What Is Retention Rate?
Retention rate is the percentage of employees who remain with an organisation over a defined period — typically one year — calculated as (employees at end of period minus new hires) divided by employees at start of period. The inverse of turnover rate, retention rate is a leading indicator of workforce stability and employer brand health. According to SHRM, the average cost of replacing an employee is 6-9 months of their salary, making a 5-point improvement in retention rate highly material for staffing economics.
TL;DR
Retention rate measures the percentage of employees who stay with an organisation over a defined period, typically a year. It is the inverse of turnover rate and a direct indicator of how well the organisation holds onto the talent it acquires. High retention signals that people find enough reason to stay; low retention signals the opposite.
What Retention Rate Actually Measures
Retention rate is a lagging indicator of everything that happened to employees before the measurement period ended. The formula is simple: divide the number of employees who stayed for the full period by the number employed at the start, then multiply by 100.
A 90% annual retention rate means nine out of ten employees who were on the payroll at the start of the year were still there twelve months later. That one departure could be a voluntary resignation, a performance exit, or a redundancy -- the headline number does not distinguish. Segmenting retention by departure type is where the real insight lives.
Retention is also most useful when measured by cohort. Overall company retention conceals the fact that your engineering team might be at 95% while your sales development function is at 60%. Aggregated numbers are useful for board reporting. Segmented numbers are useful for actually doing something about the problem.
Why It Matters for Recruitment
Retention rate is the ultimate measure of hiring quality. Sourcing the right candidates, writing compelling job posts, and running a slick interview process all mean very little if the people you hire leave within a year.
For recruiters, retention data closes the loop. If candidates hired from a particular source have a 12-month retention rate of 55% while those from another source are at 88%, that sourcing decision is worth revisiting regardless of cost-per-hire. If candidates who passed through one interviewer consistently leave within six months, that is information worth having.
Retention also has direct cost implications for recruitment. The commonly cited cost of replacing an employee ranges from half to twice their annual salary, factoring in sourcing costs, lost productivity during the vacancy, onboarding time, and ramp-up. A team with 70% retention is constantly in a state of replacement hiring. The recruitment function becomes a treadmill rather than a growth engine.
In Practice
A 200-person retail technology company tracks 12-month retention by department and hiring source. They find that overall retention sits at 82%, which looks acceptable on its surface. When they segment by department, customer success comes in at 68%, well below the company average. When they cross-reference by hiring source, they find that candidates sourced through two specific job boards have 12-month retention of 61%, while referrals and LinkedIn direct outreach retain at 89% and 85% respectively.
Armed with this data, the recruiting team reduces spend on the underperforming job boards, invests more in referral programme incentives for customer success roles, and flags the issue to the customer success leadership team for an onboarding review. Six months later, 12-month projected retention in that department is trending up.
Key Facts
| Concept | Definition | Practical Implication |
|---|---|---|
| Retention rate formula | (Employees at end of period / Employees at start) x 100 | Always specify the period -- annual is standard but 90-day retention is also tracked |
| Voluntary vs. involuntary retention | Separates resignations from performance exits and redundancies | Voluntary retention is the more actionable signal for culture and management quality |
| Cohort retention | Retention tracked for a specific group (hire year, department, source) | Reveals where attrition is concentrated rather than masking it in averages |
| Cost of attrition | Estimated replacement cost per departed employee | Quantifies the financial return on retention improvement investments |
| First-year retention | Retention measured at 12 months from hire date | Directly reflects hiring quality and onboarding effectiveness |
| Retention by source | Comparing retention rates across sourcing channels | Enables data-driven sourcing budget allocation |
| Benchmark comparison | Industry or role-type average retention | Contextualises whether your rate is a company problem or a sector norm |
Key Statistics
LinkedIn's Workforce Report benchmarks strong retention in professional roles at 85% or above annually; organisations below 75% face compounding disruption to team performance and institutional knowledge.
LinkedIn Workforce Report, 2023