Deposit Decay Rate Calculator
.ddr-calc-container {
max-width: 800px;
margin: 20px auto;
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background: #ffffff;
border: 1px solid #e2e8f0;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
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.ddr-calc-header {
background: #2c3e50;
color: white;
padding: 20px;
text-align: center;
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.ddr-calc-header h2 {
margin: 0;
font-size: 1.5rem;
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.ddr-calc-body {
padding: 30px;
display: flex;
flex-wrap: wrap;
gap: 30px;
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.ddr-input-section {
flex: 1;
min-width: 300px;
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.ddr-result-section {
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display: block;
margin-bottom: 8px;
font-weight: 600;
color: #4a5568;
font-size: 0.95rem;
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.ddr-input-wrapper {
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.ddr-form-control {
width: 100%;
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transition: border-color 0.2s;
box-sizing: border-box;
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.ddr-form-control:focus {
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.ddr-result-value {
font-weight: 700;
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margin-top: 5px;
display: none;
}
Remaining Value
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Total Amount Lost:
—
Percentage Retained:
—
Effective Half-Life:
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Understanding Deposit Decay
In finance, economics, and certain physical systems, "Deposit Decay" refers to the gradual reduction in the value or quantity of a held asset over time. This calculator helps you determine the future value of a deposit that is subject to a constant negative rate, such as inflation, storage fees, or natural degradation.
How the Calculation Works
This tool utilizes the exponential decay formula (or compound reduction formula) to project future values. Unlike compound interest which grows wealth, decay rates erode it. The core formula used is:
V = P × (1 – r)t
- V: The remaining value or quantity after time t.
- P: The initial principal deposit or quantity.
- r: The decay rate expressed as a decimal (e.g., 5% = 0.05).
- t: The number of time periods elapsed.
Real-World Applications
Calculating deposit decay is critical in several scenarios:
- Inflation Analysis: A $10,000 cash deposit earning 0% interest decays in purchasing power if inflation is 3%.
- Asset Depreciation: Physical machinery or vehicles often decay in value at a predictable yearly percentage.
- Tokenomics: Certain cryptocurrency protocols implement "decay" or "demurrage" where tokens held in a wallet slowly burn or decrease to encourage circulation.
- Resource Depletion: Estimating the remaining reserves of a natural resource deposit under constant extraction rates.
Example Calculation
Imagine you have a Initial Deposit of 50,000 units. The system imposes a Decay Rate of 8% per year. You want to know what will remain after 5 years.
Using the calculator:
- Initial: 50,000
- Rate: 8% (0.08)
- Time: 5 years
- Result: 50,000 × (1 – 0.08)5 = 50,000 × 0.659 = 32,954.56
In this scenario, over 17,000 units (approx 34%) are lost solely due to the decay factor.
function calculateDecay() {
// Get Input Values
var initialInput = document.getElementById('initialDeposit');
var rateInput = document.getElementById('decayRate');
var timeInput = document.getElementById('duration');
var P = parseFloat(initialInput.value);
var r = parseFloat(rateInput.value);
var t = parseFloat(timeInput.value);
// Reset Styles
rateInput.style.borderColor = "#cbd5e0";
document.getElementById('rateError').style.display = "none";
// Validation
if (isNaN(P) || isNaN(r) || isNaN(t)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (r 100) {
rateInput.style.borderColor = "#e53e3e";
document.getElementById('rateError').style.display = "block";
return;
}
// Logic: V = P * (1 – r/100)^t
var rateDecimal = r / 100;
var remainingValue = P * Math.pow((1 – rateDecimal), t);
var totalLost = P – remainingValue;
var percentRetained = (remainingValue / P) * 100;
// Half-Life Logic: t_half = ln(0.5) / ln(1 – r)
// Check for 0 rate to avoid division by zero
var halfLifeText = "Infinite";
if (r > 0) {
var halfLife = Math.log(0.5) / Math.log(1 – rateDecimal);
halfLifeText = halfLife.toFixed(2) + " Periods";
} else if (r === 100) {
halfLifeText = "Immediate";
}
// Formatting Output
// Helper function for comma separation
function formatNumber(num) {
return num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}
// Display Results
document.getElementById('finalResult').innerHTML = formatNumber(remainingValue);
document.getElementById('totalLost').innerHTML = formatNumber(totalLost);
document.getElementById('percentRetained').innerHTML = percentRetained.toFixed(2) + "%";
document.getElementById('halfLife').innerHTML = halfLifeText;
}