function calculateConsumption() {
var initial = parseFloat(document.getElementById('initialQuantity').value);
var remaining = parseFloat(document.getElementById('remainingQuantity').value);
var time = parseFloat(document.getElementById('timeElapsed').value);
var unit = document.getElementById('timeUnit').value;
var costPerUnit = parseFloat(document.getElementById('unitCost').value);
var resultsDiv = document.getElementById('consumptionResults');
if (isNaN(initial) || isNaN(remaining) || isNaN(time) || time initial) {
alert("Remaining quantity cannot be greater than initial quantity.");
return;
}
var totalUsed = initial – remaining;
var rate = totalUsed / time;
var timeToEmpty = remaining / rate;
resultsDiv.style.display = 'block';
document.getElementById('rateOutput').innerHTML = "Consumption Rate: " + rate.toFixed(2) + " units per " + unit.slice(0, -1).toLowerCase();
document.getElementById('totalUsedOutput').innerHTML = "Total Quantity Consumed: " + totalUsed.toFixed(2) + " units";
if (rate > 0) {
document.getElementById('depletionOutput').innerHTML = "Estimated Time Until Depleted: " + timeToEmpty.toFixed(2) + " " + unit.toLowerCase();
} else {
document.getElementById('depletionOutput').innerHTML = "Estimated Time Until Depleted: N/A (No consumption detected)";
}
if (!isNaN(costPerUnit)) {
var totalCost = totalUsed * costPerUnit;
var costPerTime = rate * costPerUnit;
document.getElementById('costOutput').innerHTML = "Financial Analysis: Total cost of " + totalUsed.toFixed(2) + " units is $" + totalCost.toFixed(2) + " (approx. $" + costPerTime.toFixed(2) + " per " + unit.slice(0, -1).toLowerCase() + ")";
} else {
document.getElementById('costOutput').innerHTML = "";
}
}
Understanding the Rate of Consumption
The rate of consumption is a critical metric used across various industries, from manufacturing and logistics to personal finance and environmental science. It measures the speed at which a resource—whether it be fuel, raw materials, electricity, or inventory—is being utilized over a specific period of time.
How to Calculate Consumption Rate
The basic formula for calculating the rate of consumption is simple but powerful:
Rate = (Initial Quantity – Remaining Quantity) / Time Elapsed
Key Real-World Applications
Business Inventory: Retailers track how quickly stock leaves the shelf to determine when to reorder (Lead Time Analysis).
Environmental Science: Calculating water usage in a drought-prone area to predict how long a reservoir will last.
Fuel Efficiency: Fleet managers monitor liters per hour or miles per gallon to optimize routes and identify mechanical issues.
Project Management: "Burn Rate" in startups measures how fast venture capital is being spent before the company reaches profitability.
Practical Example
Imagine a manufacturing plant starts the week with 1,000 kg of raw plastic resin. After 4 days of production, an inventory check shows 200 kg remaining.
Total Consumed: 1,000 kg – 200 kg = 800 kg.
Daily Rate: 800 kg / 4 days = 200 kg per day.
Time to Empty: 200 kg remaining / 200 kg per day = 1 day left.
Using this data, the manager knows they must receive a new shipment within 24 hours to avoid a production shutdown.
Why Track Consumption?
Monitoring these rates allows for Predictive Maintenance and Budget Forecasting. By knowing your average usage, you can avoid emergency shortages, reduce waste by identifying abnormal spikes in consumption, and negotiate better pricing with suppliers based on predictable volume needs.