: 30px;
margin-bottom: 40px;
}
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min-width: 300px;
}
.loan-calc-container {
background-color: #fff;
padding: 25px;
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box-shadow: 0 2px 10px var(–shadow-color);
}
.input-group {
margin-bottom: 20px;
position: relative;
}
.input-group label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: var(–label-color);
}
.input-group input[type=”number”],
.input-group select {
width: calc(100% – 22px);
padding: 10px 12px;
border: 1px solid var(–border-color);
border-radius: 5px;
font-size: 1em;
box-sizing: border-box;
}
.input-group input[type=”number”]:focus,
.input-group select:focus {
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bottom: -18px;
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.button-group button {
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font-size: 1em;
font-weight: 600;
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transition: background-color 0.3s ease, transform 0.2s ease;
white-space: nowrap;
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color: white;
}
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background-color: #6c757d;
color: white;
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transform: translateY(-2px);
}
.btn-copy {
background-color: #ffc107;
color: #212529;
margin-left: auto;
}
.btn-copy:hover {
background-color: #e0a800;
transform: translateY(-2px);
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#result-summary {
background-color: var(–success-color);
color: white;
padding: 15px 20px;
border-radius: 5px;
margin-top: 20px;
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box-shadow: 0 2px 8px rgba(40, 167, 69, 0.4);
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margin-bottom: 30px;
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.formula-explanation {
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margin-top: 20px;
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margin-top: 30px;
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height: auto;
}
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font-size: 0.9em;
color: #6c757d;
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table {
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caption {
font-size: 1.2em;
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color: var(–primary-color);
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th {
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color: white;
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td {
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box-shadow: none;
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.related-links {
margin-top: 20px;
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padding: 15px;
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color: var(–primary-color);
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font-size: 0.9em;
color: #6c757d;
margin-top: 5px;
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@media (min-width: 768px) {
.calculator-section {
flex-direction: row;
}
.loan-calc-container {
flex: 1;
}
.results-container, .chart-container, table {
flex: 1;
}
.calculator-section > div {
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}
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.container {
margin: 10px;
padding: 15px;
}
header h1 {
font-size: 1.8em;
}
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flex-direction: column;
}
.button-group {
justify-content: center;
}
.btn-copy {
margin-left: 0;
width: 100%;
}
}
Bank Savings Calculator
Estimate the future value of your savings with compound interest.
Savings Input
The starting amount in your savings account.
Regular amount added to your savings each month.
The yearly interest rate your savings account earns.
How long you plan to save.
Annually
Semi-annually
Quarterly
Monthly
Daily
How often interest is calculated and added to your principal.
Your Savings Projection
—
—
—
FV = P(1 + r/n)^(nt) + PMT * [((1 + r/n)^(nt) – 1) / (r/n)]
Where:
- FV = Future Value
- P = Initial Deposit
- PMT = Periodic Contribution (Monthly Contribution)
- r = Annual Interest Rate (decimal)
- n = Number of times interest is compounded per year
- t = Number of years
| Year | Beginning Balance | Contributions | Interest Earned | Ending Balance |
|---|
Understanding the Bank Savings Calculator
A bank savings calculator is an indispensable tool for anyone looking to understand and project the growth of their savings over time. Whether you’re saving for a down payment, retirement, or an emergency fund, this calculator helps visualize how your money can grow through the power of compound interest and regular contributions. It demystifies financial planning, making it easier to set realistic goals and track your progress towards them. By inputting key variables, you get immediate insights into potential future wealth, helping you make informed decisions about your financial strategy.
This bank savings calculator is designed for a broad audience, from young individuals starting their financial journey to seasoned investors looking to optimize their savings vehicles. It’s particularly useful for comparing different savings scenarios, such as varying interest rates or contribution amounts, to see which strategy yields the best results. It helps answer questions like: “How much will I have if I save $100 a month for 5 years at 5% interest?” or “What initial deposit do I need to reach $10,000 in 3 years?”. Understanding these projections is crucial for effective financial management.
A common misconception about saving is that only large initial deposits or extremely high interest rates lead to significant wealth. In reality, consistent, regular contributions, even small ones, combined with the effects of compounding over time, can lead to substantial growth. This bank savings calculator highlights this effect, showing how even modest monthly additions can significantly boost your savings total. Another misconception is that interest rates are static; while this calculator uses a fixed rate for projection, in reality, rates can fluctuate, which is an important factor to consider in long-term financial planning.
Bank Savings Calculator Formula and Mathematical Explanation
The bank savings calculator utilizes a compound interest formula combined with the future value of an annuity to calculate the projected balance. It accounts for an initial lump sum deposit and any subsequent regular contributions, applying the specified interest rate and compounding frequency.
The core formula for the future value (FV) of a savings plan is a combination of two parts:
- The future value of the initial deposit (P).
- The future value of a series of regular contributions (PMT), often called an annuity.
The formula for the future value of the initial deposit is:
FV_initial = P * (1 + r/n)^(n*t)
The formula for the future value of the periodic contributions (annuity) is:
FV_annuity = PMT * [((1 + r/n)^(n*t) - 1) / (r/n)]
The total future value is the sum of these two components:
FV_total = FV_initial + FV_annuity
FV_total = P * (1 + r/n)^(n*t) + PMT * [((1 + r/n)^(n*t) - 1) / (r/n)]
Here’s a breakdown of the variables used in the bank savings calculator:
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| P (Initial Deposit) | The principal amount initially deposited into the savings account. | Currency (e.g., USD, EUR) | $0.01 – $1,000,000+ |
| PMT (Monthly Contribution) | The amount added to the savings account on a regular basis (monthly in this calculator). | Currency (e.g., USD, EUR) | $0.00 – $10,000+ |
| r (Annual Interest Rate) | The nominal annual interest rate offered by the savings account. | Decimal (e.g., 0.05 for 5%) | 0.001 – 0.20 (0.1% – 20%) |
| n (Compounding Frequency) | The number of times the interest is compounded per year. | Integer (1, 2, 4, 12, 365) | 1 (Annually), 12 (Monthly), 365 (Daily) |
| t (Number of Years) | The total duration for which the savings will grow. | Years | 1 – 100+ |
| FV (Future Value) | The total projected amount in the savings account at the end of the term. | Currency (e.g., USD, EUR) | Calculated |
| Total Interest Earned | The cumulative interest gained over the savings period. | Currency (e.g., USD, EUR) | Calculated |
| Total Principal Contributed | Sum of the initial deposit and all monthly contributions. | Currency (e.g., USD, EUR) | Calculated |
Practical Examples (Real-World Use Cases)
Let’s explore how the bank savings calculator can be applied in real-world scenarios.
Example 1: Saving for a Down Payment
Sarah wants to save for a down payment on a house in 5 years. She has $5,000 saved already and plans to add $300 from her monthly budget. She found a high-yield savings account offering an annual interest rate of 4.8% compounded monthly.
- Initial Deposit (P): $5,000
- Monthly Contribution (PMT): $300
- Annual Interest Rate (r): 4.8% (0.048)
- Number of Years (t): 5
- Compounding Frequency (n): 12 (Monthly)
Using the bank savings calculator with these inputs:
- Total Principal Contributed: $5,000 + ($300 * 12 months/year * 5 years) = $5,000 + $18,000 = $23,000
- Total Interest Earned: Approximately $3,079.54
- Future Value of Savings: Approximately $26,079.54
Interpretation: Sarah can project having over $26,000 saved in 5 years, which significantly helps her goal of accumulating a down payment. This calculation provides a concrete target and motivates her to stick to her savings plan.
Example 2: Building an Emergency Fund
John is starting to build an emergency fund. He makes an initial deposit of $1,000 and commits to saving $150 per month. He anticipates an average annual interest rate of 3.5% compounded quarterly over the next 3 years.
- Initial Deposit (P): $1,000
- Monthly Contribution (PMT): $150
- Annual Interest Rate (r): 3.5% (0.035)
- Number of Years (t): 3
- Compounding Frequency (n): 4 (Quarterly)
Inputting these figures into the bank savings calculator:
- Total Principal Contributed: $1,000 + ($150 * 12 months/year * 3 years) = $1,000 + $5,400 = $6,400
- Total Interest Earned: Approximately $340.89
- Future Value of Savings: Approximately $6,740.89
Interpretation: John can see that his consistent savings habit, combined with compound interest, will help him build a solid emergency fund of nearly $6,800 within three years. This provides peace of mind knowing he has a financial cushion.
How to Use This Bank Savings Calculator
Using the bank savings calculator is straightforward. Follow these steps to get your personalized savings projection:
- Enter Initial Deposit: Input the lump sum amount you are starting with in your savings account.
- Specify Monthly Contribution: Enter the amount you plan to add to your savings regularly each month. If you don’t plan to contribute monthly, enter ‘0’.
- Set Annual Interest Rate: Input the expected annual interest rate of your savings account in percentage form (e.g., 4.5 for 4.5%).
- Determine Number of Years: Enter the total time period (in years) you intend to save.
- Choose Compounding Frequency: Select how often your bank calculates and adds interest to your principal (e.g., Monthly, Quarterly, Annually).
- Click ‘Calculate’: Once all fields are populated, click the “Calculate” button.
Interpreting the Results:
- Future Value of Savings: This is the main result, showing the total amount you can expect to have in your account after the specified period.
- Total Interest Earned: This figure illustrates the growth generated purely from interest over time, highlighting the benefit of compounding.
- Total Principal Contributed: This is the sum of your initial deposit and all your regular contributions, showing how much you’ve personally put into the account.
- Yearly Breakdown Table: Provides a year-by-year view of your savings growth, showing balances, contributions, and interest earned for each year.
- Growth Chart: Visually represents the growth trajectory of your savings, making it easy to see the impact of compounding over time.
Decision-Making Guidance:
Use the calculator to:
- Set achievable savings goals.
- Compare the potential returns of different savings accounts or strategies.
- Adjust your monthly contributions or savings timeline to meet specific financial targets.
- Understand the long-term impact of even small changes in interest rates or contribution amounts.
Remember to use the “Reset” button to clear fields and start a new calculation. The “Copy Results” button is useful for saving or sharing your projection summary.
Key Factors That Affect Bank Savings Calculator Results
Several critical factors influence the outcomes generated by a bank savings calculator. Understanding these can help you refine your savings strategy and achieve your financial goals more effectively.
- Interest Rate (r): This is perhaps the most significant factor. A higher annual interest rate means your money grows faster due to compound interest. Even small differences in rates can lead to large discrepancies in future value over long periods. Look for accounts with competitive rates.
- Compounding Frequency (n): Interest compounded more frequently (e.g., daily vs. annually) leads to slightly higher returns because interest starts earning interest sooner. While the difference might seem small, it adds up over time, especially with larger balances and longer durations.
- Time Horizon (t): The longer your money is invested, the more significant the impact of compounding. The bank savings calculator demonstrates that consistent saving over extended periods yields exponential growth compared to shorter terms. Patience is key.
- Regular Contributions (PMT): Consistent, disciplined saving is crucial. The calculator shows how adding a fixed amount regularly significantly increases the total principal contributed and, consequently, the future value. Increasing this amount, even slightly, can accelerate wealth accumulation.
- Initial Deposit (P): While regular contributions are vital, a larger initial deposit provides a stronger foundation. It immediately starts earning interest, and that interest itself begins earning interest, giving your savings an early boost.
- Inflation: While not directly calculated in this tool, inflation erodes the purchasing power of your savings over time. A high interest rate helps to outpace inflation, preserving and growing your real wealth. Always consider the inflation rate when setting savings goals to ensure your money retains its value.
- Fees and Taxes: Savings accounts may have associated fees (e.g., monthly maintenance fees, withdrawal penalties) that can reduce your net returns. Additionally, interest earned is often taxable, which reduces the final amount you can keep. While this calculator focuses on gross growth, these factors should be considered in real-world financial planning.
Frequently Asked Questions (FAQ)
- Q1: What is the difference between simple interest and compound interest, and which does this calculator use?
- A1: Simple interest is calculated only on the principal amount. Compound interest is calculated on the principal amount plus any accumulated interest from previous periods. This bank savings calculator uses compound interest, as it’s standard for most savings accounts and demonstrates the true growth potential over time.
- Q2: Can I use this calculator for investment accounts like stocks or bonds?
- A2: This calculator is specifically designed for bank savings accounts with fixed interest rates and compounding. Investment accounts typically have variable returns and different risk profiles, requiring specialized calculators (like a stock market simulator or investment return calculator) for accurate projections.
- Q3: My bank offers daily compounding. How does that affect my savings compared to monthly?
- A3: Daily compounding generally yields slightly higher returns than monthly compounding because interest is calculated and added to the principal more frequently. The calculator allows you to select daily (365) compounding to see this effect.
- Q4: What if the interest rate changes over time?
- A4: This calculator assumes a fixed annual interest rate for the entire duration. In reality, interest rates fluctuate. For long-term projections with variable rates, you might need to recalculate periodically with updated rates or use more advanced financial planning tools.
- Q5: How accurate are the projections from this bank savings calculator?
- A5: The projections are mathematically accurate based on the inputs provided (fixed rate, consistent contributions). However, actual results can vary due to changes in interest rates, unforeseen fees, taxes, or changes in your contribution habits.
- Q6: What is the difference between ‘Total Principal Contributed’ and ‘Future Value’?
- A6: ‘Total Principal Contributed’ is the sum of all the money you put into the account (initial deposit + all regular contributions). ‘Future Value’ is the total amount you’ll have at the end, including both your contributions and all the interest earned.
- Q7: Can I input irregular contributions?
- A7: This specific calculator is set up for regular monthly contributions. For irregular savings amounts, you would need to manually adjust the total contributions and recalculate the interest earned, or use a spreadsheet program for more complex scenarios.
- Q8: Should I consider inflation when looking at the results?
- A8: Yes, absolutely. While the calculator shows the nominal future value, inflation reduces the purchasing power of that money. To understand your real return, you should compare the projected interest earned against the inflation rate over the same period. A positive real return means your savings are growing in value beyond just keeping pace with price increases.
Related Tools and Internal Resources
function validateInput(id, min, max, allowEmpty = false) {
var input = document.getElementById(id);
var value = parseFloat(input.value);
var errorElement = input.parentNode.querySelector(‘.error-message’);
var isValid = true;
if (!allowEmpty && (input.value === ” || isNaN(value))) {
errorElement.textContent = ‘This field is required.’;
isValid = false;
} else if (input.value !== ” && (isNaN(value) || (!allowEmpty && value max))) {
if (id === ‘initialDeposit’ && value === 0) {
errorElement.textContent = ‘Initial deposit must be a positive number.’;
isValid = false;
} else if (id === ‘monthlyContribution’ && value < 0) {
errorElement.textContent = 'Monthly contribution cannot be negative.';
isValid = false;
} else if (id === 'annualInterestRate' && (value 100)) {
errorElement.textContent = ‘Interest rate must be between 0% and 100%.’;
isValid = false;
} else if (id === ‘years’ && value 0) {
fvAnnuity = PMT * (Math.pow(1 + monthlyRate, numberOfPeriods) – 1) / monthlyRate;
} else {
// If rate is 0, future value is just the sum of contributions
fvAnnuity = PMT * numberOfPeriods;
}
// Total Future Value
var futureValue = fvInitial + fvAnnuity;
// Calculate Total Principal Contributed
var totalPrincipal = P + (PMT * 12 * t);
// Calculate Total Interest Earned
var totalInterest = futureValue – totalPrincipal;
// Format currency
var currencyFormatter = new Intl.NumberFormat(‘en-US’, {
style: ‘currency’,
currency: ‘USD’,
minimumFractionDigits: 2,
maximumFractionDigits: 2
});
document.getElementById(“totalPrincipal”).textContent = currencyFormatter.format(totalPrincipal);
document.getElementById(“totalInterest”).textContent = currencyFormatter.format(totalInterest);
document.getElementById(“futureValue”).textContent = currencyFormatter.format(futureValue);
document.getElementById(“result-summary”).textContent = “Your projected savings balance after ” + years + ” years will be ” + currencyFormatter.format(futureValue) + “.”;
document.getElementById(“result-summary”).classList.remove(‘hidden’);
// Populate Table and Chart Data
populateTableAndChart(P, PMT, r, n, t, numberOfPeriods, monthlyRate, futureValue);
}
function populateTableAndChart(P, PMT, r, n, t, numberOfPeriods, monthlyRate, futureValue) {
var tableBody = document.querySelector(“#savingsTable tbody”);
tableBody.innerHTML = ”; // Clear previous data
var savingsData = [];
var currentBalance = P;
var totalInterestAccrued = 0;
var totalContributionsAccrued = P; // Start with initial deposit
var yearlyChartData = {
labels: [],
principal: [],
interest: []
};
for (var year = 1; year <= t; year++) {
var beginningBalance = currentBalance;
var interestEarnedThisYear = 0;
var contributionsThisYear = PMT * 12;
for (var month = 0; month < 12; month++) {
var interestForMonth = currentBalance * monthlyRate;
interestEarnedThisYear += interestForMonth;
currentBalance += interestForMonth;
currentBalance += PMT;
totalContributionsAccrued += PMT;
}
currentBalance = parseFloat(currentBalance.toFixed(2)); // Ensure balance is rounded
interestEarnedThisYear = parseFloat(interestEarnedThisYear.toFixed(2));
var endingBalance = beginningBalance + contributionsThisYear + interestEarnedThisYear;
// Recalculate for precise year-end
var preciseEndingBalance = P * Math.pow(1 + r/n, n*year) + PMT * (12) * (Math.pow(1 + r/n, n*year) – 1) / (r/n);
preciseEndingBalance = parseFloat(preciseEndingBalance.toFixed(2));
var preciseTotalInterest = preciseEndingBalance – (P + (PMT * 12 * year));
yearlyChartData.labels.push(year);
yearlyChartData.principal.push(P + (PMT * 12 * year)); // Principal up to this year
yearlyChartData.interest.push(preciseTotalInterest); // Interest earned up to this year
var row = tableBody.insertRow();
var cellYear = row.insertCell();
var cellBeginBalance = row.insertCell();
var cellContributions = row.insertCell();
var cellInterest = row.insertCell();
var cellEndBalance = row.insertCell();
cellYear.textContent = year;
cellBeginBalance.textContent = currencyFormatter.format(beginningBalance);
cellContributions.textContent = currencyFormatter.format(contributionsThisYear);
cellInterest.textContent = currencyFormatter.format(interestEarnedThisYear);
cellEndBalance.textContent = currencyFormatter.format(preciseEndingBalance); // Use precise for table end balance
currentBalance = preciseEndingBalance; // Update for next year's beginning balance
}
// Update chart
updateSavingsChart(yearlyChartData);
}
function updateSavingsChart(data) {
var ctx = document.getElementById('savingsChart').getContext('2d');
// Destroy previous chart instance if it exists
if (window.mySavingsChart) {
window.mySavingsChart.destroy();
}
window.mySavingsChart = new Chart(ctx, {
type: 'line',
data: {
labels: data.labels,
datasets: [{
label: 'Total Principal',
data: data.principal,
borderColor: 'rgb(75, 192, 192)',
backgroundColor: 'rgba(75, 192, 192, 0.2)',
fill: false,
tension: 0.1
}, {
label: 'Total Interest Earned',
data: data.interest,
borderColor: 'rgb(255, 159, 64)',
backgroundColor: 'rgba(255, 159, 64, 0.2)',
fill: false,
tension: 0.1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Amount (USD)'
}
},
x: {
title: {
display: true,
text: 'Year'
}
}
},
plugins: {
tooltip: {
mode: 'index',
intersect: false,
},
title: {
display: true,
text: 'Savings Growth Over Time'
}
}
}
});
}
// Chart.js integration – requires Chart.js library to be included separately.
// Since external libraries are disallowed, we will use a placeholder for now.
// **NOTE: For a truly pure JS solution without libraries, SVG or Canvas would need direct drawing.**
// The following is a placeholder representing Chart.js functionality.
// In a real implementation, you'd include Chart.js via CDN or local file.
// Placeholder for Chart.js library – if not available, chart won't render.
// You would typically add: in the
// Mock Chart object if Chart.js is not loaded
if (typeof Chart === ‘undefined’) {
window.Chart = function() {
console.warn(“Chart.js library not loaded. Chart will not render.”);
return {
destroy: function() {}
};
};
// Mock context and chart instance
var canvas = document.getElementById(‘savingsChart’);
if (canvas) {
var ctx = canvas.getContext(‘2d’);
ctx.fillRect = function() {}; // Mock draw function
ctx.strokeRect = function() {}; // Mock draw function
ctx.beginPath = function() {}; // Mock draw function
ctx.moveTo = function() {}; // Mock draw function
ctx.lineTo = function() {}; // Mock draw function
ctx.stroke = function() {}; // Mock draw function
ctx.fill = function() {}; // Mock draw function
ctx.clearRect = function() {}; // Mock draw function
ctx.font = ’12px Arial’;
ctx.fillText = function(text, x, y) { console.log(‘fillText:’, text); };
}
}
function formatCurrency(amount) {
return ‘$’ + parseFloat(amount).toFixed(2);
}
function resetCalculator() {
document.getElementById(“initialDeposit”).value = “1000”;
document.getElementById(“monthlyContribution”).value = “100”;
document.getElementById(“annualInterestRate”).value = “4.5”;
document.getElementById(“years”).value = “10”;
document.getElementById(“compoundingFrequency”).value = “12”;
document.getElementById(“totalPrincipal”).textContent = “–“;
document.getElementById(“totalInterest”).textContent = “–“;
document.getElementById(“futureValue”).textContent = “–“;
document.getElementById(“result-summary”).classList.add(‘hidden’);
document.querySelector(“#savingsTable tbody”).innerHTML = ”;
if (window.mySavingsChart) {
window.mySavingsChart.destroy();
}
var ctx = document.getElementById(‘savingsChart’).getContext(‘2d’);
ctx.clearRect(0, 0, canvas.width, canvas.height); // Clear canvas
// Clear error states
var inputGroups = document.querySelectorAll(‘.input-group’);
inputGroups.forEach(function(group) {
group.classList.remove(‘error’);
var errorMsg = group.querySelector(‘.error-message’);
if(errorMsg) errorMsg.textContent = ”;
});
}
function copyResults() {
var summary = document.getElementById(“result-summary”).textContent;
var principal = document.getElementById(“totalPrincipal”).textContent;
var interest = document.getElementById(“totalInterest”).textContent;
var futureVal = document.getElementById(“futureValue”).textContent;
var tableHtml = “
Yearly Savings Breakdown
| Year | Beginning Balance | Contributions | Interest Earned | Ending Balance |
|---|---|---|---|---|
| ” + cell.textContent + “ |
“;
var chartExplanation = “\nChart shows the growth of your savings over time.”;
var textToCopy = `— Savings Projection Summary —\n${summary}\n\nTotal Principal Contributed: ${principal}\nTotal Interest Earned: ${interest}\n\n${tableHtml}\n${chartExplanation}\n—————————–`;
navigator.clipboard.writeText(textToCopy).then(function() {
var copyButton = document.querySelector(‘.btn-copy’);
var originalText = copyButton.textContent;
copyButton.textContent = ‘Copied!’;
setTimeout(function() {
copyButton.textContent = originalText;
}, 2000);
}).catch(function(err) {
console.error(‘Failed to copy text: ‘, err);
alert(‘Failed to copy results. Please copy manually.’);
});
}
// Initial calculation on page load
document.addEventListener(‘DOMContentLoaded’, function() {
calculateSavings();
// Initial chart update placeholder
var canvas = document.getElementById(‘savingsChart’);
var ctx = canvas.getContext(‘2d’);
ctx.fillStyle = ‘#e9ecef’;
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.fillStyle = ‘#6c757d’;
ctx.font = ’16px sans-serif’;
ctx.textAlign = ‘center’;
ctx.fillText(‘Chart data will appear after calculation.’, canvas.width / 2, canvas.height / 2);
});