Retention rate measures the percentage of people (employees, customers, or users) who stay with you over a specific time period. The basic formula is the same across contexts: take the number who remained at the end of a period, divide by the number you started with, and multiply by 100. The details shift depending on whether you’re tracking employees on payroll, subscribers renewing a plan, or app users coming back each month.
The Basic Retention Rate Formula
The core calculation works like this:
Retention Rate = (Starting Count − Number Who Left) / Starting Count × 100
Say you start a quarter with 200 employees and 12 leave during that quarter. Your retention rate is (200 − 12) / 200 × 100 = 94%. If you’re tracking customers instead of employees, the math is identical: swap “employees” for “customers” and plug in your numbers.
The number you get is a percentage that tells you how well you’re holding onto people. A 94% quarterly retention rate means you kept nearly everyone. A 60% rate means you lost four out of every ten.
Employee Retention Rate
HR teams typically calculate retention over a set period: monthly, quarterly, or annually. You need two numbers: total workforce headcount at the start of the period and the number of employees who left during it. Voluntary resignations, terminations, and retirements all count as departures.
One important detail: retention rate and turnover rate are inverses. If your turnover rate for the year is 3%, your retention rate is 97%. You don’t need to calculate both separately. Knowing one gives you the other instantly.
Where it gets tricky is deciding who counts in your starting headcount. Most companies include all active employees on the first day of the measurement period. New hires who joined mid-period are typically excluded from the starting count, since they weren’t part of the group you’re measuring. If you include them, you inflate your denominator and make retention look artificially better than it is.
Customer Retention Rate
Customer retention rate tells you what share of your existing customers stuck around over a given period. The formula adds one adjustment to account for new customers acquired during the period:
Customer Retention Rate = (Customers at End of Period − New Customers Acquired) / Customers at Start of Period × 100
Suppose you start January with 500 customers, gain 80 new ones, and end the month with 510 total. Your retention rate is (510 − 80) / 500 × 100 = 86%. That means you lost 70 of your original 500 customers, keeping 430 of them.
Stripping out new customers is essential. Without that step, strong acquisition could mask a serious retention problem. You’d see total customer counts climbing while your existing base quietly erodes.
Benchmarks vary dramatically by industry. Professional services companies average around 84% customer retention, software companies around 77%, and banking around 75%. Ecommerce sits far lower at roughly 30%, largely because online shoppers have little switching cost and may buy from a store only once. These numbers give you a baseline, but the most useful comparison is always your own rate over time.
Cohort Retention Analysis
Cohort retention goes a level deeper by grouping people based on when they started, then tracking each group separately over time. This is especially common in SaaS, mobile apps, and subscription businesses where you want to see how engagement changes as users age.
A cohort is simply a group that shares a starting point. “Users who signed up in January” is a cohort. “Customers who made their first purchase in March” is another. The process has a few clear steps:
- Define the cohort. Pick the shared characteristic and the time window. Usually this is signup date or first purchase date.
- Choose your time buckets. Decide whether you’re measuring retention weekly, monthly, or at some other interval.
- Count who returns in each bucket. For each time period after the starting point, count how many members of the original cohort are still active.
- Convert to percentages. Divide the number of returning users by the original cohort size and multiply by 100.
Here’s a concrete example. Say 1,000 users sign up in January. In February, 600 of them are still active. That’s 60% retention for Month 1. In March, 400 of the original 1,000 are active. That’s 40% retention for Month 2. You always divide by the original cohort size (1,000), not by the previous month’s number.
The power of cohort analysis is that it lets you compare groups side by side. If your January cohort retained 60% after one month but your April cohort retained 72%, something you changed between January and April is working. Without cohort tracking, those improvements get buried in your aggregate numbers.
Choosing the Right Time Period
The period you measure over changes what the number means. A 95% monthly employee retention rate sounds excellent, but annualized it compounds to roughly 54%, meaning you’d lose nearly half your staff in a year. Short measurement windows make retention look better because there’s less time for people to leave.
Match the time period to how your business actually operates. Subscription businesses with monthly billing often track monthly retention. Companies with annual contracts care most about yearly renewal rates. For employee retention, annual measurement is the most common standard because it smooths out seasonal hiring and departure patterns.
Whatever period you choose, keep it consistent. Comparing a monthly rate to a quarterly rate is meaningless. Pick a cadence and stick with it so your trend line tells a real story.
What Your Retention Rate Actually Tells You
A single retention number is a snapshot. It becomes useful when you track it over time, break it down by segment, or compare it against your own historical performance. A SaaS company with 92% monthly retention is in a very different position than one at 85%, even though the gap looks small. Over 12 months, that 92% compounds to about 38% of users still around, while 85% drops to roughly 14%.
Segment-level retention is often more revealing than the company-wide number. Your overall rate might be steady at 80%, but when you split by customer size, you might find enterprise clients retain at 95% while small accounts churn at 50%. That changes where you focus your effort.
For employee retention, breaking the number down by department, tenure, or role level highlights where problems actually live. A company-wide 90% retention rate can hide the fact that engineering is at 75% while operations is at 98%. The aggregate number gives you a headline. The segmented numbers tell you where to act.