Accounting Retention Rate Formula
Learn how to calculate an accounting practice's monthly client retention rate, churn rate, retained clients, and net client change.
Monthly client retention measures the share of clients active at the beginning of a month who remain active at month end. Removing clients acquired during the month prevents new business from making existing-client retention appear stronger than it is.
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Monthly Client Retention Rate
Where:
Subtract newly acquired clients from the month-end total to estimate how many opening clients remained. Divide that number by the opening client count and multiply by 100.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| startingClients - Clients at Start of Month | The number of active clients at the beginning of the reporting month. | clients |
| endingClients - Clients at End of Month | The total number of active clients at month end, including clients gained during the month. | clients |
| newClients - New Clients Gained During Month | Clients who first became active during the reporting month. | clients |
| retainedClients - Retained Clients | The estimated number of beginning-of-month clients who remained active at month end. | clients |
| monthlyRetentionRate - Monthly Retention Rate | The percentage of opening clients retained through the month. | percent |
Step-by-Step Calculation
Record the opening client base
Use the count of active clients on the first day of the month.
startingClients
Remove newly acquired clients
This separates clients retained from the opening base from clients added during the month.
retainedClients = endingClients - newClients
Calculate the retention ratio
Divide retained opening clients by the number of clients present at the start.
retentionRatio = retainedClients / startingClients
Convert the ratio to a percentage
Multiply the ratio by 100 to express monthly retention as a percentage.
monthlyRetentionRate = retentionRatio * 100
Calculate churn for context
Churn is the percentage of opening clients who did not remain active at month end.
monthlyChurnRate = 100 - monthlyRetentionRate
Calculate overall client movement
Net client change shows whether the total active client count increased or decreased, regardless of retention.
netClientChange = endingClients - startingClients
Example: 100-client accounting practice
Find retained clients
98 − 5
93 clients
Calculate retention
(93 ÷ 100) × 100
93.0%
Calculate churn
100 − 93.0
7.0%
Calculate net client change
98 − 100
−2 clients
Final Result
The estimated monthly client retention rate is 93.0%, with 93 retained clients, 7.0% churn, and a net decrease of 2 active clients.
Assumptions
- ✓A retained client was active at both the beginning and the end of the same calendar month.
- ✓New clients are excluded from retained clients, including only clients first becoming active during the month.
- ✓Each active client is counted once, regardless of fees, services, or revenue generated.
- ✓Client status is recorded consistently at both month-end dates.
Limitations
- !The calculation measures client counts, not client value; losing one high-fee client has the same effect as losing one low-fee client.
- !Pauses, seasonal engagements, mergers, and reactivated clients can affect results depending on the practice's status definitions.
- !A monthly result can fluctuate because of billing cycles or short-term client activity.
- !The formula does not identify why clients left or whether departures were voluntary.
Common Mistakes to Avoid
Using the total month-end client count as retained clients without subtracting new clients.
Counting a reactivated former client as a new client when the reporting policy treats that client differently.
Changing the definition of active client between the start and end of the month.
Comparing months with different reporting cut-off dates or incomplete client records.
Treating net client growth as the same metric as client retention.
Related Formulas
Frequently Asked Questions
What is the formula for monthly accounting client retention rate?
The formula is ((ending clients − new clients) ÷ starting clients) × 100.
How do I calculate retained clients?
Subtract clients gained during the month from the total active clients at the end of the month.
Why are new clients subtracted from ending clients?
They are subtracted so the calculation measures how many clients from the opening base remained, rather than overall growth.
What is the monthly churn formula?
Monthly churn rate equals 100 minus the monthly retention rate.
Can monthly retention exceed 100%?
Under consistent use of this formula, it normally should not. A result above 100% may indicate that new, returning, or transferred clients were classified inconsistently.
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