Calculate customer churn rate, revenue churn rate, net revenue retention, retention rate, and average customer lifetime
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Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.
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Churn is the number that tells you whether retention is working. This churn rate calculator measures it in two ways at once: customers and revenue. Enter your starting customer count, how many you lost, how many you gained, and how your MRR moved over the period. The tool returns customer churn rate, retention rate, gross revenue churn, net revenue churn, net revenue retention, and average customer lifetime. It also places your monthly churn on an industry tier, so you know if you’re best-in-class or losing accounts faster than you’re signing them. Founders, customer success leads, and finance teams use it for quick health checks.
Pick a currency. The symbol appears on all MRR fields. The math stays the same regardless of which currency you choose.
Enter customers at the start of the period. This is your opening cohort, not your total customer base.
Add customers lost during the period. Count only cancellations, not paused or downgraded accounts.
Enter new customers gained. This drives the net change figure but doesn’t affect the churn rate.
Set the period length. Choose a value and pick month, quarter, or year. The tool divides churn into a monthly figure for the benchmark tier.
Enter MRR at the start of the period. Then add MRR lost, MRR expansion (upsells, cross-sells), and MRR contraction (downgrades).
Read the result panel. The hero tile shows customer churn rate. Four tiles below it show gross revenue churn, net revenue churn, and NRR.
The core churn formula divides what you lost by what you started with. Customer churn and revenue churn use the same structure but different inputs.
Formula: Customer Churn Rate = (Customers Lost ÷ Customers at Start) × 100
Formula: Retention Rate = 100% − Customer Churn Rate
Formula: Gross Revenue Churn = (MRR Lost + MRR Contraction) ÷ MRR at Start × 100
Formula: Net Revenue Churn = (MRR Lost + MRR Contraction − MRR Expansion) ÷ MRR at Start × 100
Formula: Net Revenue Retention (NRR) = 100% − Net Revenue Churn
Formula: Monthly Churn = Period Churn ÷ Months in Period
Formula: Average Customer Lifetime (months) = 100 ÷ Monthly Churn Rate
A few things to notice. The numerator for gross revenue churn is MRR lost plus contraction. Expansion sits inside net churn because it offsets what you lost. If expansion exceeds the total of lost plus contraction, net revenue churn goes negative. That’s called negative churn, and it’s the goal for most SaaS companies. The tool reports it as-is rather than clamping to zero.
Average customer lifetime uses a simple approximation: 100 divided by the monthly churn rate. That gives the number of months you’d expect a customer to stay, assuming a steady churn rate. It’s not a full cohort survival model, but it’s the shortcut most teams use for LTV math. If churn is zero, the tool shows infinite lifetime instead of dividing by zero.
The period input drives the monthly conversion. A 6% quarterly churn rate becomes 2% monthly. That monthly figure is what the benchmark tier reads against, since the industry scale is calibrated in months.
A B2B SaaS company closing out Q1. Numbers below.
Inputs: 2,500 customers at start. 175 lost. 240 gained. MRR at start: $180,000. MRR lost: $9,500. Expansion: $4,200. Contraction: $1,800. Period: 1 quarter.
Step 1 – Customer churn. 175 ÷ 2,500 × 100 = 7.0% per quarter.
Step 2 – Retention. 100 − 7.0 = 93.0%.
Step 3 – Monthly churn. 7.0% ÷ 3 months = 2.33% per month.
Step 4 – Net customer change. 240 − 175 = +65. Ending count: 2,565.
Step 5 – Gross revenue churn. (9,500 + 1,800) ÷ 180,000 × 100 = 6.28%.
Step 6 – Net revenue churn. (9,500 + 1,800 − 4,200) ÷ 180,000 × 100 = 3.94%.
Step 7 – NRR. 100 − 3.94 = 96.06%.
Step 8 – Average lifetime. 100 ÷ 2.33 = 42.9 months, or about 3.6 years.
Interpretation: The company lost 7% of customers in the quarter, which annualizes to roughly 28% at the current pace. The monthly figure of 2.33% lands in the “Good” tier. Revenue churn is healthier than customer churn because expansion from existing accounts offsets nearly half of lost and contracted MRR. NRR is 96%, meaning revenue from the existing base shrank 4% over the quarter. That’s below best-in-class (usually above 100%) and worth watching. Average lifetime of 3.6 years gives a solid foundation for LTV if ARPU stays stable.
Divide customers lost by customers at the start of the period, then multiply by 100. For 175 lost out of 2,500, that’s 7%. The calculator converts period churn into a monthly figure for benchmark comparison.
Below 2% monthly is strong for B2B SaaS. Below 1% is best-in-class. Enterprise software often lands under 1%, while SMB SaaS typically sits between 2% and 4%. Consumer subscriptions run higher, often 4% to 7% monthly.
Gross revenue churn includes MRR lost plus contraction, ignoring expansion. Net revenue churn subtracts expansion from that total. If expansion exceeds lost plus contraction, net churn goes negative. Gross churn tells you the leak size; net churn tells you the real outcome.
NRR is 100% minus net revenue churn. It measures what percentage of existing customer revenue you keep after churn, contraction, and expansion. A 110% NRR means the existing base grew 10% without new customers.
Divide 100 by the monthly churn rate. A 2% monthly churn rate gives a 50-month average lifetime. At 5% monthly, it drops to 20 months. The calculator shows both months and years in the annualized view.
They measure different things. Customer churn counts heads. NRR counts dollars. A company can lose 10% of customers but post 105% NRR if the churned accounts were small and expansion from remaining accounts is strong.
Yes. Set the period value and unit at the top of the customer section. A 6% quarterly churn rate becomes 2% monthly, which is what the benchmark tier reads against. Annualized figures appear in the bottom table.
Cancellations and non-renewals count as churn. Paused accounts usually don’t. Downgrades count as contraction, not churn, because the customer is still paying. The MRR contraction field is where you log those.
Above 100% is good. Above 110% is strong. Above 120% is best-in-class for B2B SaaS. Below 90% means revenue from your existing base is shrinking faster than you can replace it with new customers.
Yes. Customer counts, MRR values, and period lengths are all flexible. A company with 40 enterprise customers at $50,000 MRR each works the same as a consumer app with 100,000 users at $10 MRR.
They’re two sides of the same number. Retention rate equals 100% minus customer churn rate. If monthly churn is 3%, monthly retention is 97%. The calculator shows both on the main result panel.
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