Churn Rate Formula: Every Version Explained

There isn’t one churn rate formula — there are several, and each answers a different question. The basic customer churn rate formula is just customers lost divided by customers at the start, but revenue churn, net churn, and annualized churn each modify that in important ways. Reach for the wrong one and you’ll report a number that doesn’t mean what you think it does.

This is a reference for every common version of the churn rate formula, with a worked example for each so you can see exactly how the inputs differ. Bookmark it and use the version that matches the question you’re actually trying to answer.

The basic customer churn rate formula

Customer churn rate = Customers lost during period ÷ Customers at start of period × 100

Start with 800 customers, lose 32, and your churn is 32 ÷ 800 × 100 = 4%. This version counts logos and weights every account equally. It’s the cleanest read on retention but ignores how much each customer pays. For a full walkthrough of applying it, see how to calculate churn rate.

The gross revenue churn rate formula

Gross revenue churn = (MRR lost from cancellations + downgrades) ÷ MRR at start of period × 100

This measures lost recurring revenue only — no expansion offsets. If you start at $40,000 MRR and lose $1,600 to churn and downgrades, gross revenue churn is 4%. Because it never nets out gains, gross revenue churn can never go below zero, which makes it the honest measure of pure leakage. More context in our revenue churn guide.

The net revenue churn rate formula

Net revenue churn = (MRR lost − Expansion MRR) ÷ MRR at start of period × 100

Net churn subtracts expansion revenue — upgrades, added seats, add-ons — from your losses. Suppose you lose $1,600 but existing customers expand by $2,000. Net revenue churn is (1,600 − 2,000) ÷ 40,000 × 100 = −1%. Negative net churn is the holy grail: your existing base grows even if you never add a new customer. This is the flip side of net revenue retention, which expresses the same idea as retention rather than loss.

The average-base churn rate formula

Churn rate = Customers lost ÷ ((Start customers + End customers) ÷ 2) × 100

When your customer count swings a lot within the period, dividing by the starting count alone can distort the rate. Averaging the start and end gives a fairer denominator. Start at 1,000, end at 1,300, lose 50: the average base is 1,150, so churn is 50 ÷ 1,150 × 100 = 4.3% versus 5% on the starting base. Useful for high-growth months; overkill for stable ones.

The MRR churn rate formula (dollar retention view)

A closely related version expresses churn as the complement of dollar retention, which boards and investors often prefer. It’s the same underlying inputs, framed as what you kept rather than what you lost:

MRR churn rate = 100 − (Retained MRR ÷ Starting MRR × 100)

If you start at $50,000 and $47,000 of that MRR is still active at the end of the period (before counting any new customers), your retained share is 94%, so MRR churn is 6%. This framing plugs directly into net revenue retention reporting and makes it easy to move between the "loss" and "retention" ways of describing the same reality. Just be sure everyone reading the report knows which one you’re showing.

The annualized churn rate formula

People often want to turn monthly churn into an annual figure. The tempting shortcut — multiply by 12 — is wrong, because churn compounds on a shrinking base. The correct conversion is:

Annual churn = 1 − (1 − monthly churn) raised to the power of 12

A 5% monthly churn becomes 1 − (0.95)^12 = about 46% annually, not 60%. Getting this right matters a lot when you forecast a full year, and it’s a frequent source of wildly overstated churn projections.

The same compounding logic runs in reverse if you have an annual figure and want a monthly one: take the twelfth root of (1 − annual churn) and subtract it from 1. A 46% annual churn implies roughly 5% monthly, not 3.8%. Whenever you move between time frames, use compounding rather than simple division or multiplication, or your numbers will drift well away from reality.

The involuntary churn rate formula

A version teams often forget isolates churn caused by failed payments rather than deliberate cancellations. It uses the same shape as customer churn but restricts the numerator to accounts lost to declines and expired cards.

Involuntary churn rate = Customers lost to failed payments ÷ Customers at start of period × 100

Involuntary churn is commonly 20–40% of total churn, and unlike voluntary churn it’s recoverable without touching your product — through payment retries and dunning. Breaking it out with its own formula tells you how much of your churn is a billing problem versus a value problem, which points you straight at the cheapest fixes covered in our churn reduction guide.

A quick note on the denominator

Every formula above divides by a base, and the base you choose has to stay consistent. Most teams use the count or MRR at the start of the period. Fast-growing companies sometimes prefer the average of start and end to avoid understating churn during a rapid ramp. Both are defensible; switching between them from month to month is not, because it makes your trend line meaningless. Decide once, write it down, and apply it every period.

Which churn rate formula should you use?

Match the formula to the question:

• How well does the product retain people? Basic customer churn.
• How much revenue is leaking? Gross revenue churn.
• Is my existing base growing on its own? Net revenue churn.
• What’s my full-year loss rate? Annualized churn.

Most teams report customer churn and gross revenue churn monthly, then track net revenue churn as a growth-quality signal. Whatever you pick, keep the definition fixed so your trend stays honest. Get the concept straight before the math, then put the number to work by driving it down.

A worked comparison across formulas

To see how much the formula choice matters, run one dataset through several. Say you start the month with 500 customers and $50,000 MRR. You lose 25 customers: 20 voluntary cancellations worth $1,800, and 5 failed payments worth $400. Existing customers expand by $1,500.

• Customer churn:25 ÷ 500 × 100 = 5%.
• Involuntary churn:5 ÷ 500 × 100 = 1%.
• Gross revenue churn:2,200 ÷ 50,000 × 100 = 4.4%.
• Net revenue churn:(2,200 − 1,500) ÷ 50,000 × 100 = 1.4%.

Four numbers, one month, each true. That’s the whole point of keeping the formulas straight — report the one that answers the question being asked, and label it clearly so no one mistakes your 1.4% net churn for a 5% customer churn.

Skip the manual math

Every one of these formulas depends on clean inputs — consistent MRR, correctly categorized cancellations, and separated involuntary churn. Assembling that from raw Stripe exports each month is where errors creep in. StripeReport connects with a read-only key and computes customer churn, gross revenue churn, and net churn automatically, sending the results to email or Slack daily so your formulas always run on accurate, consistent data. See it alongside continuous Stripe churn rate tracking.

Key takeaways

• There are several churn rate formulas; each answers a different question, so choose deliberately.
• Customer churn counts logos, gross revenue churn counts lost dollars, and net revenue churn subtracts expansion (and can go negative).
• Annualize churn with compounding, not by multiplying by 12 — 5% monthly is about 46% a year.
• Keep your chosen formula and inputs consistent every period so the trend line stays trustworthy.