NPS, CSAT, and CES are the three most widely used customer experience metrics. Each measures something different, uses a different formula, and suits a different point in the customer journey. This article gives you the exact formulas, worked examples, and a plain guide to when each metric applies.

What Is Net Promoter Score (NPS)?

Net Promoter Score measures customer loyalty by asking a single question: "On a scale of 0–10, how likely are you to recommend us to a friend or colleague?"

Respondents fall into three groups based on their score:

• Promoters — scored 9 or 10. Loyal customers likely to refer others.
• Passives — scored 7 or 8. Satisfied but not enthusiastic; excluded from the NPS calculation.
• Detractors — scored 0 through 6. Unhappy customers who may discourage others.

NPS was developed by Fred Reichheld and published in the Harvard Business Review in 2003. Its appeal is simplicity: one question, one number, one trend to track over time.

How to Calculate NPS

Follow these steps to calculate NPS from raw survey responses.

Step 1: Run the survey

Ask the standard NPS question on a 0–10 scale. Collect enough responses to be statistically meaningful — a few dozen at minimum, more for high-confidence results.

Step 2: Classify responses

• Promoters = scores of 9 or 10
• Passives = scores of 7 or 8
• Detractors = scores of 0 through 6

Step 3: Calculate percentages

Divide the count in each group by the total number of respondents (not just Promoters and Detractors) and multiply by 100. Passives are included in the total but not in the formula itself.

Formula

NPS = % Promoters − % Detractors

Worked example

You collect 50 responses: 20 Promoters, 15 Passives, 15 Detractors.

• % Promoters = 20 / 50 × 100 = 40%
• % Passives = 15 / 50 × 100 = 30% (not used in formula)
• % Detractors = 15 / 50 × 100 = 30%
• NPS = 40 − 30 = 10

NPS ranges from −100 (every respondent a Detractor) to +100 (every respondent a Promoter). A positive score means more Promoters than Detractors. A negative score is the reverse.

Because the absolute number varies by industry, region, and survey method, track your NPS trend over time rather than fixating on a single figure. Context matters more than the number itself. If you are running NPS surveys through your contact centre software, segment results by channel and agent cohort for the most actionable data.

What Is CSAT?

Customer Satisfaction Score (CSAT) measures how satisfied a customer was with a specific interaction or experience — a support call, a delivery, an onboarding session. It is not a measure of overall loyalty.

The standard CSAT question is: "How satisfied were you with [this interaction]?" answered on a 1–5 or 1–10 scale, or sometimes with descriptive options (Very Satisfied to Very Dissatisfied). CSAT surveys are typically sent immediately after a transaction while the experience is fresh.

Because CSAT is transactional, it is well suited to call recording review workflows — you can correlate CSAT scores with specific call recordings to identify what high-scoring interactions look like.

How to Calculate CSAT

The most common CSAT calculation counts only responses at the satisfied end of the scale — typically 4 and 5 on a 5-point scale, or 7–10 on a 10-point scale — and expresses them as a percentage of all responses.

Formula

CSAT (%) = (Number of satisfied responses ÷ Total responses) × 100

Worked example

You receive 100 survey responses after support contacts. 72 customers gave a score of 4 or 5 on a 5-point scale.

• Satisfied responses = 72
• Total responses = 100
• CSAT = (72 / 100) × 100 = 72%

What counts as "satisfied" depends on how you define your scale. On a 5-point scale, 4 and 5 are the typical satisfied threshold. On a 10-point scale, 7–10 is common. Be consistent — changing the threshold between measurement periods makes trends meaningless.

An alternative is to average all scores (a simple mean). This is easier to calculate and preserves granularity, but it is less commonly used for CSAT reporting because it conflates neutral and negative responses differently depending on scale design.

What Is CES?

Customer Effort Score (CES) measures how easy or difficult it was for a customer to resolve an issue or complete a task. The standard question is: "How easy was it to resolve your issue today?" answered on a 1–7 scale where 1 = Very Difficult and 7 = Very Easy.

CES was introduced by researchers at CEB (now Gartner) in a 2010 Harvard Business Review article. Their finding: reducing customer effort is more predictive of retention and reduced churn than customer delight. Customers who experience low effort are more likely to repurchase and less likely to share negative word-of-mouth.

CES is best used after service interactions — support calls, chat, complaint resolution — where friction directly affects the customer's willingness to return. It is less useful for measuring product satisfaction or brand perception.

How to Calculate CES

CES is reported as a simple average (arithmetic mean) of all scores collected.

Formula

CES = Sum of all scores ÷ Number of responses

Worked example

You collect 50 responses after service interactions. The scores total 275.

• Sum of scores = 275
• Number of responses = 50
• CES = 275 / 50 = 5.5 (on a 7-point scale)

A higher CES score means customers found the experience easier. A lower score signals friction that needs investigation.

Important: Some implementations invert the scale so that 1 = Very Easy and 7 = Very Difficult. Always specify your scale direction when reporting CES scores, especially when comparing across teams or time periods. An inverted scale makes a low score good — the opposite of the standard convention.

NPS vs CSAT vs CES: When to Use Each

These three metrics are complementary, not interchangeable. Here is how to match the metric to the measurement moment.

In a contact centre context, CSAT and CES work together at the interaction level — CSAT tells you whether customers were satisfied; CES tells you whether the resolution was easy. Run both after each contact. Use NPS quarterly to track whether accumulated experiences are building loyalty or eroding it.

For a broader view of how these metrics fit into operational strategy, see our coverage of contact center trends and how teams are using call center scripts to deliver more consistent experiences that move CSAT and CES scores.

Frequently Asked Questions