Customer Success Glossary

Churn rate is the percentage of customers (logo churn) or recurring revenue (revenue churn) lost over a period. It's the biggest drag on SaaS growth: even modest monthly churn compounds, capping how large the business can get no matter how fast you acquire.

Gross revenue retention (GRR) is the percentage of recurring revenue you keep from existing customers over a period, before any expansion. Because it ignores upsell, GRR can never exceed 100% — making it the purest measure of how much revenue leaks through churn and downgrades.

Net revenue retention (NRR) measures how much recurring revenue you keep and grow from existing customers over a period, including expansion and excluding new logos. NRR above 100% means your installed base grows even with zero new sales — the hallmark of a durable SaaS business.

Customer lifetime value (LTV or CLV) is the total gross-margin revenue you expect from an average customer across their entire relationship with you. It tells you how much you can afford to spend acquiring a customer, and how retention and expansion change the economics of the business.

The LTV:CAC ratio compares the lifetime value of a customer to the cost of acquiring them. It's the headline measure of growth efficiency: roughly 3:1 is considered healthy, below 1:1 means you lose money on every customer, and very high ratios can signal you're underinvesting in growth.

A customer health score is a single metric that summarizes how likely a customer is to renew, churn or expand — blending signals like product usage, support tickets, engagement and survey sentiment. It gives Customer Success an early-warning system to act before a renewal is at risk.

Net Promoter Score (NPS) measures customer loyalty with one question — “how likely are you to recommend us?” on a 0–10 scale. Subtract the percentage of detractors (0–6) from promoters (9–10) for a score from −100 to +100. It's a widely used proxy for sentiment and word-of-mouth growth.

Customer Satisfaction Score (CSAT) measures how satisfied customers are with a specific interaction, product or service, usually via a short “how satisfied were you?” survey. It's expressed as the percentage of positive responses and is best suited to measuring satisfaction at specific touchpoints.

Customer Effort Score (CES) measures how easy it was for a customer to get something done — resolve an issue, find an answer, complete a task. Because reducing effort is a strong driver of loyalty, low-effort experiences often predict retention better than satisfaction alone.

Time to value (TTV) is how long it takes a new customer to reach their first meaningful outcome with your product after signing up. Shorter TTV drives adoption, retention and expansion — because customers who experience value quickly are far more likely to stick around.

Product adoption is the degree to which customers actively use a product and its key features to get value. Measured through usage breadth and depth, it's a leading indicator of retention — low adoption is one of the clearest early signals that an account will churn.

Expansion revenue is additional recurring revenue earned from existing customers through upsell, cross-sell and seat growth. It's the cheapest revenue to win and the engine behind net revenue retention above 100% — often the difference between linear and compounding SaaS growth.

Logo churn and revenue churn measure loss in two different units. Logo churn counts the number of customers lost; revenue churn measures the recurring revenue lost. A business can have high logo churn but low revenue churn if the customers leaving are small — which is why you track both.

Renewal rate is the percentage of customers, contracts or revenue that renew at the end of their term. It's a direct measure of retention at the renewal moment, and can be calculated by logo count or by revenue depending on what you're managing.

A Quarterly Business Review (QBR) is a structured, recurring meeting between a vendor and customer to review progress against goals, demonstrate the value delivered, and plan the next quarter. For Customer Success it's a key moment to reinforce ROI, surface risks and open expansion conversations.

The customer journey and customer lifecycle describe the relationship from two angles. The customer journey is the experience from the buyer's perspective — the steps and touchpoints they go through. The customer lifecycle is the business's view of the stages a customer moves through, from lead to advocate.

Customer onboarding is the process of guiding a new customer from purchase to first value and confident, independent use of your product. Strong onboarding shortens time to value and is one of the highest-leverage points for reducing early churn.

An at-risk account is a customer showing signals that they may churn — declining usage, low engagement, support escalations, a falling health score or a departed champion. Identifying at-risk accounts early lets Customer Success intervene while there's still time to save the renewal.