How to Check and Improve Your Sender Score for Better Email Performance

✨ Key takeaways

⭐ Sender Score reflects how trustworthy your emails appear to mailbox providers.

⭐ Sender Score is calculated based on your past 30 days of sending behavior.

⭐ A high score improves deliverability; a low one undermines your campaign.

⭐ Sender Score is not the same as sender reputation.

⭐ You can check your score using specialized tools.

An email campaign can be evaluated from many angles. You can judge it by its open rates and its click-through rates. You might assess it from engagement metrics to creative execution or through the lens of visual design and structure of the copy. 

But amid these scattered indicators, what’s often missing is a single, unifying metric—the equivalent of body temperature for email. A baseline health check, if you want. That metric is your Sender Score.

If you’re wondering, “What is Sender Score?” in this article we’ll talk exactly about this. We will also discuss how to improve the Sender Score, what it’s made of, how it’s different from sender reputation, and why it plays a critical role in your email deliverability and overall marketing performance. And while it doesn’t replace deeper analysis, it gives you something that most other metrics can’t: a high-level snapshot of how mailbox providers see you.

What Is Sender Score? 

There are many things in email marketing that seem somewhat vague: good content, engagement, deliverability. Sender Score is not one of them. First of all, it’s a number. A number between 0 and 100, assigned to your IP address. While this definition might sound bland and lack creativity, its advantage is that it is very direct and specific. Sender Score was developed by Return Path, a leading provider of email deliverability solutions that was later acquired by Validity. This indicator was designed to be the one benchmark that marketers could point to and say, “See? We’re not spammers.”

That number does not measure the beauty of your email campaign. It similarly does not care about the cleverness of your subject lines or how many emojis you use. What it measures is far more complex and important: the reputation of your sending infrastructure. It monitors the behavior of your campaigns by looking for both inconsistencies and the positive patterns. You can see it as a valuable tool: Sender Score gives marketers an objective, measurable way to assess their sending health.

This number becomes especially important in light of requirements set by inbox providers that are getting increasingly stricter. Due to those requirements, they’ve outsourced part of the decision-making to scoring systems like this one. In this context, your email Sender Score can be compared to your passport—the higher the number, the more places you can go. The lower it gets, the fewer chances your emails have to be seen and engaged with. 

Sender Score vs. Sender Reputation 

Sender Score and sender reputation are related and often used interchangeably, but they serve different purposes and are calculated differently.

Your Sender Score is a third-party metric that gives you a quantifiable benchmark of your sending behavior, based on public signals like spam traps, complaint rates, and bounce data. It’s an external metric that you can check, track, and act upon.

Sender reputation, by contrast, is how mailbox providers evaluate your sending identity within their own systems. It’s internal and often more nuanced. Each provider has its own model, and each weighs factors differently. For example, Gmail places strong emphasis on recipient engagement—opens, replies, deletions, and how often users move your emails between folders. Microsoft systems tend to focus more on complaint rates and authentication alignment. Yahoo looks closely at bounce patterns and infrastructure stability.

These differences explain why the Sender Score is so important: while you can’t fully control every variable in each provider’s system, a strong email Sender Score helps you align with the broad expectations that most major inbox providers use as a baseline for trust.

How the Sender Score Is Calculated

Now that we’ve established the Sender Score as your passport to the inbox, the next question is, what exactly determines your visa eligibility? It is neither your intent nor your effort. It is something much more tangible—your actual behavior. The system doesn’t care if you’re a small business trying your best or a global brand with an established reputation. It looks at the signals you send out—and registers them up into assessment.

The score itself is calculated based on a rolling 30-day average, which means today’s mistake might still haunt you for the next few weeks. It also means your recent habits matter more than your historic ones (unless you repeat them regularly).

The core components that influence your email Sender Score include:

👉 Spam trap hits: Sending emails to spam traps indicates poor list hygiene or improper acquisition practices. It suggests that you may be emailing users without valid consent.

👉 Unknown users: These are email addresses that no longer exist or were entered incorrectly. A high number of unknown users implies that your database is outdated or unverified.

👉 Complaint rates: This refers to the number of recipients who mark your emails as spam. High complaint rates are a strong negative signal for inbox providers and will significantly lower your Sender Score.

👉 Message volume and consistency: Large fluctuations in your sending volume, especially sudden spikes, are seen as unreliable behavior. Consistent, predictable sending patterns are favored.

👉 Blocklist status: If your IP address is listed on one or more industry blocklists, it directly impacts your score. Being on a blocklist is a strong indication that your emails are unwanted or potentially harmful.

Together, these factors provide a comprehensive view of your sending behavior. A strong Sender Score reflects responsible practices and good standing with ISPs. On the contrary, a weak one signals potential risk, and with it, reduced inbox placement.

What Your Sender Score Means 

Once you know your Sender Score, the next step is about figuring out what that number actually indicates about your email performance. It may seem like a simple range from 0 to 100, but, the implications are significant—especially when the number drops below 60. In those cases, it might start affecting your deliverability rates and campaign ROI.

Here’s how to interpret your score:

🟢 91–100: Excellent

This score range reflects strong sending practices, low complaint rates, and consistent engagement. Mailbox providers are likely to trust your IP, resulting in high inbox placement and minimal filtering.

🟡 71–90: Good

You are in a generally healthy range, but there may be small issues—such as occasional bounces or minor complaint spikes—that could grow if left unaddressed. Monitoring and proactive list maintenance are recommended.

🟠 51–70: Risky

This range suggests that inbox providers are beginning to see your sending behavior as problematic. Common issues may include outdated lists, inconsistent volume, or rising complaint rates. Without changes, deliverability will likely continue to decline.

🔴 0–50: Poor

A Sender Score within this range indicates serious reputation issues. Your emails are at high risk of being blacklisted or automatically routed to spam. Recovery will require a thorough audit of your practices and gradual re-establishment of trust.

When you understand the actual meaning that stands behind those numbers, you can align your email practices with the standards mailbox providers expect. While a higher score doesn’t always guarantee perfect results, a low one almost always correlates with performance issues.

Why the Sender Score Matters for Email Marketers 

By this point, it should be clear that your Sender Score functions as an overall health indicator of your email campaigns. When it is strong, it’s usually because your fundamentals, like clean lists and minimal complaints, are in good shape. That health is reflected not just in the inbox, but across your ROI metrics.

But when your Sender Score drops, it often coincides with, or even causes, measurable issues, such as filtered-out emails or slowed conversions. A low score is a signal that tells you that something in your campaign is not working right. In other words, a high score means your email ecosystem is functioning properly. A low score means you’re either underperforming or about to.

How to Check Your Sender Score

✅ Choose a reliable tool

The most straightforward way to check your email Sender Score is through SenderScore.org, developed by Validity. It provides a score between 0 and 100, along with a breakdown of complaint rates, volume trends, and potential red flags. For broader insights, tools like Cisco Talos Intelligence, BarracudaCentral, or other email checkers can also be useful. While they don’t provide sender scores specifically, they offer visibility into IP reputation, blocklist status, and general sender credibility. This functionality makes them valuable for cross-checking your standing across different filtering systems.

✅ Gather key information

• Identify the IP address used to send your email campaigns (this is critical—Sender Score is tied to the IP, not the domain).
• If you’re using a shared IP through an ESP, check with your provider for access to their sender reputation tools.

✅ Run the check

1. Go to SenderScore.org.
2. Enter your sending IP address.
3. Review the report, paying close attention to:
   • Sender Score (0–100)
   • Complaint rate
   • Spam trap hits
   • Volume trends
   • Blocklist alerts

✅ Interpret and act

• Score above 90: Excellent result. Maintain current practices.
• Score between 71 and 90: Generally good, but review any rising complaints or irregular patterns.
• Score below 70: Investigate causes immediately. Start with list quality, bounce rates, and complaint logs.

By regularly going through this checklist and assessing your Sender Score, you’ll be getting a clear picture of how your email practices are perceived over time and a clear path for course correction if things start to look less optimistic.

How to Improve a Low Sender Score 

Start by addressing the core issues:

🔹 Clean your list: Remove invalid or inactive addresses. Use confirmed opt-in wherever possible to ensure consent and accuracy.

🔹 Stabilize your sending volume: Sudden spikes or irregular sending patterns can trigger deliverability issues. Establish a consistent cadence and stick to it.

🔹 Reduce complaints: Make it easy for users to unsubscribe. Avoid misleading subject lines, excessive frequency, or irrelevant content.

🔹 Authenticate your emails: Proper use of SPF, DKIM, and DMARC is essential. Without authentication, your emails are more likely to be flagged or rejected.

🔹 Monitor your infrastructure: Regularly check your domain and IP for blocklist appearances and keep a close eye on bounce and complaint rates.

These recommendations, while they might sound obvious, are the fundamentals that ensure consistent health of your email campaigns. What’s even more important—they cannot be quickly fixed and require ongoing attention. Only with consistency can you show inbox providers that you send responsibly and respect your audience.

To Sum Up

The Sender Score doesn’t try to capture the nuance of your copy or the elegance of your layout. It won’t tell you which CTA performed better. But what it offers is something more fundamental—a way to measure the trust your emails carry before they’re even opened. 

Throughout this article, we’ve explored how Sender Score works, how it’s calculated, and yes, even answered the question “What is a good Sender Score?”—as a reference point for understanding your place in the broader email delivery system.