The percentage of customers who were active at the start of a period but discontinued by the end; it is the inverse of retention. In contractual/subscription settings, churn is defined relative to the prior period’s active base.

How do I calculate churn using Start/End/New?

Use churned = Start + New − End, then churn_rate = churned / Start. Retention_rate = 1 − churn_rate. This follows from the standard retention formula Retention = (End − New) / Start.

What if I already know how many customers churned?

Divide by the starting customers: churn_rate = Churned / Start. Retention_rate = 1 − churn_rate.

Which period should I pick—monthly, quarterly, or annually?

Any is fine; stay consistent. When comparing periods, convert via compounding (see next FAQ) rather than multiplying/dividing by 12 or 3.

How do I convert monthly churn to annual churn (and back)?

annual_churn = 1 − (1 − monthly_churn)^12. monthly_churn = 1 − (1 − annual_churn)^(1/12). Assumes a constant per-month hazard within the year.

How is retention rate computed here?

Retention_rate = (End − New) / Start, and Retention_rate = 1 − Churn_rate.

Can you show a worked example with the inputs in the screenshot?

Start = 1000, New = 50, End = 950 → Churned = 1000 + 50 − 950 = 100; Churn = 100 / 1000 = 0.10 = 10%; Retention = 90%.

What’s the difference between customer churn and revenue churn?

Customer churn counts lost customers; revenue churn measures lost recurring revenue from existing customers (usually start-of-period MRR lost net of upgrades). Use each for different questions.

Which denominator should I use? Start, average, or end?

The standard in subscription (“contractual”) settings is start-of-period customers, aligning with definitions of retention/churn as transitions from last period’s active base. Some practitioners use an average-of-period base, but it mixes acquisition dynamics into the rate.

What if End > Start + New (i.e., the identity implies negative churn)?

Negative churn is not interpretable for headcount churn; re-check inputs. Reactivations/returning customers should be counted in “New,” and data anomalies should be corrected so churned = max(0, Start + New − End).

How many decimals should I show, and what is “churn (decimal)”?

Percent is typical; decimals are the 0–1 form (e.g., 0.10). For reporting, two decimals are customary unless your audience needs more precision.

How is churn linked to customer lifetime?

With an approximately constant per-period churn, expected customer lifetime in periods ≈ 1 / churn_rate (e.g., 2% monthly churn → ~50 months).

Any tips to replicate this in a spreadsheet?

Put Start in A2, New in B2, End in C2. Churned in D2: =A2+B2−C2. Churn % in E2: =IF(A2>0,D2/A2,""). Retention % in F2: =1−E2. Annualize from monthly in G2: =1−(1−E2)^12.

Why does retention matter so much economically?

Higher retention is strongly associated with profitability in services and subscriptions; classic research shows small retention gains can yield large profit lifts. Use churn/retention as core operating KPIs.

Churn Rate Calculator - Customer & SaaS Retention

Churn Rate Calculator

Calculate customer churn and retention using either direct start/end/new inputs or a simple churned-count method.

Method

Provide starting customers, new customers acquired, and ending customers. Churned = Start + New − End.

Period

Classifications use monthly thresholds.

Start customers

New customers

End customers

Churned customers

Results

Churn %
Retention %
Churn (decimal)
Churned customers
Start customers
End customers
New customers
Churn level

Compute churn rate, retention, and churned customers for SaaS and subscription businesses. Enter start, end, and new customers or a direct churned count—get instant, precise outputs.

Formula

Method: Start/End/New

churned = start + new − end

churn_rate = churned / start

retention = 1 − churn_rate

Method: Churned Count

churn_rate = churned / start

retention = 1 − churn_rate

Monthly → Annualized (approx.)

annualized_churn = 1 − (1 − monthly_churn) ^ 12

Examples

Start customers = 1000; New customers = 50; End customers = 950

churned = 100; churn_rate = 100 / 1000 = 0.1 = 10%; retention = 90%; churn (decimal) = 0.1

Features

Two methods: Start/End/New or Churned Count.
Period selector: Monthly, Quarterly, Annually (classification uses monthly thresholds).
Inputs: Start customers, New customers, End customers (or Start + Churned).
Outputs: Churn %, Retention %, Churn (decimal), Churned customers, Start, End, New, Churn level.
Show decimals toggle for percentage precision.
Clear number formatting with thousands separators.

How to Use the Churn Rate Calculator

Follow these steps to calculate churn and retention from your customer counts. Works for SaaS churn or subscription retention tracking.

Choose the method
Select “Start/End/New” if you know customers at the start and end of the period plus how many new customers you added. Pick “Churned Count” if you directly track how many customers churned. Using the wrong method will misclassify inputs and skew results.
Select the period
Pick Monthly, Quarterly, or Annually to match your reporting window. The math is identical; labels and thresholds adjust to the period you choose. Avoid mixing counts from different periods.
Enter start customers
Type the number of active, paying customers at the beginning of the period (e.g., 1000). Use whole numbers without commas (enter 1000, not 1,000). Do not include free trials or paused accounts unless your policy counts them as “active.”
Enter new customers
Input how many new paying customers you acquired during the period (e.g., 50). Source this from your CRM/billing system for the same period. Don’t include upgrades from existing customers; only net-new accounts.
Enter end customers or churned
For “Start/End/New,” enter the paying customers at period end (e.g., 950). For “Churned Count,” enter the number of customers who canceled during the period. A common mistake is allowing end customers to exceed start + new; if that happens, your inputs are inconsistent.
Review results and format
Toggle “Show decimals” if you prefer decimal form (e.g., 0.10) in addition to percentages (e.g., 10%). Verify that churned customers = start + new − end (or the reverse if using churned count). If the identity doesn’t hold, recheck your counts.

Tip: This calculator uses start-of-period customers as the denominator; if your team uses average customers instead, expect different churn percentages—stay consistent across reports (CalcMastery recommends documenting your convention).

Frequently Asked Questions

The percentage of customers who were active at the start of a period but discontinued by the end; it is the inverse of retention. In contractual/subscription settings, churn is defined relative to the prior period’s active base.
Use churned = Start + New − End, then churn_rate = churned / Start. Retention_rate = 1 − churn_rate. This follows from the standard retention formula Retention = (End − New) / Start.
Divide by the starting customers: churn_rate = Churned / Start. Retention_rate = 1 − churn_rate.
Any is fine; stay consistent. When comparing periods, convert via compounding (see next FAQ) rather than multiplying/dividing by 12 or 3.
annual_churn = 1 − (1 − monthly_churn)^12. monthly_churn = 1 − (1 − annual_churn)^(1/12). Assumes a constant per-month hazard within the year.
Retention_rate = (End − New) / Start, and Retention_rate = 1 − Churn_rate.
Start = 1000, New = 50, End = 950 → Churned = 1000 + 50 − 950 = 100; Churn = 100 / 1000 = 0.10 = 10%; Retention = 90%.
Customer churn counts lost customers; revenue churn measures lost recurring revenue from existing customers (usually start-of-period MRR lost net of upgrades). Use each for different questions.
The standard in subscription (“contractual”) settings is start-of-period customers, aligning with definitions of retention/churn as transitions from last period’s active base. Some practitioners use an average-of-period base, but it mixes acquisition dynamics into the rate.
Negative churn is not interpretable for headcount churn; re-check inputs. Reactivations/returning customers should be counted in “New,” and data anomalies should be corrected so churned = max(0, Start + New − End).
Percent is typical; decimals are the 0–1 form (e.g., 0.10). For reporting, two decimals are customary unless your audience needs more precision.
With an approximately constant per-period churn, expected customer lifetime in periods ≈ 1 / churn_rate (e.g., 2% monthly churn → ~50 months).
Put Start in A2, New in B2, End in C2. Churned in D2: =A2+B2−C2. Churn % in E2: =IF(A2>0,D2/A2,""). Retention % in F2: =1−E2. Annualize from monthly in G2: =1−(1−E2)^12.
Higher retention is strongly associated with profitability in services and subscriptions; classic research shows small retention gains can yield large profit lifts. Use churn/retention as core operating KPIs.

Methodology & Sources

Methodology. Two input methods are supported. (1) Start/End/New: churned = Start + New − End; churn_rate = churned / Start; retention_rate = (End − New) / Start = 1 − churn_rate. (2) Churned Count: churn_rate = Churned / Start; retention_rate = 1 − churn_rate. Units may be Monthly, Quarterly, or Annually; calculations are period-agnostic as long as Start refers to the beginning of the chosen period and End to the end.

Period conversions. For comparability across periods under a constant hazard assumption, annual_churn = 1 − (1 − monthly_churn)^12 and monthly_churn = 1 − (1 − annual_churn)^(1/12). Apply the same compounding to retention: annual_retention = (1 − monthly_churn)^12.

Assumptions & edge cases. Customers are counted at discrete period boundaries; “New” includes acquisitions and reactivations within the period; churn cannot be negative. Start must be > 0 for rates; if Start = 0, rates are undefined. Round displayed percentages to 2 decimals by default; a “Show decimals” toggle can also display rates in 0–1 form. There are no universal “good/bad” thresholds; organizations often set internal, monthly-based bands and, when needed, scale them to other periods using the compounding above.

Bibliography

Peter S. Fader; Bruce G. S. Hardie (2007). How to project customer retention — Journal of Interactive Marketing (Wiley) https://onlinelibrary.wiley.com/doi/abs/10.1002/dir.20074
Accessed 2025-10-25
Wall Street Prep (2024). Retention Rate — Wall Street Prep https://www.wallstreetprep.com/knowledge/retention-rate/
Accessed 2025-10-25
Wall Street Prep (2024). Churn Rate — Wall Street Prep https://www.wallstreetprep.com/knowledge/churn-rate/
Accessed 2025-10-25
Frederick F. Reichheld; W. Earl Sasser Jr. (1990). Zero Defections: Quality Comes to Services — Harvard Business Review https://hbr.org/1990/09/zero-defections-quality-comes-to-services
Accessed 2025-10-25
Peter Fader; Bruce G. S. Hardie; Michael Ross (2022). The Customer-Base Audit: The First Step on the Journey to Customer Centricity — Wharton School Press https://www.pennpress.org/9781613631607/the-customer-base-audit/
Accessed 2025-10-25

Churn Rate Calculator

Results

Insights

Formula

Examples

How to Use the Churn Rate Calculator

Choose the method

Select the period

Enter start customers

Enter new customers

Enter end customers or churned

Review results and format

Frequently Asked Questions

Methodology & Sources

Bibliography

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