How to calculate the monetary value of email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 19 Apr 2025
Updated 15 Aug 2025
6 min read
Email deliverability is often seen as a technical concern, relegated to the background while marketing teams focus on content and design. However, the reality is that without strong deliverability, even the most perfectly crafted email campaign is rendered ineffective. If your emails don't reach the inbox, they can't be opened, clicked, or convert, directly impacting your bottom line.
Quantifying this impact in monetary terms can be challenging, but it is crucial for justifying investment in deliverability resources, whether that means dedicated personnel, advanced tools, or specific strategies. Understanding the financial value transforms deliverability from a mere technical hurdle into a strategic business asset.
The hidden costs of poor deliverability
Poor deliverability directly translates to missed opportunities. Every email that ends up in the spam folder, or bounces, represents a lost chance for engagement, a missed sale, or an uncommunicated update. This loss isn't just theoretical, it has a tangible financial cost that accumulates over time.
Beyond lost conversions, poor inbox placement means wasted marketing spend. Every dollar invested in email content creation, list building, and sending infrastructure is devalued if a significant portion of your messages never reach their intended recipients. It is like pouring water into a leaky bucket, where your efforts are diminished before they can yield returns.
Furthermore, consistent deliverability issues can lead to your sending domain or IP address being placed on an email blocklist (or blacklist). This can severely hinder all future email campaigns, making it even harder to reach your audience and recover your sender reputation. It's essential to understand how to assess the impact of an unknown email blacklist to mitigate these risks.
Calculating lost revenue from undelivered emails
The most direct way to calculate the monetary impact of deliverability is by quantifying the lost revenue from emails that fail to reach the inbox. This requires you to know your total emails sent, your delivered emails, and your average revenue generated per delivered email.
To calculate the potential lost revenue, subtract your delivered emails from the total emails sent to find the number of undelivered messages. Then, multiply this number by your average Revenue Per Email (RPE). The simple formula for lost revenue is:
Lost revenue formula
(Total Emails Sent - Delivered Emails) * Average Revenue Per Delivered Email
Indicates the percentage of emails reaching the inbox, directly correlating to potential reach and campaign effectiveness.
Revenue per email (RPE)
Total revenue from campaign / Number of delivered emails
The direct financial return for each email successfully delivered, vital for calculating lost opportunity.
Customer lifetime value (CLV)
Average purchase value × Purchase frequency × Customer lifespan
A long-term view that shows the cumulative value of maintaining a subscriber, heavily influenced by consistent inbox delivery.
Broader financial implications and KPIs
Beyond direct lost revenue, consider the broader financial implications of email deliverability. The average ROI for email marketing campaigns is reported to be significant, with some studies suggesting an average ROI of email marketing campaigns of $36 for every $1 spent. This high return is only possible if your emails consistently reach the inbox. Every percentage point lost in deliverability erodes this impressive ROI.
Viewing deliverability as a preventative measure, much like a car service plan, helps in understanding its value. While skipping a service might not cause immediate breakdown, it increases the risk of future, more costly problems. Similarly, proactive deliverability management reduces the risk of major issues like blocklisting or severe inbox placement degradation, thereby protecting future revenue streams and your brand's reputation. This is key to aligning deliverability and compliance goals with revenue.
Proactive management
Regular monitoring: Continuous oversight of key metrics, authentication, and sender reputation.
Risk mitigation: Addresses potential issues before they escalate into major problems, preventing large-scale revenue loss.
Long-term health: Builds and maintains a strong sender reputation, ensuring consistent inbox placement over time.
Key Performance Indicators (KPIs) like open rates, click-through rates, bounce rates, and spam complaint rates are not merely vanity metrics, they are vital indicators of your sender reputation and directly influence inbox placement. Monitoring KPIs to monitor email deliverability trends on a granular, domain-by-domain basis, provides a clear view of your deliverability health. Internet Service Providers (ISPs) track monitoring email engagement and its impact on deliverability closely.
Finally, poor deliverability can lead to increased customer support inquiries as recipients miss important communications like order confirmations, password resets, or critical updates. These unquantified operational costs can add up, impacting resources and customer satisfaction. Understanding reasons why your emails fail is the first step toward preventing these issues and ensuring emails consistently reach their intended recipients.
Leveraging data for advocacy
To effectively advocate for deliverability resources, you must present the monetary value in clear, quantifiable terms. This involves regularly tracking your key deliverability metrics and translating them into potential revenue gains or losses. For example, if you can demonstrate that a 1% improvement in inbox placement led to a 2% increase in sales, you have a powerful argument.
Showing how improvements in deliverability directly correlate with increased conversions or reduced operational costs provides a compelling business case for investment in deliverability expertise, tools, or staff. It highlights the strategic importance of ensuring your messages consistently land in the inbox. You can learn more about the ways to measure deliverability and inbox placement.
Views from the trenches
Best practices
Regularly analyze email performance broken down by mailbox provider to identify specific deliverability challenges and opportunities.
Implement robust email authentication protocols such as SPF, DKIM, and DMARC to build trust with mailbox providers.
Segment your email list and tailor content to improve engagement, which positively impacts sender reputation and deliverability.
Common pitfalls
Overlooking the 'hidden' costs of poor deliverability, like increased support tickets or brand damage, when calculating its value.
Relying solely on overall delivery rates without investigating per-domain or mailbox provider performance.
Failing to link deliverability metrics directly to business outcomes, making it harder to justify investment.
Expert tips
Consider your email program's importance to overall revenue when deciding whether to hire a dedicated deliverability professional.
Use a car service plan analogy to explain the preventative nature of deliverability to stakeholders who may not fully grasp its technicalities.
Start by assigning someone to regularly review domain performance using standard KPIs before committing to a full-time role.
Marketer view
Marketer from Email Geeks says they extrapolated the value of inboxing at specific domains by looking at past performance and applying that to currently undelivered segments. For example, if Hotmail inboxing was strong six months ago with an average value of $1 per recipient, then getting 1,000 emails to Hotmail's inbox again would equate to $1,000 in potential revenue.
2020-07-29 - Email Geeks
Marketer view
Marketer from Email Geeks says that if a user does not see the email, then all expenditure on the email program is wasted. The value of deliverability, therefore, is essentially the entire email marketing budget.
2020-07-30 - Email Geeks
Invest in your inbox reach
Calculating the monetary value of email deliverability transforms it from a technical detail into a critical business metric. By quantifying lost revenue, understanding the full scope of wasted marketing spend, and recognizing the hidden costs of poor inbox placement, you can build a strong case for prioritizing deliverability efforts.
Ultimately, investing in robust deliverability strategies is an investment in your entire email marketing ecosystem. It ensures that your valuable messages, and the conversions they are designed to drive, consistently reach your audience, thereby maximizing your return on investment and safeguarding your brand's communication channels. This is how you ensure that your emails hit the inbox instead of spam.
