Newsletter KPIs: The 12 Most Important Metrics

If you run a newsletter, you measure it — otherwise you optimise the wrong thing. At the same time, most dashboards are full of numbers nobody understands. This post organises the twelve KPIs that really matter, explains them briefly, and gives a current DACH benchmark. At the end you know exactly which numbers belong in your weekly reporting.

Upfront: good metrics drive decisions

A KPI is useful only if you derive a decision from it. "We had 8,500 opens" is not a KPI, it is reporting. A KPI is identified by the fact that its movement triggers an action.

The 4 deliverability KPIs

1. Delivery rate

Share of emails accepted by the recipient server.

Formula: (Sent − hard bounces − soft bounces) / sent

Benchmark: > 98 %. Anything below signals poor list hygiene or deliverability issues.

Action on deviation: clean bounces, check SPF/DKIM/DMARC, verify warm-up.

2. Bounce rate (hard and soft)

Hard bounce = address does not exist. Soft bounce = temporary (mailbox full, server down).

Benchmark: hard bounce < 0.5 %, soft bounce < 2 %.

Action: remove hard bounces from the sending list IMMEDIATELY — otherwise reputation damage.

3. Spam complaint rate

Share of recipients who click "mark as spam".

Benchmark: < 0.1 % per campaign, < 0.3 % monthly average.

Action if breached: reduce frequency, raise relevance, make the unsubscribe link more prominent.

4. Inbox placement

Does your newsletter land in the inbox vs. spam folder? Measurement tool: GlockApps, Mailaura spam check.

Benchmark: > 95 % inbox placement.

The 4 engagement KPIs

5. Open rate

Formula: unique opens / delivered

DACH benchmark 2026: 25–35 % (industry-dependent).

Caveat 2026: since Apple's Mail Privacy Protection (MPP), open rates are artificially inflated (automatic preloads), sometimes by 10–20 percentage points. Treat open rate as a tendency, not a hard number.

6. Click-through rate (CTR)

Formula: unique clicks / delivered

Benchmark: 2–4 %.

The hardest, most meaningful engagement number. Reacts authentically to content quality and CTA design.

7. Click-to-open rate (CTOR)

Formula: unique clicks / unique opens

Benchmark: 10–15 %.

Measures how well content convinces those who actually read the email. Unaffected by MPP.

8. Unsubscribe rate

Formula: unsubscribes / delivered

Benchmark: < 0.5 % per campaign.

Action if breached: frequency too high or content not relevant.

The 4 business KPIs

9. List growth rate

Formula: (New subscribers − unsubs − bounces) / total list size

Benchmark: > 2 % net per month.

If this goes negative, your list is shrinking. Three consecutive months below: internal alarm.

10. Revenue per email (RPE)

Formula: total campaign revenue / delivered

Benchmark: strongly industry-dependent. DACH e-commerce: 0.20–0.80 €. B2B: 1–5 € (due to deal size).

Crucial for business-case arguments.

11. Conversion rate

Formula: conversions (purchase, sign-up, form) / clicks

Benchmark: 1–5 % depending on goal.

Measures whether the click pays economically. Connected to landing-page optimisation.

12. Return on investment (ROI)

Formula: (revenue − tool cost − labour) / total cost

DACH email-marketing benchmark: 30–45 € revenue per 1 € spend (DMA study, confirmed by internal data).

The ultimate KPI for leadership.

Secondary KPIs (not unimportant, but not in dashboard)

• Forward rate: how often is the mail forwarded? Strong virality indicator.
• Mobile open share: shows if your layout must be mobile-first (usually > 70 %).
• Time to first open: quick opens = high relevance.
• Forward-to-sign-up: of forwarded mails, how many drive new sign-ups?

How to structure reporting

Level 1 — quick dashboard (3 numbers):

• Open rate (trend)
• Click-through rate
• Unsubscribe rate

Level 2 — weekly reporting (7 numbers):

• Delivery rate, bounce rate, spam rate
• Open rate, CTR, CTOR
• Unsubscribe rate

Level 3 — monthly management report (12 numbers):

• All of the above + list growth rate, RPE, conversion rate, ROI

DACH benchmarks by industry (2026)

Above average — congratulations. Clearly below, three most likely reasons:

1. List quality (old, inactive contacts)
2. Content (not relevant to audience)
3. Frequency (too rare or too frequent)

What NOT to use as a KPI

• Absolute open count — says nothing about quality.
• Raw click count — worthless without a reference.
• Social share count — usually irrelevant for newsletters.
• Number of campaigns sent — activity is not results.

How Mailaura helps

The dashboard ships all twelve KPIs out of the box, plus:

• Trend chart over 12 campaigns (spot unusual outliers).
• Heatmap by weekday and hour.
• Benchmark comparison to anonymised industry values.
• Export API if you want to pull KPIs into an external BI system.

Conclusion

Newsletters are the most profitable marketing channel only if you measure them. Three numbers on the dashboard are mandatory (opens, clicks, unsubs), seven in weekly reporting, twelve in the monthly report. Crucial: derive a concrete action from every KPI movement. If your current tool does not deliver these numbers, have a look at Mailaura or the newsletter software comparison.