How to measure Net Promoter Score

A survey-based score from the 0–10 'how likely are you to recommend us?' question, taking promoters (9–10) minus detractors (0–6).

NPS = % Promoters − % Detractors

Why it matters: A leading indicator of word-of-mouth growth and retention. Not a financial metric, but persistently low NPS predicts churn and stalled organic acquisition.

3 tools that produce NPS

Side-by-side: how each tool produces this number, what to read before adopting, and where to find the official docs. Saasly does not integrate with these tools — this is a reference so you can pick the right one for your stack.

ToolCategoryHow it produces NPSPricing
MixpanelProduct analyticsComputed (SQL / export)Free up to 1M events/month; from $24/mo (Growth) to enterprise.
AmplitudeProduct analyticsComputed (SQL / export)Free up to 50K MTU; from $49/mo (Plus).
PostHogProduct analyticsComputed (SQL / export)Free up to 1M events/month; usage-based after.

Per-tool: what to know before you plug it in

Mixpanel

Computed (SQL / export)

Product analytics

Event-based product analytics for funnels, retention, and cohort analysis.

Before you adopt: Mixpanel has no built-in NPS survey — you send each 0–10 response as an event property, then bucket promoters/detractors in a report. Response-rate bias is the trap: in-app survey takers skew toward your most engaged users, flattering the score.
Pricing: Free up to 1M events/month; from $24/mo (Growth) to enterprise.
Official docs for NPS Mixpanel home

Amplitude

Computed (SQL / export)

Product analytics

Event-based product analytics with strong cohort and behavioral retention tooling.

Before you adopt: No native NPS survey — capture 0–10 scores as event properties and segment promoters vs. detractors in a chart. Same self-selection bias as any in-product survey: engaged users respond more, so the score skews high.
Pricing: Free up to 50K MTU; from $49/mo (Plus).
Official docs for NPS Amplitude home

PostHog

Computed (SQL / export)

Product analytics

Open-source product analytics with self-hosting option.

Before you adopt: PostHog Surveys can collect the 0–10 question in-app, but you still bucket promoters minus detractors yourself in an insight. Watch sampling bias — in-product respondents skew toward active users and inflate the score.
Pricing: Free up to 1M events/month; usage-based after.
Official docs for NPS PostHog home

Already have your numbers? Run the math.

The Saasly Calculator computes NPS (and 15 other SaaS metrics) from manual input — useful when you've pulled the underlying numbers out of one of the tools above and want a quick sanity check with industry benchmark percentiles.

Open the calculator

Other metrics

How to measure Customer Lifetime Value
The total gross profit a single customer is expected to generate over their entire relationship with you.
How to measure Customer Acquisition Cost
The fully-loaded cost of acquiring one paying customer in a given period.
How to measure Monthly Recurring Revenue
The normalized monthly value of every active subscription, regardless of billing period.
How to measure Customer Churn Rate
The percentage of customers who cancel in a given period. Counts logos, not dollars.
How to measure Net Revenue Retention
How much revenue a cohort of existing customers generates compared to where they started — including expansion, contraction, and churn.
How to measure CAC Payback Period
The number of months of gross profit from a customer required to recover the cost of acquiring them.
How to measure SaaS Quick Ratio
The ratio of revenue gained (new + expansion) to revenue lost (churn + contraction) in a period.
How to measure Magic Number
Annualized net-new ARR generated for each dollar of the prior quarter's sales & marketing spend.
How to measure Gross Margin
The percentage of revenue left after the direct cost of delivering the service (hosting, support, payment fees, third-party APIs).
How to measure Trial-to-Paid Conversion
The percentage of users who start a trial and become paying customers.
How to measure DAU/MAU Ratio
The share of monthly active users who use the product on a given day — the standard 'stickiness' measure.