Definition
ARPU (Average Revenue Per User) is a key performance metric that calculates the average revenue attributed to each active email subscriber over a given period. It tells you how much value each person on your email list generates and is a fundamental metric for evaluating the health and profitability of your email program.
ARPU is widely used across subscription businesses, ecommerce, and media to track per-subscriber value over time. Changes in ARPU signal whether your email strategy is improving or declining in effectiveness.
Formula
ARPU = Total Email-Attributed Revenue / Number of Active Subscribers
Example Calculation
If your email campaigns generate £100,000 in a month and you have 50,000 active subscribers:
ARPU = £100,000 / 50,000 = £2.00 per subscriber per month
This means each subscriber generates £2.00 in revenue per month on average.
ARPU vs Related Metrics
| Metric | Formula | What It Tells You |
|---|---|---|
| ARPU | Revenue / Subscribers | Value per individual subscriber |
| Revenue per email | Revenue / Emails sent | Value per individual send |
| Revenue per campaign | Revenue / Campaigns | Value per campaign effort |
| LTV | ARPU x Average Lifespan | Long-term subscriber value |
| Subscriber equity | Forward-looking ARPU | Future value potential |
Average Benchmarks
| Industry | Monthly ARPU | Annual ARPU |
|---|---|---|
| Ecommerce | £1.50 - £5.00 | £18 - £60 |
| B2B SaaS | £3.00 - £15.00 | £36 - £180 |
| Media/Publishing | £0.50 - £2.00 | £6 - £24 |
| Non-profit | £0.20 - £1.00 | £2.40 - £12 |
How to Improve Email ARPU
- Segment high-value subscribers: Identify subscribers with the highest ARPU and create campaigns specifically for them. Protect and nurture this segment.
- Improve conversion rates: Higher click-to-convert rates directly increase ARPU without requiring more subscribers or sends.
- Increase purchase frequency: Encourage repeat purchases through automated post-purchase and replenishment campaigns.
- Reduce list churn: Losing subscribers lowers your active count and can decrease ARPU if the churning subscribers were above average.
- Personalise offers: Targeted product recommendations and behaviour-based offers consistently outperform broadcast campaigns in per-subscriber revenue.
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Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
Abandoned Cart Email
An abandoned cart email is a triggered message sent to online shoppers who added items to their cart but did not complete the purchase.
Abandoned Cart Email
An abandoned cart email is an automated message sent to customers who added items to their online shopping cart but left without completing the purchase. It is one of the highest-converting email types in ecommerce.
Abuse Complaint
An abuse complaint is a report from a recipient who marks an email as spam, which negatively affects sender reputation and deliverability.
AI Email Summary
An AI email summary is a short, machine-generated overview of an email's key points, shown by Gmail, Outlook and Apple Mail before a recipient opens the message. It is reshaping how email marketers think about subject lines, preview text and open rates.
AI Inbox Summary
An AI inbox summary is an AI-generated digest that condenses unread email — often highlighting news, actions and senders — changing how clearly your marketing email reaches and engages subscribers.
Frequently Asked Questions
Measure ARPU monthly for active reporting and quarterly for strategic analysis. Monthly measurement captures campaign performance trends. Quarterly measurement smooths out seasonal variation.
Use active subscribers (those who have engaged within 90 days) for your primary ARPU calculation. Including disengaged subscribers inflates your subscriber count and artificially lowers ARPU. Measure both active and total list ARPU separately.
ARPU is a gross metric that typically does not account for email program costs. Net ARPU (revenue minus email costs per subscriber) can be negative if your email platform, team, and tooling costs exceed attributed revenue.
B2B ARPU is typically higher because individual deal values are larger and lists are smaller. B2C ARPU relies on higher volume and conversion frequency. Comparing ARPU across different business models requires industry-specific benchmarking.
Common causes include list growth outpacing revenue growth, declining engagement rates, reduced purchase frequency, increased competition in the inbox, or economic factors affecting customer spending.