Calculate how fast you are using inventory, fuel, or materials.
Days
Weeks
Months
Hours
Please check your inputs. Initial quantity cannot be less than current quantity, and time cannot be zero.
Total Consumed:–
Consumption Rate:–
Est. Time Remaining:–
Projected Stockout:–
Understanding Consumption Rate
Whether you are managing warehouse inventory, tracking raw material usage in manufacturing, or monitoring fuel efficiency, understanding your Consumption Rate is vital for operational efficiency. This metric defines the speed at which a resource is depleted over a specific period.
Formula:
Consumption Rate = (Initial Quantity – Current Quantity) / Time Elapsed
Why Calculate Consumption Rate?
Accurate consumption tracking prevents both stockouts (running out of materials) and overstocking (tying up capital). By knowing your specific burn rate, you can:
Optimize Reordering: precise knowledge of daily or weekly usage helps set accurate reorder points.
Forecast Demand: Identify seasonal trends where consumption spikes or drops.
Reduce Waste: In perishable goods scenarios, matching consumption to procurement reduces spoilage.
Calculate Runway: Know exactly how many days of operation you have left before you need to replenish.
How to Use This Calculator
This tool is designed to be unit-agnostic. You can use it for:
Inventory: Units, boxes, pallets.
Manufacturing: Kilograms of raw material, liters of chemicals.
Total Consumed: The absolute amount of resource used during the measured period.
Consumption Rate: The average usage per single unit of time (e.g., per day or per hour).
Est. Time Remaining (Runway): Based on your current rate, this is how long your remaining stock will last. If your consumption fluctuates heavily, consider adding a safety margin to this number.
function calculateConsumption() {
// 1. Get DOM elements
var initialQtyInput = document.getElementById('initialQty');
var currentQtyInput = document.getElementById('currentQty');
var timePeriodInput = document.getElementById('timePeriod');
var timeUnitSelect = document.getElementById('timeUnit');
var errorMsg = document.getElementById('errorMsg');
var resultsDiv = document.getElementById('results');
// 2. Parse values
var initial = parseFloat(initialQtyInput.value);
var current = parseFloat(currentQtyInput.value);
var time = parseFloat(timePeriodInput.value);
var unit = timeUnitSelect.value;
var unitLabel = unit.replace('s', "); // Remove plural for singular display
// 3. Reset error state
errorMsg.style.display = 'none';
resultsDiv.style.display = 'none';
// 4. Validation
if (isNaN(initial) || isNaN(current) || isNaN(time)) {
errorMsg.innerText = "Please enter valid numbers for all fields.";
errorMsg.style.display = 'block';
return;
}
if (time initial) {
errorMsg.innerText = "Current quantity cannot be higher than Initial quantity (unless restocking occurred, which this calculator does not account for).";
errorMsg.style.display = 'block';
return;
}
// 5. Calculation Logic
var consumed = initial – current;
var rate = consumed / time;
var runway = 0;
if (rate > 0) {
runway = current / rate;
} else {
runway = Infinity; // Or handle as "No consumption"
}
// 6. Formatting Output
document.getElementById('resConsumed').innerHTML = consumed.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 2}) + " Units";
document.getElementById('resRate').innerHTML = rate.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) + " / " + unitLabel;
if (rate === 0) {
document.getElementById('resRemaining').innerHTML = "Indefinite (No usage)";
document.getElementById('resStockout').innerHTML = "Never";
} else {
document.getElementById('resRemaining').innerHTML = runway.toLocaleString(undefined, {minimumFractionDigits: 1, maximumFractionDigits: 1}) + " " + unit;
// Calculate projected date (only valid if unit is days, roughly)
// For simplicity in a generic calc, we display the count.
// However, let's try to give a nice text representation.
document.getElementById('resStockout').innerHTML = "In " + runway.toFixed(1) + " " + unit;
}
// 7. Show Results
resultsDiv.style.display = 'block';
}