KPI (Key Performance Indicator)

A KPI (key performance indicator) is one of a handful of numbers chosen to show whether a company, team or campaign is moving toward its goal. Each KPI needs a specific target, a measurement period and an owner.

What is a KPI?

The important word is “key.” The Cambridge Dictionary defines a key performance indicator as one of the most important indicators that show how well a company, project or employee is doing (Cambridge Dictionary, accessed October 2026).

An ad account has dozens of metrics. Only the few tied directly to a business goal are KPIs. Google gives a clear example: Quality Score is a diagnostic tool, not a key performance indicator, and should not be optimized or aggregated with the rest of your data (Google Ads Help, About Quality Score, accessed October 2026).

Marketing KPIs by funnel stage

In GA4, engagement rate is the percentage of sessions that last longer than 10 seconds, or have a key event, or have at least 2 page or screen views (Google Analytics Help, Engagement rate and bounce rate, accessed October 2026). A key event is an event that measures an action particularly important to the success of your business, and any event you collect can become one (Google Analytics Help, Conversions vs. key events, accessed October 2026). Mark your form submission event as a key event and GA4 can report your conversion KPI by channel.

No stage requires a KPI. A small shop running conversion campaigns may only need orders and ROAS. App KPIs (CPI, D1, D7 and D30 retention, LTV, cohort ROAS) are covered in our guide to app marketing KPIs.

KPI vs OKR vs metric

According to Google re:Work, Google uses three to five objectives with about three key results each, graded on a scale of 0 to 1.0. The sweet spot is 60% to 70%; someone who always fully attains their objectives is not setting ambitious enough OKRs (Google re:Work, Set goals with OKRs, accessed October 2026). A KPI works the other way: missing it means there is a problem to fix now.

Example: setting KPIs for a lead generation campaign (hypothetical)

An English language center spends VND 60 million a month on ads and needs 30 new students. Past data: 25% of leads are qualified, and 40% of qualified leads enroll. Work backward from the goal:

• Qualified leads needed = 30 / 40% = 75.
• Total leads needed = 75 / 25% = 300.
• Maximum cost per lead = 60,000,000 / 300 = VND 200,000.
• At a CPC of VND 4,000, the budget buys 15,000 clicks, so the landing page needs a conversion rate of 300 / 15,000 = 2%.

The KPIs are 300 leads, no more than VND 200,000 per lead, and 30 students. CTR, CPC and landing page conversion rate are diagnostic metrics: when a KPI slips, open them to see whether the problem is in the ad or on the landing page.

Frequently asked questions

How many KPIs should a campaign have?

There is no standard number. One or two KPIs per goal is usually enough to make decisions. A list of 15 KPIs is usually diagnostic metrics with the wrong label.

How are HR KPIs different from marketing KPIs?

HR KPIs grade individual people and are often tied to bonuses. Marketing KPIs grade channels or campaigns.

Is ROI a KPI?

Yes, when the goal is profit. See ROI for how to calculate it.

If you need to build a KPI set that runs from a revenue target down to each ad channel, contact Adtek.