Retention and Attrition Rate Calculation

Employee Retention & Attrition Calculator

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Retention Rate

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Attrition Rate

function calculateHRMetrics() { var start = parseFloat(document.getElementById('startEmps').value); var end = parseFloat(document.getElementById('endEmps').value); var hires = parseFloat(document.getElementById('newHires').value); var left = parseFloat(document.getElementById('leftEmps').value); if (isNaN(start) || isNaN(end) || isNaN(hires) || isNaN(left)) { alert("Please enter valid numbers for all fields."); return; } if (start <= 0) { alert("Starting employee count must be greater than zero."); return; } // Calculation Logic // Retention Rate = ((End – New Hires) / Start) * 100 var retention = ((end – hires) / start) * 100; // Average Employees = (Start + End) / 2 var avgEmps = (start + end) / 2; // Attrition Rate = (Left / Average) * 100 var attrition = (left / avgEmps) * 100; // Result Display document.getElementById('resultsArea').style.display = 'block'; document.getElementById('retentionVal').innerText = retention.toFixed(2) + '%'; document.getElementById('attritionVal').innerText = attrition.toFixed(2) + '%'; var summary = "During this period, your organization started with " + start + " employees and ended with " + end + ". "; summary += "With " + hires + " new hires and " + left + " departures, your net growth was " + (end – start) + " employees."; document.getElementById('metricSummary').innerText = summary; }

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How to Calculate Retention and Attrition Rates

In human resources and talent management, understanding the difference between retention and attrition is critical for workforce planning. These two metrics provide a snapshot of your organizational health, employee satisfaction, and operational stability.

What is Retention Rate?

The Retention Rate measures the percentage of employees who stayed with the company throughout a specific period. It intentionally excludes new hires to focus purely on the "staying power" of your existing workforce. A high retention rate typically suggests a positive company culture and competitive compensation.

Retention Rate Formula:
((Number of Employees at End of Period – New Hires During Period) / Number of Employees at Start of Period) x 100

What is Attrition Rate?

The Attrition Rate (often used interchangeably with turnover rate) calculates the frequency at which employees leave the organization. Unlike retention, it is usually calculated against the average number of employees during the period to account for fluctuations in headcount.

Attrition Rate Formula:
(Employees Who Left During Period / Average Number of Employees) x 100

A Realistic Example

Let's look at a mid-sized tech company over a one-year period:

• Start of Year: 200 Employees
• End of Year: 220 Employees
• New Hires: 50 Employees
• Departures (Left): 30 Employees

Calculating Retention:
((220 – 50) / 200) * 100 = 85% Retention Rate
This means 85% of the original staff stayed with the company.

Calculating Attrition:
Average headcount: (200 + 220) / 2 = 210
(30 / 210) * 100 = 14.28% Attrition Rate

Why These Metrics Matter

By tracking these numbers monthly or quarterly, HR departments can identify trends. If the attrition rate spikes, it may indicate a management issue or a competitor offering better terms. Conversely, a stable retention rate ensures that institutional knowledge is preserved, reducing training costs and maintaining productivity levels.