Checking an email address list should be the first step in sending an email marketing campaign. However, many digital marketers still struggle to get their messages to the recipients on their list.

According to a Campaign Monitor study, the global average bounce rate for all industries is 0.7%. While eliminating bounce may be impossible, decreasing it to its minimum and keeping it within or below the average is perfectly achievable.

How can you do it? Through email verification. That's why we have listed below 4 ways to check an email address and ensure a minimum bounce rate. But first things first!

What does it mean to check an email address?

Checking an email address is part of the process of cleaning your mailing list, that is, removing old or inactive contacts from your database. They can be contacts that no longer interact with your emails or old inactive email addresses or that have become spam traps.

Why should you do that?

You should maintain good hygiene of your mailing list as it can affect your delivery capacity or, in other words, the number of emails that reach your subscribers' inboxes. Why should you bother with it? Because it is what allows you to increase the opening rate of your email campaigns.

ISPs (Internet Service Providers) obtain information from their statistics. From your open rate, they try to gauge your subscribers' interest in the content that you send them. A low open rate can indicate to ISPs that your subscribers are not interested.

You should clean your mailing list so that, when ISPs read your open rates, they do not deem it unsatisfactory and send your emails to the Spam folder.

If it does happen, your open rate will decrease even further, which means fewer people will open your emails and ISPs will continue to mark them as spam. It is a vicious circle - we know that.

By clearing your email list, you guarantee a better open rate, which is the number of emails that were opened out of the ones sent. This will not affect the total number of subscribers who read your emails. For example, if four out of a hundred people open messages, the number will remain the same, even if four out of fifty subscribers read them. The potential ROI for this campaign may not be the same but clearing your email list will affect your reputation among ISPs. And therein lies the key.

Nobody wants to have a bad sender reputation. The worse your reputation among ISPs, the more often your emails will end up in the spam folder. And as this happens, the number of subscribers who read your emails decreases, as do ROI and engagement.

There is another reason why you should check an email address and clean your list (if you are still not convinced). By dedicating your efforts to subscribers who are delighted with your brand, and not to those who never interact or may not even exist, you establish a better relationship with your active customers.

By focusing on them, you can create content tailored to their needs and interests, which will lead to better conversion levels and increase customer satisfaction. It is a win-win situation.

checking an email address

Signs that you need to check your mailing list

Although it is recommended to check your lists every six months, this can vary depending on the size and volume of the emails that you send. You may also find it necessary to further clear your list before or after a campaign is launched.

But, how to know if it is necessary? Here are some common symptoms of an email list that requires cleaning:

  • Rebounds are larger than normal or are growing at an unusual rate;
  • Opening rates are lower than normal or are falling at a higher rate than normal;
  • Spam complaints are higher than normal or are growing very fast.

By analyzing the delivery reports for each campaign sent, you know when the statistics are not ideal. If you have multiple lists, start with the one that has the worst deliverability results, as it probably has the most number of invalid contacts.

There are several reasons why you should check an email address and remove it from your mailing list. When you start to look deeper into the contacts on your list, you should be aware of the following types of "wrong" email addresses:

  • Duplicates: sending two or more identical emails to the same address repeatedly can be bothersome for anyone. Remove all duplicate email addresses from your list;
  • Aliases: Email aliases associated with a specific domain, such as or, are particularly problematic for providers, as not everyone has chosen to receive their emails;
  • Unknown: if there is someone on your list who has not explicitly agreed to receive promotional material from your company, including contacts purchased from third parties, the email address must be removed;
  • Bounces: there are two types of bounces; hard and soft. Hard bounces are permanent and include blocked and invalid email addresses. Soft bounces, on the other hand, are usually temporary and include automatic replies (which are normally used if someone is on vacation) and mailboxes too full to receive new messages.

Ways to check an email address

It doesn't matter how often you check your email addresses: the truth is that your mailing list grows over time. This is normal and expected, but how to check each and every email address, without it taking up precious time from your campaigns?

There are two main ways to do it: you can manually clear the list or use an email scanning service. What are the pros and cons of the options? Find out below.

check an email address

1. Clearing your list manually

Whenever you send your campaigns, you receive email messages that have returned, that is, that have not been delivered. One way to check an email address is to wait for returned accounts and remove them manually from your campaigns’ list.

The downside of this option is that too much time is wasted. In addition, you can only clear your list after sending your campaign, which means some of the damage has already been done (such as lowered sender reputation).

2. Checking an email address with Excel

Clearing your list manually is not a very practical option, which is why some digital marketers use Excel for this.

The program allows you to verify if the format of an email address is correct. The first thing is to check if it has an at sign (@) that is not in the first position and a period (.) after the at sign, which separates the domain from its position - for example,

To check if the "@" symbol exists, you must use the FIND function and do the same with the dot "."

Suppose in cell A1 we have an email, as

A1 =

The validation of "@" would be:

= FIND ("@"; A1)

This is another very laborious option, and not effective in determining all the problems that an email address can present.

3. Email validation in PHP

For those more familiar with programming languages, it is also possible to use PHP to check an email address.

In this case, you can not only check the syntax of the email, but also if it has special characters, which are not allowed in the composition of an account's address, or if it has more than the maximum character limit.

4. Email validation tools

It is evident that the options mentioned above are highly unattractive, or in some cases simply unfeasible. Whilst checking a mailing list manually can be excruciatingly time consuming and inefficient (depending on the size), checking in Excel or PHP may require considerable technical knowledge.

That is why the best choice for any email marketer is to use an email validation tool. The software does not send a message to its database to verify its authenticity - it uses different tests to validate email addresses, including syntax, domain validation, comparison with spam mails, SMTP connection, among others.

No matter the size of your mailing list, you simply need to upload a csv or an Excel file on to the system to validate the entries. That is it; the results will be delivered to you in a very short time.

In addition to identifying emails that have syntax errors, a validation tool also identifies role-based emails, inactive or deleted emails, spam traps, and accept-all emails.

TheChecker: the validation tool you need

TheChecker is an email list validation service to optimize the deliverability of your email campaigns. It provides an innovative solution that allows you to check and validate any type of subscription lists. It is also the only one on the market that guarantees a reliability of more than 99%.

Its mailing list cleaning function separates the email addresses according to the results. We offer you the option to check 100 addresses for free as a trial. Once you decide to purchase a credit package, there is no expiration date on it.

Try TheChecker now for free and start optimizing your campaigns' ROI by checking an email addresses. Let's kill the bounce!