After testing many products, I have found Formidable all that I need!
Last updated on May 23, 2025 by Formidable Team
Single Opt-in vs. Double Opt-in: What's the Difference?
Single opt-in vs. double opt-in — what’s the real difference? Find out how each impacts your email list and user engagement in this helpful guide.
Approximate read time: 6 minutes
Building an email list?
One of the first decisions you'll face is choosing between single opt-in and double opt-in. This choice affects not only how quickly your list grows but also the quality of your subscribers. Single-opt-in makes signing up easy, while double-opt-in adds an extra step for confirmation.
Both have pros and cons. And picking the right one depends on your goals.
In this post, we'll explain the differences and help you determine which method best suits your email strategy.
Let's dive in.
Upgrade your WordPress site with powerful, flexible forms.
What is single opt-in?
Single opt-in is a simple method for creating an email list.
When you add an email subscription form, and someone fills it out, they're immediately added to an email list. That's it. One step, and they're in.
This makes it great for businesses looking to grow their list quickly, but there are trade-offs (we'll get to those soon).
Advantages
- Faster list growth: Since there's no confirmation step, more people end up on your list. If you're launching a new product or running a promotion, a single opt-in helps reach a larger audience.
- Less friction: The single opt-in process is easier for subscribers. All they do is enter their email, and they're signed up. You avoid losing them if they forget to confirm or it ends up in their spam box.
Disadvantages
- Lower engagement: While single opt-in grows your list faster, it often leads to lower engagement. People who don't confirm their email may be less interested in your content, so they may ignore your emails.
- Risk of invalid or spam emails: Because subscribers don't confirm their email, you risk fake or mistyped emails slipping into your list. This means higher bounce rates and affects your sender's reputation.
- Deliverability issues: Those fake or spam emails also mean your messages could be marked as spam. And this hurts your overall deliverability — making it harder to reach real subscribers.
From Idea to Reality in Minutes. Build Powerful Forms, Dashboards, Apps and More.
Formidable Forms makes advanced site building simple. Launch forms, directories, dashboards, and custom WordPress apps faster than ever before.
What is double opt-in?
Double opt-in is a two-step process for subscribing to an email list.
After someone enters their email in a sign-up form, they get a double opt-in confirmation email. To complete the signup, they must open the email and confirm their subscription by going to a confirmation page or landing page.
This extra step ensures that only valid (and interested) subscribers make it on your list.
Advantages
- Higher-quality subscribers: Because you can verify email addresses, you know they're interested in your messages, which means a more engaged list.
- Better deliverability: Double opt-in lowers the chances of fake or invalid email addresses. Fewer bounce-backs and spam reports improve your sender reputation and increase your emails' chances in inboxes.
- Improved engagement: Double opt-in lists have higher open and click-through rates than single opt-in lists. And because subscribers are more invested, you get better engagement — quality over quantity.
Disadvantages
- Slower list growth: Double opt-in leads to fewer overall subscribers because some people don't confirm their email.
- More friction for subscribers: The extra confirmation adds a bit of friction. And any amount can lead to a dropoff of subscribers with each step.
- Delayed access: Double opt-in delays subscribers' ability to receive emails immediately for more time-sensitive promotions. For example, take WordPress. Sometimes WordPress doesn't send emails at all.
Comparing single opt-in vs. double opt-in
Now that we know how single and double opt-in work, let's compare them directly.
Each method has pros and cons; understanding these will help you determine the best situation.
List growth
Single opt-in: This method is great for fast list growth. Since subscribers don't have to confirm their email, more people are added immediately, making you less likely to lose subscribers to missed or ignored confirmation emails.
Double opt-in: One of the biggest downsides of double opt-in is a lower number of subscribers. Some users might not complete the confirmation step, which means a higher drop-off in subscribers. So, your list will grow much slower.
Subscriber quality
Single opt-in: While it is faster, single opt-in often means lower-quality subscribers. Some people may fill out a signup form and never engage with your emails, which hurts open rates. You might also collect fake email addresses, which hurts.
Double opt-in: With double opt-in, subscribers take steps to ensure they're on your list. That means more engaged subscribers who turn into long-term subscribers, which leads to better conversion rates. Many email marketing plugins will have a way to track this.
Engagement and deliverability
Single opt-in: As we touched on earlier, lists with single opt-in tend to have lower open and click rates. Some subscribers may forget they signed up, mistyped, or have your email campaigns sent to their spam folder. All of this hurts your sender's reputation.
Double opt-in: Double opt-in generally has higher open and click rates because subscribers show interest through confirmation. There are no fake or invalid emails, and there are no spam boxes. This leads to overall better email deliverability.
User experience
Single opt-in: Single opt-in is quick and easy for users. There's no extra step, which means less friction for subscribers. This can be especially useful in industries where speed and simplicity are key to conversions.
Double opt-in: The extra step of confirming may frustrate some users. And it's possible the confirmation email gets lost in their inbox. So, some friction may lead some users to drop off. But that's your risk if you want a more engaged audience.
Which one is right for you?
This comes down to everyone's favorite answer: it depends on your goals.
- Choose single opt-in if: You want fast list growth and are willing to accept that you'll get some lower-quality subscribers. This is especially great for time-sensitive promotions or businesses just starting and looking to grow an email list.
- Choose double opt-in if: you want quality over quantity. This is the route to go if you want subscribers genuinely interested in the service/product offered.
It also depends on your email marketing strategy and service. Tools like Mailchimp, Constant Contact, ActiveCampaign, and more all have ways of handling this.
What will you choose in the double opt-in vs. single opt-in debate?
Whether you choose single or double email opt-in, it's great to test both, depending on your situation. But, no matter which one you choose, it's also great to have a way to build forms that help convert. And if you're using WordPress, the best way to do that is using the best WordPress form builder: Formidable Forms.
It integrates with Mailchimp, MailPoet, Constant Contact, and more email services, giving you more power to customize your forms.
Also, join our community on Facebook, Twitter, LinkedIn and YouTube for more WordPress and email tips and tricks!
Read more about email marketing!
How To Add a ConvertKit Form to WordPress [Only 5 Steps!]
9 Great Abandoned Cart Email Examples & How To Make Your Own
MailPoet vs. Mailchimp [Which is Better for You?]This article may contain affiliate links. Once in a while, we earn commissions from those links. But we only recommend products we like, with or without commissions.
