Single Opt-In vs Double Opt-In – The Definitive Answer to the Age-Old Question

Have you ever wondered what opt-in process is the best for your email marketing campaigns? Is it single opt-in or double opt-in? Although the debate between these two processes has been going on for years, there wasn’t a definitive answer – until now.

Table Of Contents

What is single- and double opt-in? 

Single opt-in and double opt-in are the two most commonly used methods of obtaining consent from your subscribers. 

Single opt-in (or SOI) is a straightforward and simple process, consisting of only one step. A user subscribes to your email list by providing their email address through a signup form on your website, blog, or social media platform. Once the user submits their email address, they’re immediately added to your mailing list, ready to be used in your email marketing campaigns.

The double opt-in (or DOI) process, on the other hand, involves two steps. Just like in the single opt-in process, the user submits their email address through a signup form. However, before they’re added to your mailing list, they receive a confirmation email with a link or button they need to click to verify their subscription. 

Both methods have their pros and cons and you will find well-known marketing gurus on both sides of the debate, arguing tirelessly over which process is better. So, we have two hypotheses. 

Hypothesis A: Single opt-in is better

According to our Email Benchmarks Report, more than 90% of businesses use SOI in their subscription forms. This in itself should be a pretty solid argument for single opt-in. It’s impossible for this many people to be wrong about something, right? Right?

Theoretically, single opt-in has many benefits. Advocates for this process usually cite the following reasons.

Higher subscription rates

As I mentioned previously, the single opt-in process requires just one step from the user, making it more likely for them to complete the signup process. This results in a larger number of subscribers, allowing you to reach a wider audience.

User-friendly experience

The quick and straightforward process of SOI makes it more appealing to users. They don’t have to go through the extra step of confirming their email address, ensuring a seamless experience that can lead to increased trust and loyalty.

Faster list growth

As SOI helps to acquire more subscribers in a shorter amount of time, businesses can grow their email lists rapidly. This is particularly beneficial for new businesses or marketers looking to quickly expand their reach.

Less room for error

DOI confirmation emails may sometimes end up in spam folders or get overlooked by subscribers. With SOI, you eliminate this risk, ensuring that interested users are added to your list immediately.

Sounds convincing. But what about the double opt-in method?

Hypothesis B: Double opt-in is better

Did you ever provide a fake email address on a site just so you can download an interesting ebook or get access to some gated content? I know I have. The goal of using DOI is making sure your users are actually interested in receiving emails from you. 

People arguing for double opt-in usually list the following reasons.

Higher quality leads

By requiring users to confirm their subscription, DOI ensures that your subscribers are genuinely interested in your content. This can lead to higher engagement rates, better open rates, and increased conversions.

Reduced spam complaints

DOI helps to minimize the chances of people accidentally subscribing to your list or using fake email addresses. This can result in fewer spam complaints, which can improve your sender reputation.

Better email deliverability

As DOI ensures that your subscribers are real and interested, email service providers are more likely to view your emails as legitimate. This can improve your overall deliverability, allowing your emails to reach more inboxes.

Increased subscriber engagement

With DOI, subscribers have made a conscious decision to receive your emails, making them more likely to be engaged and responsive to your content. This can lead to a stronger relationship with your audience and better overall results for your email marketing campaigns.

We will revisit these claims for both methods later in the article.

The internet’s opinion on opt-in

When writing this article, I started my research the usual way – by searching for answers on Google. I tried many different queries – “double vs single opt-in”, “should I use double opt-in”, “double opt-in vs single opt-in” –, read dozens of articles, but didn’t find a conclusive answer to my question.

The general consensus seemed to be that SOI results in higher signup rates but lower engagement, while DOI is the opposite – lower signup rates but higher engagement. 

Intuitively, this does make sense. Double opt-in introduces friction into the subscription process, forcing users to jump through hoops. This additional confirmation step will result in many users never completing their subscription, resulting in lower conversion rates. However, those who do will be more engaged in the long-run.

That’s all well and good, but there is a lot of data missing. Does the drop-off in subscribers justify the increased engagement level? Most articles I read didn’t back up their claims by numbers, and those that did presented a wide range of differing figures. It didn’t help matters that most research was done on small samples, making their results less reliable and harder to generalize.

For a while, it seemed like I was stuck. That’s when I remembered The Great Detective’s immortal words.

It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.

Sherlock Holmes

If I wanted to find the answer, I had to do my own research.

Research methodology

GetResponse users send billions of emails every year. Some of these senders utilize single opt-in, while others employ double opt-in methods. If we compared the differences of their results, we would get the definitive answer to our question.

In order to ensure a fair comparison, we analyzed premium GetResponse SMB accounts from 2022, focusing on those using online subscription forms. We then examined the differences between SOI and DOI usage in terms of list size, subscription rate, unsubscribe rate, average newsletter open rate, average newsletter click-through rate, complaint rate, and bounce rate.

After examining a whopping 2.76 billion individual newsletters with the assistance of our Analytics team, I finally had the necessary data to reevaluate the assertions regarding SOI and DOI, and determine whether they held up under scrutiny.

Verifying the validity of claims on single- and double opt-in

People are more likely to subscribe to your email list with single opt-in – ✅ True

The data confirms that SOI often attracts more subscribers than DOI. In many industries, SOI subscription rates surpass those of DOI. The grand total reflects this trend, with SOI at 1.28%, which is significantly higher than the DOI rate of 0.33%. This suggests that single opt-in is generally more effective in attracting subscribers to your email list.

People subscribed with double opt-in are more likely to open your emails – ✅ True

A closer look at various industries reveals that DOI subscribers tend to open emails more frequently than SOI subscribers. For instance, the Arts & Entertainment sector sees a 41.95% open rate with DOI, while SOI lags at 19.71%. Overall, the grand total shows that double opt-in enjoys a 35.72% open rate, outperforming single opt-in at 27.36%.

People subscribed with double opt-in are more likely to click on links in your emails – ✅ True

Data clearly indicates that double opt-in subscribers are more inclined to click on links in your emails. The click-through rates for double opt-in are consistently higher across various industries.

People subscribed with double opt-in are less likely to unsubscribe – ❌ False

Contrary to popular belief, our data suggests that double opt-in subscribers are actually more likely to unsubscribe from your newsletters. For example, in Communications, the unsubscribe rate for DOI is 0.2397%, higher than the SOI rate of 0.0456%. The grand total also follows suit, with a 0.1084% unsubscribe rate for DOI and 0.0913% for SOI.

People subscribed with double opt-in are less likely to report your emails as spam – ❌ False

Our data doesn’t support the idea that DOI subscribers are less likely to mark emails as spam. On the contrary, in many cases, double opt-in spam complaint rates are higher than single opt-in.

This could be because double opt-in subscribers are more accustomed to engaging with your emails and taking action, while single opt-in users may be less engaged and more likely to ignore your emails, leading to them eventually landing in the junk folder.

Using double opt-in will reduce your bounce rate –❔Inconclusive

The impact of DOI on bounce rates is inconclusive, as it varies across industries. In Arts & Entertainment, DOI enjoys a lower bounce rate of 1.72% compared to SOI’s 4.26%. However, in Automotive, DOI bounce rate is higher at 3.78% against SOI’s 1.16%. 

The grand total presents a mixed picture, with the DOI bounce rate at 2.38% and SOI rate at 2.14%. These results suggest that the impact of double opt-in on bounce rates varies by industry and is not universally conclusive.

The final answer

Now that we know that double opt-in won’t necessarily lower your unsubscribe and complaint rates, it all comes down to this – is the increased subscriber engagement worth the lower subscription rates?

We are all after the “clickers” – subscribers who open your emails and click on your links. These are the people that you can convert into paying customers. In order for a person to become a clicker, they need to:

• Visit your website or subscription form
• Successfully subscribe to your email list
• Open your newsletter
• Click on the CTA in the email

We know from our research that the average subscription rate of a single opt-in form is 1.28% and the subscription rate of a double opt-in form is 0.33%. We also know that the average CTR of a newsletter is 2.36% for a SOI audience and 4.19% for a DOI audience. We can organize our data like this:

	Single opt-in	Double opt-in
Visitor to subscriber conversion rate	1.28%	0.33%
Newsletter open rate	27.36%	35.72%
Newsletter click-through rate	2.36%	4.19%

By multiplying the number of visitors with the visitor-to-subscriber conversion rate and the average click-through rate of a newsletter campaign, we get our answer. To make it easier to understand, let’s assume that you are just starting your online business and you are expecting around 1 million unique website visitors in your first year. 

Should you use SOI or DOI? Let’s take a look at the numbers!

	Single opt-in	Double opt-in
Number of visitors	1,000,0000	1,000,0000
Number of subscribers	12,800	3,300
Average number of people opening a newsletter	3,502	1,178
Average number of people clicking on a link in a newsletter	302	138

So, there you have it. Single opt-in outperforms double opt-in in every possible regard. According to our research, SOI will grow your email list faster, get more impressions on your emails and you can convert more subscribers into paying customers.

Case closed? Well, it depends. In the words of a famous sports commentator:

Statistics are like a drunk with a lamppost: used more for support than illumination.

Vin Scully

Different businesses have different target audiences, email marketing strategies, and conversion goals. It’s important to test and analyze the effectiveness of both single opt-in and double opt-in for your specific business and audience. 

Ultimately, the decision should be based on what works best for your unique situation, rather than relying solely on statistical averages.

Alternatives to double opt-in

If you want the best of both worlds, use single opt-in but consider using the following tactics.

Send your lead magnets in email

Instead of simply gating your lead magnet content behind a signup form, consider sending it over in email instead to subscribers. This will discourage people from providing fake email addresses and ensure that your subscribers engage with your content.

Send welcome emails with a strong CTA

Use your welcome email to encourage users to take action, such as visiting your website, downloading an app, or following you on social media. This can help build a relationship with your subscribers from the start.

Use an email verification service

One of the key pillars of a healthy email list is making sure that the emails on your lists are valid. GetResponse automatically removes invalid emails, but if you want to be on the safe side, consider using an email validation tool.

Use engagement scoring

Monitoring the engagement levels of your subscribers is crucial, as a low average engagement rate can hurt your email deliverability. GetResponse automatically scores your subscribers’ engagement on a 1 to 5 scale, where 5 marks your most engaged subscribers. You can use this data to segment your audience and better tailor your messages to them.

Regularly clean your email lists

Sometimes, it’s better to let go. If someone is never engaging with emails, you might be better off removing them from your list. Fortunately, you don’t have to do this manually – just use a GetResponse workflow for automatically removing your disengaged subscribers.

Use consent fields

Use checkboxes or other forms of consent to ensure that subscribers are fully aware of what they are signing up for and have given explicit permission for you to send them emails. This can help ensure that your subscribers are engaged and interested in your content.

Wrapping it up

The single opt-in vs double opt-in debate has finally reached its conclusion – at least, according to our research. Single opt-in seems to be the clear winner in terms of growing your email list, garnering more impressions, and converting subscribers into customers. However, it’s crucial to remember that every business is unique, and what works for one may not work for another.

While our research presents a strong case for the single opt-in method, we encourage you to test and analyze the effectiveness of both methods for your specific business and audience.