The Only Subject Line Formula You’ll Ever Need

Instantly create irresistible subject lines that grab attention.

This one subject line formula gets me 35% – 57% open rates.

Here’s the formula…

It’s called the “CBP Formula” for email subject lines.

CBP stands for Curiosity + Benefit + Proof.

Let’s break it down.

1.) Curiosity

Say something that sparks the reader’s curiosity.


– My mom threw wine on me & I deserved it
– Add this to your calendar
– Will {first_name} be there?

These are 100% curiosity-based and don’t promise a benefit to the reader.

2.) Benefit

What’s in it for the reader?

How will the reader’s life be better by clicking the email?


– Never feel lost stuck or confused ever again!
– Add $20k – $30k to your MRR in 30 days
– Melt away stubborn belly fat in your sleep

As you can see, benefits can be either direct or indirect.

3.) Proof

Add elements of credibility to make the subject line more believable.


– 62-year-old former marine saves 3 lives during a liquor store robbery
– Netflix & Tesla’s $2.73 trillion dollar merger
– Harvard Medical grad makes $2,112 a week on autopilot w/ Thrive Cart

Here are a few things you can add to a subject line to boost proof…

- Specific numbers: 522.34 is more believable than 500+ or 500
– Trusted or hated celebrities/ politicians/ companies
– Smart people: doctors, lawyers, scientists, etc. (Use their names IF you can)

One last example.

Let’s put together everything you’ve learned.

“62 yr old ex-marine makes $511/week from Netflix price hike”

Here’s the breakdown…

– Curiosity: How can anyone make $511 a week from Netflix’s price hike?
– Benefit: Make $511 per week ($2,044 per/mo)
– Proof: $511, Netflix’s recent price hike, 62-year-old marine.

So to recap…

The CBP formula is great for crafting powerful email subject lines.

Which can dramatically increase your email open rates.

CBP = Curiosity + Benefit + Proof

C: Spark your reader’s curiosity.

B: What’s in it for me? (WIIFM)

P: Add credibility.

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Derek Coleman B2B newsletter copywriter for SaaS companies

About the author

Derek Coleman is an AWAI-verified direct response B2B copywriter, email marketer, and author of 3 books.

He specializes in helping B2B SaaS companies get more leads, sales, and conversions from their email list. Derek has served 160+ happy clients as a freelance copywriter for hire!