The Degradation Rate Calculator is an essential tool for engineers, scientists, and asset managers who need to quantify the loss of performance, capacity, or value over time. Whether you are analyzing lithium-ion battery health (SOH), solar panel efficiency loss, or material wear in mechanical systems, knowing the specific rate of decay allows for better predictive maintenance and lifecycle planning.
What is Degradation Rate?
Degradation rate refers to the speed at which an asset or system loses its original functionality or capacity. It is typically expressed as a percentage loss per unit of time (e.g., 1.5% per year) or per usage cycle (e.g., 0.05% per charge cycle).
For example, a standard solar panel might degrade at a rate of 0.5% per year, meaning after 20 years, it will operate at roughly 90% of its original efficiency. Similarly, an electric vehicle battery degrades based on both calendar aging (time) and cycle aging (usage).
How to Calculate Degradation
To calculate the degradation rate, you need the initial baseline value, the current measured value, and the duration between these two measurements. The core formulas used in this calculator are:
Absolute Loss:Initial Value – Current Value
Total Degradation (%):(Absolute Loss / Initial Value) × 100
Tracking degradation is critical in several industries:
Energy Storage: Monitoring State of Health (SOH) in batteries to prevent unexpected failure.
Photovoltaics: Ensuring solar arrays meet warranty standards for power output over 25+ years.
Manufacturing: Assessing tool wear rates to schedule replacements before product quality suffers.
Chemistry & Biology: calculating the decay of chemical concentration or biological activity over time.
Factors Influencing Degradation
The rate of degradation is rarely constant and can be influenced by environmental stressors. High temperatures generally accelerate chemical degradation in batteries. Mechanical stress and friction accelerate wear in physical components. By calculating the rate periodically, you can determine if external factors are shortening the lifespan of your equipment faster than anticipated.
function calculateDegradation() {
// 1. Get input values
var initial = document.getElementById('initialCapacity').value;
var current = document.getElementById('currentCapacity').value;
var duration = document.getElementById('timeDuration').value;
var unitName = document.getElementById('unitLabel').value;
// Elements for output
var errBox = document.getElementById('errorMessage');
var resultBox = document.getElementById('results');
var elAbsLoss = document.getElementById('resAbsLoss');
var elTotalPct = document.getElementById('resTotalPct');
var elRate = document.getElementById('resRate');
var elRemaining = document.getElementById('resRemaining');
var elUnit = document.getElementById('resUnit');
// 2. Clear previous errors and results
errBox.style.display = 'none';
resultBox.style.display = 'none';
errBox.innerHTML = ";
// 3. Validation
if (initial === " || current === " || duration === ") {
errBox.innerHTML = 'Please fill in all numeric fields.';
errBox.style.display = 'block';
return;
}
var initVal = parseFloat(initial);
var currVal = parseFloat(current);
var timeVal = parseFloat(duration);
if (isNaN(initVal) || isNaN(currVal) || isNaN(timeVal)) {
errBox.innerHTML = 'Please enter valid numbers.';
errBox.style.display = 'block';
return;
}
if (timeVal initial (negative degradation / growth)
if (loss < 0) {
elTotalPct.innerHTML = Math.abs(pctLoss).toFixed(2) + '% (Improvement)';
elRate.innerHTML = Math.abs(rate).toFixed(3) + '% / ' + unitName;
} else {
elTotalPct.innerHTML = pctLoss.toFixed(2) + '%';
elRate.innerHTML = rate.toFixed(3) + '% / ' + unitName;
}
elRemaining.innerHTML = remainingPct.toFixed(2) + '%';
elUnit.innerHTML = unitName;
// Show results
resultBox.style.display = 'block';
}