Should You Remove Inactive Subscribers on Substack?

And How to Actually Do It Right

My Medium friends can read this story over there as well.

Photo by Sam Pak on Unsplash

You have thousands of subscribers, but are they really there?

Are they opening? Clicking? Breathing? (Kidding).

If not, should you cut them loose?

---

What Even Is Inactivity?

Before you delete half your email list, let’s define what “inactive” actually means.

Inactive subscribers — often called cold subscribers — are people who haven’t opened, clicked, or otherwise engaged with your content in a long time.

Pretty self-explanatory.

But that “long time” isn’t one-size-fits-all. It depends on how often you publish, in my experience.

Weekly publisher?

• If someone hasn’t opened anything in 6 months, they’re cold.

Monthly publisher?

• Give it more time — around 12 to 18 months. People might miss a few, but they’re not totally gone yet.

Daily publisher?

• That’s really hard to say. I’d still give it around 6 months of no opens before calling someone cold.

Of course, this is just a framework. You can tighten or loosen the timeline depending on how you feel.

---

Why You Should Remove Inactive Subscribers

Well, there are the obvious reasons:

Cleaner metrics

Bloated lists make your open rate look worse than it is. That skews your understanding of what’s working.

More accurate feedback

You’ll make better creative and strategic decisions when you’re only hearing from readers who are actually reading.

Better conversion potential

Dead subs don’t pay. Engaged ones might.

Simple decluttering

Yes, 10k looks nice. But if only 2k open your emails, does 10K really matter?

---

But here’s the big reason

Too many inactive subscribers can affect your deliverability. A lot!

If mailbox providers (Gmail, Outlook, etc.) see that your emails go consistently unopened, they start making assumptions — bad ones:

• That you’re irrelevant

• That you’re annoying

• That maybe you’re a bot, or worse… a marketer

You won’t get a warning. Your emails will just quietly slip into the Promotions tab, or worse, Spam.

At that point, it doesn’t matter how brilliant your subject lines are, no one will see them.

• Engaged subscribers? Gone.

• Potential conversions? Gone.

• Your newsletter’s reputation? Fading away.

This is the #1 reason to keep your list clean. Not ego. Not numbers. Not conversion rates.

It’s deliverability.

And once you're in spam, it’s a lot of work to get out. I know that from experience.

---

Why You Might Think Removing Inactive Subs Doesn’t Matter

Substack Doesn’t Charge You Per Subscriber

You’re not paying extra to keep cold subscribers.

That’s true.

Substack doesn’t pull a Mailchimp on you. Whether you have 5 or 50,000 free readers, it costs the same: $0.

So technically, you could keep inactive subs around.

I still think you shouldn’t. For the reasons I mentioned before:

• They hurt your open rate

• They damage your deliverability

• They distort your analytics

• They don’t help

---

Want to make your phone unique

Turn your iPhone home screen into a stunning Vision OS* version.

---

How to Clean Your List

The Problem With Just Looking at “Opens”

Let’s not oversimplify things. Just filtering by “opens = 0” is not enough. Substack’s tracking can miss real engagement because:

• App users don’t always trigger an “open”

• Apple Mail and other mail apps and services may hide open data

• Some readers browse on the web instead of clicking through the email

So yeah, someone might look inactive, but still read everything.

That’s why we need to layer filters.

Substack Filters

1. Filter by Activity = 0 Stars

No email opens, no web reads, no app activity in the last 30 days. This is your first clue.

2. Combine with “Emails Opened (Last 6 Months) = 0”

If they haven’t opened anything in half a year and they’re showing zero activity, you can be pretty confident they’re not coming back.

3. Add “Subscription Date = Before [e.g. Dec 1, 2024]”

Make sure you’re not punishing new people who haven’t had time to engage yet.

4. Filter for “Subscription Type = Free”

Let’s not accidentally delete paying readers. Even if they’re inactive, they’re paying.

---

What to Do With the Cold List

Now that you’ve got your likely inactives, don’t just rage-delete. Try this instead:

Step 1: Send a Re-Engagement Email

Keep it light, kind, and clear.

“Hey, haven’t seen you around lately. If you’d still like to get these emails, click here. If not, I’ll quietly remove you soon — no hard feelings.”

Make it easy for them to opt in or out.

Step 2: Give it a few days

Wait a week. You’ll be surprised who suddenly clicks when given the option.

Step 3: Reapply filters, then prune

If someone doesn’t respond or engage after the re-engagement email — they’re probably done.

Clean the list. You’ll feel better. Your stats will look better. And your emails will actually land in inboxes again.

---

The Bottom Line

Some people will tell you, you should never remove “inactive” subscribers. That’s because they have a different idea of what inactive means, and they know how you could screw this up.

Now you know how to find the “real inactives”.

TL;DR:

• Inactives = people who haven’t opened, clicked, or engaged in 6–18 months, depending on your publishing schedule.

• Too many inactives kill your deliverability. That’s the real danger. Spam filters don’t care how nice you are.

• Don’t rely on opens alone. Use filters: Activity stars, email history, subscription age, and type.

• Send a re-engagement email first, then prune.

• A clean list is a deliverable list. And a deliverable list is a powerful one.